Code P0335 - Engine blown

04crewvt · Post by **04crewvt** » Mon Jul 14, 2008 3:39 pm

Severe drive ability problem today. After filling up this A.M. and getting on the highway I noticed a surge in the tach when down shifting on the hills, it would move the needle rapidly from 2000-4000rpm at slow speed no problem seen. On the way home tonight code P0335 set engine lost power and tach was all over the place. From what I could find this looks like the crank position sensor acting up. Would there be any reason for this to occur soon after having the intake gaskets done? I did see a 1MPG loss in mileage with this tank which was the 2nd since the gaskets were replaced a week ago and this weekend I did remove the turbinator(tornado thingy) from the air intake to see if it was effecting my gas mileage.

Post by **HenryJ** » Mon Jul 14, 2008 3:50 pm

Check the cap, rotor, cam position sensor and distributor housing. Easy to do and will eliminate some possibilities.

04crewvt · Post by **04crewvt** » Tue Jul 15, 2008 6:07 pm

Cap and rotor seemed ok I drove (limped it more like) it in to the shop this A.M. They got the same codes so they tried a crankshaft relearn procedure and thought it was all set. I went to pick it up and it was still having problems. They had said if the code came back they would need to replace the sensor. As this was near the end of the day I was hoping it could be done in time for me to drive it home. They got a new sensor, installed it and found out it was bad out of the box, by the time they could get a new one I had to leave it overnight. Good thing a buddy of mine at work lives 20 minutes away. Only thing I had to endure was some time at the local arcade/pizza place with him and his son and his sons mother and a few dozen screaming children. It was that or a hotel room for the night. Hopefully the sensor will fix the problem and they would find anything else wrong. I did remember to remove the HPPIII tuning before I brought it in.

04crewvt · Post by **04crewvt** » Fri Jul 18, 2008 8:07 am

Update-- My truck is still in the shop. The crankshaft position sensor has been replaced by a GM unit but they couldn't get their SnapOn scanner to calibrate it. They have checked the fuel pump, tested the distributor , all the plugs and wires are new, and finally gave up and have sent it to the dealership where they have been working on it for the last 3 hours. The truck will idle normally but as soon as you step on the gas it starts to misfire. Currently they are in the process of guessing and replacing parts to see what's up. PCM failure is certainly a possibility at this point but they checked all the voltages and it seems fine.

Post by **HenryJ** » Fri Jul 18, 2008 8:38 am

A worn drive gear for the distributor comes to mind, as does the spider assembly.

04crewvt · Post by **04crewvt** » Fri Jul 18, 2008 9:13 am

That's a possibility, I just called them to have them check the pre-cat and cat for problems as well since I did just have a coolant leak fixed and we have a threads about how a plugged precat/cat can cause idling and drive ability problems I figured why not, if it turns out to be that it all should be covered under the emissions warranty. The guy I spoke to at the dealer (not the one doing the work) didn't even know there was a pre cat on this truck he had never heard of it.

Post by **HenryJ** » Fri Jul 18, 2008 10:04 am

I was going on the scanner problem. The inability to properly phase the crank sensor could be related to a cam sensor beyond the calibration parameters? That was my train of thought for a worn dist drive gear.

Educate them. We here have spent way more time trying to figure these trucks out than any tech would ever dream.

04crewvt · Post by **04crewvt** » Mon Jul 21, 2008 7:45 am

I just called the shop, It seems the air gap on the crankshaft position sensor was off and required a shim installed. If I recall there was a TSB on this issue and I let the shop know this, they are checking with the dealership . I can't seem to find any info on this on the site but I am at work right now without time to research it. If anyone has the TSB # handy or can find it I would appreciate it.

Just got word the truck is back from the dealership, they wouldn't cover it since it's not a recall but they did knock some off the bill. Worst thing is they spent quite a bit of time checking things before calling it in for tech support which told them the answer right off the bat, had they called first it might have saved me some $$$ as it is the total tab ended up at $649.45 $147 to the shop that installed the sensor and $478.80 for diagnostic time and repair at the dealership. I just hope my MPG goes up so it's worth the cost.

Between this and the intake gasket failure I am debating writing to GM and the local shop to see if they can help me out. Seems wrong that a truck with 57K on it has so many problems at one time.

I will wait to mark this one SOLVED till I get it back and see how it runs.

04crewvt · Post by **04crewvt** » Mon Jul 21, 2008 1:51 pm

Seems to be running fine, I will see on the way home how it acts but for now I think it's fixed.

F9K9 · Post by **F9K9** » Mon Jul 21, 2008 1:54 pm

Glad you "might" have it fixed, Brian.

