Joined the club! *Fuel Pump Module Problems

border man · Post by **border man** » Sat Nov 17, 2007 7:40 pm

Well after almost 7 years and 103,375 miles, I have finally joined the erratic fuel guage club.

I was driving home today, and had 1/2 a tank of gas when I got off the highway. As I pulled into my driveway (5 miles) my low fuel light went on and off, on and off, and the needle was just above "E". It also jumped around quite a bit. I there any other possible fixes other than full replacent of the sending unit, ie.. loose ground at the tank?

F9K9 · Post by **F9K9** » Sun Nov 18, 2007 4:08 am

Start using your trip odometer of maybe a can of Sea Foam. My '97 was locked on full for a yr or two. The Sea Foam freed it up but, was never correct again. I'd say count your blessings for over 100K of good use out of it.

adrenalnjunky · Post by **adrenalnjunky** » Sat Dec 29, 2007 2:42 pm

My 2000 model started doing the same thing at about 70,000miles.

I'm assuming this is a sending unit in the tank that needs replacement?

Post by **HenryJ** » Sat Dec 29, 2007 2:49 pm

That would be a good guess. The pump quitting may be the next symptom you experience.

04crewvt · Post by **04crewvt** » Sat Dec 29, 2007 2:53 pm

My co-worker at work has a 2001 blazer whose gas gauge had been erratic for a while. He had had a couple of hard starts a few weeks ago and when he asked what I thought was up I looked at these threads and prepared him for the worst and sure enough 3 weeks before Christmas a new fuel pump and sender were installed to the tune of nearly $800.00 at the stealership.

green02crew · Post by **green02crew** » Sat Dec 29, 2007 5:52 pm

Mine only worked for about 3 months after I got the truck. Truck only had 40k on it when the gauge started freaking out so I had to learn how far I could get on a tank. Now its on empty with low fuel light 24/7. Never had any other problems with it though *knock on wood*. Once I saw how much it would be to repair I decided it wasn't much of a hassle to reset the trip every fillup.

roadrunner · Post by **roadrunner** » Sun Dec 30, 2007 10:49 am

Okay, now you guys are scaring me!

My 01 CC had 59k when I got it and guage worked fine. Lately has started going nuts. Other day was reading about 1/4 ti 1/8 then started bouncing around and low level light came on. And no I wasn't off road'n so gas wasn't going from bottom of tank to top and back.

Then guage dropped below E peg and stayed there.

I was in town so went to station and filled up. Only took 15 gallons so was still about 1/4 full more or less. I suppose this means my pump and sender are getting ready to c--p out?

04crewvt · Post by **04crewvt** » Sun Dec 30, 2007 1:02 pm

As far as I know our all crews have a 16.1 gal tank, if that's the case you were almost empty which is what causes many of the problems to start with the senders. I try never to go much below 1/2 tank.

roadrunner · Post by **roadrunner** » Sun Dec 30, 2007 7:27 pm

Can't speak to your trucks but owners manual lists my 01 crew cab as 19.0 US gallons. I have put in slightly over 20 on a couple occasions when I got caught with my pants (fuel guage) down. It is common for vehicles to hold slightly more than the manual lists if you fill them clear to the fuel cap. I also try not to run too low on gas as I know the value of keeping the pump cool and the fuel is its coolant.

Post by **HenryJ** » Sun Dec 30, 2007 7:47 pm

I never get below half a tank. The specs on our website list the capacity at 18 gallons. Ex cabs list in the owners manual at 18.5 gallons. Someone said 17.5 gallons was the right answer. Don't forget that there may be a difference between the earlier models steel tank and the latter with the plastic. I am sure we have been through this all before. I don't think there was a good answer that time either

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Dec 30, 2007 10:36 pm

my 2001 has a 17.5 gallon tank, how many mpg/mpt do you guys get?

Torskdoc · Post by **Torskdoc** » Sun Dec 30, 2007 11:34 pm

Look at the shape of the tank. Long, FLAT, without a lowered sump. Any volume of gas is going to be spread out along the whole length and width of the tank. our tank is approx 18" wide, 4' long and 12" tall, lying on it side. 4 gallons will cover MAYBE about 3 inches deep. HOWEVER there appear to be NO baffles transversely in the tank to keep the gas from sloshing around. This is why your gauge will bounce around when you make turns, accelerate, or stop hard.

With the "sensitivity" of out gauges to STICK @ low fuel levels, you could have anywhere from 0 to 4-5 gallons when it sticks, and or fuel light comes on . The shape of the tank and the lack of baffles in the tank in GM vehicles have been a sore point with me for over 40 years. Even with a so called "RING" around the sending unit, you get sloshing and variations.

one positive solution to this is to remove the tank send to a tank shop and have baffles installed. Another is to install a fuel cell, or a tank with a different design.