04crewvt · Post by **04crewvt** » Tue Jul 22, 2008 6:02 am

Well the P0335 code is gone, unfortunately I am now getting a P0300(multiple cylinder misfire) on heavy acceleration on hills. The plugs were changed to Autolite iridiums with new plug wires just 2k or so ago. distributor cap and rotor were replaced about this time last year. Looks like I have some more head scratching to do to get this running right. Will start with checking for loose battery connections, condition of cap and rotor, plug wires seated properly and not arcing, then have to move on to coil, ignition module and who knows what else. I will pick up a can of injector cleaner to see if that helps but I have been doing that every 3k or so. Any other ideas for me to check?

barch97 · Post by **barch97** » Tue Jul 22, 2008 9:10 am

Check that cap. I had kinda similar symptoms and found the #3 contact to be burnt shortly after replacing cap.

04crewvt · Post by **04crewvt** » Tue Jul 22, 2008 9:57 am

I spoke with the place I have been having work done, they supposedly checked the cap, rotor and had even put a different distributor in when working on the other problems. They are as puzzled as I am. I have it scheduled to go back in tomorrow morning.. I am going to try to hook my AutoXray scan tool up and do a live capture of data tonight on the ride home to see if I can narrow down the problem.

Post by **HenryJ** » Tue Jul 22, 2008 2:44 pm

This whole thing is eerily similar to Justin's plight from about five years ago. He fought it for over a year IIRC.
They did the same crank sensor replacement. It went back in for shims. Then he had random misfires, so they blamed the injectors. They cleaned them. Still there so they updated the injectors to MFI. Still problems so they replaced the engine. Pretty sure he sold it not long after that.
service engine light
follow up on my service engine problem
SES code 300
I'm getting a brand new motor for free!

Justin wrote:C/S service engine soon light is on solid. checked for dtc's found P0300. Checked misfire data found multiple cylinder missfires. Removed distributor cap and found moisture in the cap and little corrosion on the rotor. replaced cap and rotor and #4 keeps misfireing. swapped the wire and plug and it did not change the location of the missfire. Called technical assistance and had me add shims to the crank sensor, check the exhaust for back pressure, check the fuel pressure. check the tdc at 0 relearn the crank veriation after each shim installed. replaced the cranks sensor. check the mass air flow sensor. replaced the #4 injector with the newer version injector system. Pull the front cover off and inspect the dol pins for being broken. If this is not broken then to replace the motor. Asper steve young, head of 4300 engine program. replaced the engine and all needed gaskets. changed the oil and the antifreeze as needed. Road tested to verify the repair.

so here is what i got

motor

gaskets

oil + filter

antifreeze

cap

rotor

crank sensor

new fuel injector

fuel filter

full tank of gas

and a rental for 2 weeks

04crewvt · Post by **04crewvt** » Tue Jul 22, 2008 4:15 pm

Yea - I was reading that combination of threads. The codes did not come on tonight. I even had my AutoXray scanner hooked up to capture data when it did so I would have a better idea what is going on. What I will say is this most often happens when the temp is more than 60 outside and very humid. I wonder if the ignition module or coil are being effected buy the damp, might be time for some hairspray. I doubt I will so lucky as to get a new motor

04crewvt · Post by **04crewvt** » Wed Jul 23, 2008 11:53 am

I took the truck back to the shop today and let them us it for their daily running around to see what they could find. It would not set a code last night or this AM but they could feel the same thing I can, it's a loss of power and a roughness that wasn't there before. They check everything they could including back pressure in case the cat or pre-cat were bad -nothing. They recommend I take it back to the dealership that just spent 7 hours on it to see if they can figure it out. I wonder if this truck doesn't like the iridium plugs?

Post by **HenryJ** » Wed Jul 23, 2008 2:37 pm

Do you still have the stock plugs? You might try swapping if you do.
I like the Autolite iridium plugs, but I am also running a Blaster coil and MSD.

Your problem may require some detective work on your part. There is nothing worse than trying to find something when the operator says it is not the same and runs funny.

Answer all the usual questions. When did this start. What was done that may have cased it at that time. What provokes it. What have you been feeding it.

Double check and triple check. Don't assume new parts are good. I have heard of cases where the replacement distributors were clocked incorrectly and it was not possible to correctly align them. Things can change quickly. The last time checked may have been when the ear on the distributor cracked.

Fuel pressure checks and looking for vacuum leaks are always good ideas. Check the hoses behind the brake booster.

04crewvt · Post by **04crewvt** » Thu Jul 24, 2008 5:24 am

Code P0420 set this AM O2 sensor bank 1 this is the bank I originally got a P0303 code I wonder now if the coolant leak fouled the O2 sensors?

04crewvt · Post by **04crewvt** » Thu Aug 14, 2008 5:45 am

UPDATE-
My truck is still not right, P0300 code comes back constantly. Dealership can't find the problem until all stock parts are reinstalled according to them so back to the first shop. 1st put factory plugs in 90 miles and code sets again, then factory cap and rotor same thing, today it's in for factory plug wires. This will make the engine completely stock except for the descreened MAF and high flow air filter. When the code sets again the dealership should look at it. The only constant is the light comes on at about 90 miles after working on the truck and it's under load keeping up at highway speed going up hill. You occasionally can feel a stumble at low speed when accelerating from a stop.

roadrunner · Post by **roadrunner** » Thu Aug 14, 2008 5:51 pm

Maybe a stretch but check your O2 sensor wiring and connectors. I had a similiar situation to what you are describing a year or so ago and my truck also kept setting the P0300 multiple misfire code. My bank 2 sensor 1 wiring had some problems. One shorting wire and a bad connection in the harness connector. Never did set a code for the sensor though. Repaired the wires and connector and the multiple misfire and it's code went away and have not returned since.

BTW the rear sensor was at nearly the same stage of wire problems so I repaired it at the same time to save trouble later. Bank 1 Sensor 1 was okay upon close inspection.

04crewvt · Post by **04crewvt** » Thu Aug 14, 2008 6:04 pm

Scangauge is showing good voltages from all sensors. I now am crossing my fingers that the wires did the trick, my guess is that the code will come back by tomorrow night if timing is consistent with the mileage between setting the code. At that point it's back to the dealership for more time under the scanner. They wouldn't go any further until the vehicle was back to stock. Everything from cat,O2 sensors, distributor,coil, injection system, IAC, ignition module and PCM have been mentioned as possible culprits. I feel like I am swinging blind at a parts pinata with a stick made of Ben Franklins.

brandons4door · Post by **brandons4door** » Thu Aug 14, 2008 8:05 pm

I don't have the slightest mechanical advice for ya, but I'll happily say a prayer. Good luck.

04crewvt · Post by **04crewvt** » Sat Aug 16, 2008 2:19 pm

As expected, code came back in less than 60 miles. I am scheduled into the dealers again on Monday. I now have a complete set of plug wires and AutoLite double platinum plugs with less than 3k on them sitting in boxes and will have a new cap and rotor as well, once I get to the parts place and get a warrantied replacement set.

Post by **HenryJ** » Sat Aug 16, 2008 2:32 pm

I'd say you're about...

-> service engine light
-> follow up on my service engine problem
HERE -> SES code 300
I'm getting a brand new motor for free!

04crewvt · Post by **04crewvt** » Sat Aug 16, 2008 2:40 pm

Sounds about right but my guess is the new motor part will be a hard sell since it is out of warranty. I just wish the random occasional check engine lights that had been coming since I got the truck had set the code a little sooner.

04crewvt · Post by **04crewvt** » Wed Aug 20, 2008 3:14 am

Closer and closer to a new motor--- After another $600 to replace a faulty fuel pressure regulator they were able to get the misfire down to 1 cylinder or so they said. Unfortunately they also found a great deal of metal shaving stuck to the oil drain plug magnet. They are now of the opinion I have at least one or more bearings bad and the engine is running worse than ever after picking it up yesterday. The RPM's go haywire and the engine started clacking away like mad 5 minutes after leaving the dealer's lot. I will be limping it in and dropping it off again this morning. My bet is a new motor is going to be the only fix for this.

F9K9 · Post by **F9K9** » Wed Aug 20, 2008 4:44 am

I smell baked duck

04crewvt · Post by **04crewvt** » Wed Aug 20, 2008 5:25 am

Fried more like-- I managed to get it to the dealers but it was making lots of noise, 1 mile from their lot I got a large puff of smoke out the tailpipe and my oil pressure dropped to 0. I expect the worst.

04crewvt · Post by **04crewvt** » Wed Aug 20, 2008 10:23 am

Well as I suspected - The motor apparently shredded a bearing it's toast. Replacement has been quoted at $5300.00 and at least 10 days before I see it. Figuring out what to do now.

F9K9 · Post by **F9K9** » Wed Aug 20, 2008 3:15 pm

I'd look at Jasper remans and have a small shop do it. For 5300 you can get a crate motor for around 3k and have a serious V-8. I'm sorry Brian. You have had more than your fair share waterfowl!

Post by **HenryJ** » Wed Aug 20, 2008 3:17 pm

What oil were you using, and what service interval?

You can buy a long block for under $2000. I have not checked my price through GM for a crate engine, but I would bet it will be comparable, as the last V-8 I bought was $2000.
Add to that $1000 for parts and incidentals. The rest should be labor.
You should end up with at least a 3 year 100k mile warranty on the engine. GMs warranty is unlimited mileage now.

The swap is not too hard. Cleaning all the parts is what takes most of the time. Figure three weekends if you are doing it in your spare time. That will include some parts running during the week and in between.

If this truck is not your love and you don't plan on driving it another 100k miles, consider having a used engine installed. You could probably have that done for 1/3 the cost. Plan on that being a 3 year fix.

Lots to think about.

Wanna throw a monkey wrench in the mix? Have you had your V-8 today?

F9K9 · Post by **F9K9** » Wed Aug 20, 2008 3:23 pm

HenryJ wrote:What oil were you using, and what service interval?

Ouch!

Post by **HenryJ** » Wed Aug 20, 2008 3:28 pm

f9k9 wrote:
HenryJ wrote:What oil were you using, and what service interval?
Ouch!

Sorry! I am genuinely curious.

F9K9 · Post by **F9K9** » Wed Aug 20, 2008 3:30 pm

Amsoil and way to long of intervals IIRC.

Post by **HenryJ** » Wed Aug 20, 2008 3:32 pm

f9k9 wrote:Amsoil and way to long of intervals IIRC.

04crewvt wrote:I am running the Amsoil synthetic and have changed the oil exactly 3 times since I got the truck at 6700K.

Ahh, you are right! Sorry, I am rather slow. I did not even relate the maintenance schedule with this problem until now. So much for the superior protection and longer service intervals. Looks like more frequent changes might have been cheaper in the long run?

How many miles on it now?

Guess the knock sensors sensing the knock was the problem all along. No way to back the timing off far enough to keep the bearings from beating themselves.

04crewvt · Post by **04crewvt** » Wed Aug 20, 2008 4:13 pm

Actually while the long interval "might" have been part of the problem I think the intake leak of Dex is more likely the problem. I had checked the oil frequently and never saw a problem but I did occasionally got a whiff of antifreeze when the engine was hot. I never had to top off the overflow and it never showed hot on the gauge but my guess is it had been a problem for a long while. I had the SES light come on once every 6 months or since I got it with 6700 miles on it or so but never would set a code to look at. Now that I think back I had heard a little engine noise last winter on the really cold days my guess is that's when the problem really started to get serious. The first long trip I had done in two years was just about the time I found out the coolant was leaking I guess that was one trip to many. I currently have 58k on the truck.

Post by **HenryJ** » Wed Aug 20, 2008 4:30 pm

I would suggest going "green" coolant with what ever engine you decide to install.
Shorter duration service intervals give you a chance to inspect the oil for contaminants, at the very least. If you insist on running the Ams. on long intervals, invest in a filter cutter and spend some time inspecting the filter and small sample of oil it contains. Those may give you some evidence for impending doom.

I am sorry, but for me this is related to the Amsoil failing and their recommendations for the maintenance schedule. I see this as one more case to learn from.
Don't you have recourse through Amsoil? I thought they guaranteed replacement if it was a failure of their product to perform as advertised? Don't they pay for the replacement engine if you followed their recommendations?

I say this since I have fixed many Dex leaking intakes and even the worst did not destroy the engine. It is possible, and obviously more likely if you never change the oil to remove the contamination, but still. Dex was designed to be easier on bearings.

04crewvt · Post by **04crewvt** » Wed Aug 20, 2008 5:13 pm

My guess is each will say the other was at fault. But I will see what happens. I will be filing a claim with GM to see if they will cover any part of the repair. My guess is there will be no proof either way of what caused the failure. Since I am unlikely to see what really happened I have no way to say if anyone was at fault. I will definitely check things more frequently from now on guess I got lazy after loosing my shop to work in. At a minimum I will check the oil and filter regularly. I had planned on getting the oil bypass filter system and sending in oil samples but just had not gotten to it. Live and learn I guess, just glad I am not making payment as well.

F9K9 · Post by **F9K9** » Wed Aug 20, 2008 7:31 pm

04crewvt wrote:.............. glad I am not making payment as well.

AMEN!

green02crew · Post by **green02crew** » Thu Aug 21, 2008 4:36 am

That is pretty tough. Atleast it wasn't a huge surprise and you expected to have issues not some day on your way to work. At the quoted cost of replacement I would go V8 no question. Especially with the year of your vehicle and fuel prices it would get much higher economy as well. I have weekends if you ever need a hand, not that my hands are amazingly skilled at anything.

roadrunner · Post by **roadrunner** » Thu Aug 21, 2008 2:03 pm

Sorry to hear about the truck Brian. Kinda holds with my previous experiences with synthetics in general. I'll stay happy (and so will my truck) with my dino oil and frequent changes.

04crewvt · Post by **04crewvt** » Thu Aug 21, 2008 3:19 pm

Any feelings for or against a Jasper replacement motor? The local Chevy place priced one out to me for $1250 less than the GM crate motor with the return to Jasper of my old block.

Post by **HenryJ** » Thu Aug 21, 2008 3:21 pm

I hear good things. What is their warranty?

04crewvt · Post by **04crewvt** » Thu Aug 21, 2008 3:23 pm

3year/100k just the same as the GM crate motor when installed in a shop and not used for commercial vehicle.

Post by **HenryJ** » Thu Aug 21, 2008 4:17 pm

Sounds like a winner to me. I have no first hand experience with them , as they seem to be more of a right coast thing.
As long as that is a long block quote, it sounds pretty good.

04crewvt · Post by **04crewvt** » Thu Aug 21, 2008 4:37 pm

Yes this is a complete re manufactured long block and cost is $3721 out the door. Warranty is also covered for Labor. Only thing they might need to add are any hoses /belts that look bad and they might have to replace the external oil cooler to be covered under warranty.

F9K9 · Post by **F9K9** » Thu Aug 21, 2008 4:38 pm

Brian, I am still leaning towards a small shop with credentials and references versus a dealership. Heck my heep has 83K on it and I am already looking at custom stroked engines that increase them from 4.0 to 4.6L for whenever the time comes.

04crewvt · Post by **04crewvt** » Thu Aug 21, 2008 4:45 pm

Yea but the parental units are floating the bill for me right now. Things are a little tight right now at work (lost all my OT) so they have a say in what happens. If I had the cash it might be a good time to go V8 but for now it's the next best to stock with an upgraded block and components. If I wanted to keep the block and do a custom build like I did on my old 2.8l I could have a killer 4.3l but my buddy wants his garage space back, not have me put more in there.

F9K9 · Post by **F9K9** » Thu Aug 21, 2008 5:53 pm

f9k9 wrote:Brian, I am still leaning towards a small shop with credentials and references versus a dealership.......

Understood but, I still stand with this option for the Jasper reman.

04crewvt · Post by **04crewvt** » Thu Aug 21, 2008 6:05 pm

Trying to find a quality aftermarket shop that doesn't charge just as much as the dealerships has eluded me since I came up here. I have had a few shops that I trusted with most things but not big things. I have worked with this dealership many times and trust what they do as much as I trust anyone. With the Jasper reman they do require a certified installer to make good on the warranty There are only 2 listed on their web site for my area and I have never used them, as it is I have to make sure the dealership can do this for me since they are not listed. I have heard good things about one of the other shops so I will check their price tomorrow and see what they can do for me.

04crewvt · Post by **04crewvt** » Fri Aug 22, 2008 11:38 am

Local 4x4 shop that is Jasper preferred dealer quoted me $900 more than the dealership so the crew is on it's way from the Pontiac shop, down the road to the Chevy shop. AAA comes in handy again, I called from work and it's magically whisked away. The Jasper motor is ordered and they expect to have the truck back up and running late next week if all goes well.
- KEEP ALL DUCKS FAR AWAY -

green02crew · Post by **green02crew** » Fri Aug 22, 2008 1:01 pm

Is it another 4.3?

04crewvt · Post by **04crewvt** » Fri Aug 22, 2008 1:14 pm

Yup - Not going to get into modding when it's likely I will at least try to see if GM will help out with the bills.

04crewvt · Post by **04crewvt** » Fri Aug 29, 2008 4:35 pm

New engine is in and paid for I just have to go pick it up. I will let everyone know how it runs when I get it and put some miles on it.

04crewvt · Post by **04crewvt** » Sat Aug 30, 2008 2:05 pm

Well for the first time in nearly two months I made it home without the check engine light coming on. Here is hoping for the best. Only beef I have with them is the put in a new set of plugs at the tune of $73 when the A/C Delco's in there had only been in there 100 miles I will be speaking with them about that Tuesday as well when I complain about the tail gate cables from the other thread.

F9K9 · Post by **F9K9** » Sat Aug 30, 2008 2:39 pm

Brian, I know you are probably in a "break in" period with that reman motor but, any 1st impressions? Glad you are rolling again

04crewvt · Post by **04crewvt** » Sat Aug 30, 2008 2:58 pm

1st impressions are favorable good power, RPM's where they were on the old motor. Good passing speed ran a mix of stop and go as well as 70mph highway and 35-40 mph back roads for about 35 miles no issues. I just hope the gas mileage is as good or better than before and of course that was without the HPPIII tuning yet.

F9K9 · Post by **F9K9** » Sat Aug 30, 2008 3:06 pm

Once break in procedures are over I would like to recommend using synthetics per reman's instructions. Don't overlook Wallyworld's synthetic lubricants. Allot of their stuff surpasses Mobil1 and other well advertised brands, including Royal Purple. Don't want to start anything here but, I can PM you some excellent info later.

04crewvt · Post by **04crewvt** » Sat Aug 30, 2008 5:09 pm

Synthetic it is. I have a required 500 mile oil change on the new motor then in goes the Amsoil I had just purchased everything for the scheduled change on the previous motor so I am all set there. YES I KNOW but I am a stubborn SOB and I am going to document every last bit of information that they want so that IF there's a problem again I will be ready. By the time the engine went up I had two to three types of oil in it as well as SeaFoam so I couldn't send a failure sample in to them to see if that was the problem. This time I am going to add the bypass filter and get the testing kits and see how that works out.

F9K9 · Post by **F9K9** » Sat Aug 30, 2008 8:19 pm

04crewvt wrote:............YES I KNOW but I am a stubborn SOB................

Sigh! With that said, we are in agreement.

04crewvt · Post by **04crewvt** » Sun Aug 31, 2008 4:13 am

f9k9 wrote:
04crewvt wrote:............YES I KNOW but I am a stubborn SOB................
Sigh! With that said, we are in agreement.

04crewvt · Post by **04crewvt** » Sun Aug 31, 2008 4:20 am

one thing I did note yesterday on the drive home is this engine has way more oil pressure than my old one ever did. The original motor cold had slightly over 40psi the new one is closer to 60psi also when warm and at highway speeds the new one is at 40-45lbs the old one would be at 25 or so. I wonder if the oil pump had been slowly going bad and that contributed to this issue as well?

04crewvt · Post by **04crewvt** » Sun Oct 05, 2008 2:54 pm

Less than 1000 miles in and code P0420 has reared it's ugly head again. I still thing the Cat is bad but since it was showing good flow the dealer didn't check it further or change it out. I will be calling to get it into the shop this week.

I am also still only getting 15.3MPG which is only .1 MPG better than the Tahoe with 211K on it. I was getting nearly 18 with the old motor before I started this whole mess in the spring with a basic tune up for gas mileage.

Post by **HenryJ** » Sun Oct 05, 2008 3:27 pm

Actually 15 mpg is closer to normal for city mileage.
18 mpg is closer to highway mileage.
Yes the Tahoe gets as good or better mileage. That has been my experience around here. The S-10 can get slightly better on the highway, but not by much.

04crewvt · Post by **04crewvt** » Sun Oct 05, 2008 3:36 pm

Mileage was at 17.8 with the exact same driving mix of 32.2 miles one way apx. 8 miles at city speeds the rest at highway speeds. After the problems started it dropped to the 15.3 range and nothing that has been done seems to change that, no change in driving habits, new fuel filter,pressure regulator, motor, plugs, wires,cap,rotor. Only thing that keeps cropping up is the P0420 code. Would it be out of line for me to get the cat changed out as well as the O2 sensors? could they have become fouled with all the misfires/coolant leak that were occurring with the engine failing?

Post by **HenryJ** » Sun Oct 05, 2008 3:45 pm

04crewvt wrote:Would it be out of line for me to get the cat changed out as well as the O2 sensors? could they have become fouled with all the misfires/coolant leak that were occurring with the engine failing?

Possible. I would shoot the cat for temperature differential between the inlet and outlet. It should be about 100 degrees.
Here is a site that shows some of the damage and causes of converter failures-
Magnaflow website - converter failure

Magnaflow wrote:CATALYTIC CONVERTER FAILURES:
If a catalytic converter needs replacing, one of the problems below most likely
contributed to its failure.

Engine Tune-Up Required.
A number of problems could occur to the catalytic converter as the result of an engine that is out of tune. Any time an engine is operating outside proper specifications, unnecessary wear and damage may be caused to the catalytic converter as well as the engine itself. The damage is often the result of an incorrect air/fuel mixture, incorrect timing, or misfiring spark plugs. Any of these conditions could lead to catalytic converter failure or worse.

Excess Fuel Entering Exhaust.
The fuel that powers your vehicle is meant to burn in the combustion chamber only. Any fuel that leaves the combustion chamber unburned will enter the exhaust system and light-off when it reaches the catalytic converter. This can super-heat the converter far above normal operating conditions and cause a meltdown. Possible causes are an incorrect fuel mixture, incorrect timing, corroded spark plugs, a faulty oxygen sensor, sticking float, faulty fuel injector or a malfunctioning check valve.

Oil or Antifreeze Entering Exhaust.
Oil or antifreeze entering the exhaust system can block the air passages by creating a heavy carbon soot that coats the ceramic catalyst. These heavy carbon deposits create two problems. First, the carbon deposits prevent the catalytic converter from reducing harmful emission in the exhaust flow. And second, the carbon deposits clog the pores in the ceramic catalyst and block exhaust flow, increasing backpressure and causing heat and exhaust to back up into the engine compartment. Your engine may actually draw burnt exhaust gasses back into the combustion chamber and dilute the efficiency of the next burn cycle. The result is a loss of power and overheated engine components. Possible causes are worn piston rings, faulty valve seals, failed gaskets or warped engine components.

Deteriorated Spark Plug or Spark Plug Wires.
Spark plugs that don’t fire, or misfire, cause unburned fuel to enter the exhaust system. The unburned fuel ignites inside the converter and could result in a partial or complete meltdown of the ceramic catalyst. Spark plugs and spark plug wires should be checked regularly and replaced if damaged or if wires are worn or cracked.

Oxygen Sensor Not Functioning Properly.
An oxygen sensor failure can lead to incorrect readings of exhaust gasses. The faulty sensor can cause a too rich or too lean condition. Too rich and the catalyst can meltdown. Too lean and the converter is unable to convert the hydrocarbons into safe elements and may not pass a state inspection.

Road Damage or Broken Hangers.
The catalyst inside a catalytic converter is made from a lightweight, thin-walled ceramic. It is protected by a dense insulating mat. This mat holds the catalyst in place and provides moderate protection against damage. However, rock or road debris striking the converter, or improper or broken exhaust system support can cause a Catalyst Fracture. Once the ceramic catalyst is fractured, the broken pieces become loose and rattle around and break up into smaller pieces. Flow is interrupted and backpressure in the exhaust system increases. This leads to heat build-up and loss of power. Possible causes of a catalyst fracture are road debris striking the converter, loose or broken hangers, potholes or off-road driving.

A catalytic converter will rarely fail without a problem or malfunction occurring somewhere in the emission system in front of the converter. It is important to determine what caused the converter to fail so that the problem can be fixed and to prevent a recurrence of the failure.

Converter Meltdown.
This is an example of a converter meltdown. The converter was super-heated due to a raw fuel condition in the exhaust flow. The excess unburned fuel ignited when it struck the hot ceramic catalyst and drove the temperature far above the normal operating condition of the converter. The ceramic catalyst is unable to withstand the extremely high temperature and begins to melt. The ceramic collapses and the converter is destroyed. The melted ceramic may block the exhaust flow and cause additional damage to the engine. A converter glowing red-hot, or evidence of heat discoloration, confirms this situation.

The condition that led to this converter meltdown could be the result of a number of malfunctions including faulty oxygen sensor, an incorrect fuel mixture, worn spark plugs or plug wires, a faulty check valve, incorrect ignition timing, sticking float, faulty fuel injectors or other ignition malfunctions.

Carbon Deposits.
This is an example of a converter with carbon deposits in the ceramic catalyst. This is usually a result of oil or antifreeze entering the exhaust system or a too-rich fuel mixture. The heavy carbon deposit clogs the converter and reduces exhaust flow. This increases backpressure and causes the entire exhaust system to heat up. The heat backs up into the engine compartment and may result in a number of heat-related engine problems.

Mild carbon scoring may do less damage to engine components but it may seriously affect the converter’s ability to reduce harmful emissions. It could easily cause a vehicle to fail an emission test.

Carbon deposits may be the result of faulty valves, worn piston rings, worn or leaking gaskets or lead in the fuel.

Catalyst Fracture.
This is an example of a catalyst fracture. The ceramic became loose, cracked and began to break down. The pieces began to obstruct flow, creating backpressure and increasing the heat in the exhaust system. There is evidence of a partial meltdown in this example due to overheating.

The initial cause for this damage could have been road debris striking the converter based on evidence of impact on the converter shell. In some cases, if the protective mat that holds the catalyst in place is directly exposed to exhaust gasses, it could deteriorate and allow the catalyst to fracture. The Car Sound converter uses two recessed cavities in the body to hold the protective mat out of the exhaust flow to prevent any deterioration. The mat stays in place and the catalyst is held firm.

Catalytic Converter - By Larry Carley

CONVERTER OPERATION
Under normal operating conditions, the converter should not have to work very hard to accomplish its job. If an engine has good compression, is not sucking oil down the valve guides, and the fuel, ignition and engine management system are all working properly, there should be relatively little HC and CO in the exhaust for the converter to burn (a few tenths of a percent CO and less than 150 ppm of HC when the engine is warm). In many late-model engines with multipoint fuel injection, combustion is so clean that the converter has little to do and the difference between the inlet and outlet temperature may only be 30 degrees F at 2,500 rpm which is a lot less than the old rule of thumb that says a good converter should show at least a 100 degree F difference fore and aft at cruise. At idle, the converter in many late-model vehicles may cool off so much that there's almost no measurable difference in fore and aft temperatures. So checking exhaust temperatures fore and aft of the converter at idle and 2,500 rpm may not be the most accurate way to determine if the converter is working or not.

One thing temperature measurements will tell you, however, is if the converter is working too hard. An infrared noncontact pyrometer or a temperature probe will tell you if the converter is running unusually or dangerously hot. If the converter outlet temperature is 200 or more degrees higher then the inlet temperature, it means the engine is running rich and there's a lot of CO in the exhaust that needs to be burned. A rich fuel mixture will often produce a "rotten egg" odor in the exhaust (the smell is hydrogen sulfide). Underlying problems may include an engine management system that is not going into closed loop (check the coolant and oxygen sensors, or for a thermostat stick in the open position), plugged PCV valve, or excessive fuel pressure (bad fuel regulator). High CO levels in the exhaust can also be caused by an inoperative air pump system.

If the outlet temperature is a lot hotter (more than 500 degrees F) than the inlet temperature, it indicates unburned fuel in the exhaust. The most likely cause would be ignition misfire (fouled spark plug, shorted or open plug wire, cracked distributor cap, arcing rotor or weak coil), or a compression leak (burned exhaust valve). But other causes may include lean misfire (check for vacuum leaks, leaky EGR valve, low fuel pressure or dirty injectors). A single misfiring spark plug can cause an increase in HC emissions of 2,500 or more parts per million, which can push the converter's operating temperature well above its normal range.

A common external clue of overheating to look for is a badly discolored or warped converter shell.

04crewvt · Post by **04crewvt** » Thu May 28, 2009 5:41 pm

Shipping the Crew to the stealership in the next few days to get it back up and running. Parked it last fall with only 1000 miles on the new motor when the ABS brake light kicked on and the p0420 code came back. The truck won't pass inspection with these and this time I am going to point out to them that if the code keeps coming back they need to honor the emissions warranty and change the cat. They flat out refused to admit it was a problem last fall. My Optima red top drained twice this winter just sitting so not sure if it is on it's way out as well it's only 2 years old and has dropped to as little as 3v this last time. Have taken it in for replacement but with a charge on it they say it's fine. As much as I love this truck I might ditch it if I could find something that gets better gas mileage that I fit in and would not have a payment. Not really looking just getting frustrated.

04crewvt · Post by **04crewvt** » Mon Jul 13, 2009 10:19 am

Finally got it in today. Stealership says another $1000 to get it inspect able. Bad idler arm ( again, had one replaced under warranty 24K), hub bearing(only a little over a year old) plus leaking oil lines, I don't think they need to change them to inspect it. They wanted to have me flush and drain the Transmission but I just had that done 1500 miles or so ago and the brakes show some pitting on the rotors from sitting all winter but they will pass, add an oil filter lube since it's up in the air and I should be good to go. The P0420 code is not showing up today so they will inspect as is and if it comes back we will see what is wrong., they wanted too much for diagnostic time to drive it around and see if the light would come back on.

Reed I think your ducks have found a permanent site right over my hood.

F9K9 · Post by **F9K9** » Mon Jul 13, 2009 3:11 pm

I hate to hear that, bro!

04crewvt · Post by **04crewvt** » Sat Sep 05, 2009 11:50 am

After another 100 miles the P0420 finally set again, took it back in and dealership reluctantly agreed to replace Cat under warranty. Waited a week to get part in and another to get it down to the dealer to be worked on, a third to get it back (switching back and forth from night to day shifts for work sucks). With any luck the code will be gone for good.
They tried to hit me with a big bill for labor tracking down a parasitic drain on the battery that had again drained the brand new Optima Red Top. They think it was the scanguage being plugged in all the time but Scanguage says it only draws 2miliamps when off. Anyway they were a little annoyed when I thanked them for all their free diagnostic time since I had not authorized them to spend any time on doing anything but the warranty repair. Got out with only $45 in shop fees for them charging the battery and labor in getting it off the wrecker I had shipped it down on (AAA saves the day again)

S-10CREWCAB.NET

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