Short of doing nothing and living with it, there is no cheap / inexpensive way to correct this problem. Adding a can of seafoam to the tank every 1000 miles for 5000 miles will help clean off the rheostat contacts on the levelometer to minimize sticking. Then add a can once a year.

According to the manual, CC's have a 18.5 gallon tank. I ran mine down to killing the engine and put in 18.7 when the nozzle tripped off.

I usually run 180-190 and put 15-15,5 gals.11.5-12mpg. This was b4 cap and rotor. Last fill was 230 and 14.4 gal. 15.97mpg

My suggestion would be to fill up when you start to feel uncomfortable based on combination of mileage and fuel level. Put more faith in the mileage, as you know how far you go on a tank for city or mixed or hwy driving.

Larry

04crewvt · Post by **04crewvt** » Mon Dec 31, 2007 3:12 am

Well I double checked the specs on the 2004's and it lists the gas tank as 17 gal I must have gotten the 16.1 from the most I have ever squeezed into it from reading empty. This was before I had found this site and realized how much of a no no that is. The best mpg I have ever gotten was about 19.2 on the highway in cruise control the worst about 15.5 in 4-wheel drive commuting to work in a snowstorm. I average right around 17 most of the time

F9K9 · Post by **F9K9** » Mon Dec 31, 2007 4:18 am

My '02 specs say 17.8 gallons

04crewvt · Post by **04crewvt** » Mon Dec 31, 2007 4:33 am

Seems like each year the used a different size tank is yours a metal tank? Mine is plastic.

mjmcdowell · Post by **mjmcdowell** » Mon Dec 31, 2007 8:56 am

Ok.....other than the obvious, what the heck is "seafoam" what is it, what is it's use(s), where do you get it? Oh!!! and HAPPY NEW YEAR everyone, stay safe, mjmcdowell

Post by **HenryJ** » Mon Dec 31, 2007 9:10 am

mjmcdowell wrote:what the heck is "seafoam" what is it, what is it's use(s), where do you get it?

Seafoam
I buy it at my local NAPA

roadrunner · Post by **roadrunner** » Mon Dec 31, 2007 12:20 pm

HenryJ wrote:I never get below half a tank. The specs on our website list the capacity at 18 gallons. Ex cabs list in the owners manual at 18.5 gallons. Someone said 17.5 gallons was the right answer. Don't forget that there may be a difference between the earlier models steel tank and the latter with the plastic. I am sure we have been through this all before. I don't think there was a good answer that time either

My Crew cab has the steel tank with the dip toward the front end and the plastic rock protector around the bottom and front. My manual says "regular and ext cab is 18.5 us gal and crew cab is 19.0 us gal". As I said earlier it will hold more than that if I fill it clear to the cap.

Rebel-Chevy · Post by **Rebel-Chevy** » Mon Dec 31, 2007 5:29 pm

my 2001 has the steel tank, the window paper from the original owner says 17.5 gallon tank, i think i get about 200 miles a tank which is about 13 mpg. 2 weeks ago i was leaving advanced auto and noticed the gas gauge was spiked to full, it stayed like that for about a week. within that week i filled up twice then the gauge dropped to E for about a week and now it seems to be working but i think its like a quarter of a tank off.

roadrunner · Post by **roadrunner** » Tue Jan 01, 2008 7:57 am

Yup, I still have the window sticker too and it also says 17.5 gal. However the manual that came with the truck says 19.0 and my experience more closely matches that figure. Lately I've been getting around 13.0mpg for all stop and go driving in 10-25 degree weather and 15-16mpg hiway in same temps. Not great but I can live with it.

My guage usually behaves pretty well till it gets down near 1/4 tank that's when it gets squirrelly

and when I said earlier it dropped to below E and stayed there it had been sitting still for 20-30 minutes on the level and after startup didn't move from there until after fillup.

drperry · Post by **drperry** » Tue Jan 01, 2008 2:37 pm

GM also sells a fuel system treatment that's supposed to clean the sending unit... Or help it last a little longer, at any rate... Tossing it in every oil change is supposed to help the sending unit last longer...

But from what I've been able to tell, Seafoam or the Luca Fuel System stuff are about the same... Though the GM stuff is reportedly slightly more aggressive at cleaning the sending unit.

killian96ss · Post by **killian96ss** » Tue Jan 01, 2008 6:03 pm

A little Marvel Mystery Oil in the gas seems to help free up the sticking fuel sender and offers more protection for the pump.

Steve

drperry · Post by **drperry** » Tue Jan 01, 2008 6:06 pm

Marvel Mystery Oil?

That's a new one, lol.

That's something I'd try just because of what it's called!

Now to find some...

killian96ss · Post by **killian96ss** » Tue Jan 01, 2008 6:13 pm

drperry wrote:Marvel Mystery Oil?

That's a new one, lol.

That's something I'd try just because of what it's called!

Now to find some...

Marvel Mystery Oil

Steve

drperry · Post by **drperry** » Tue Jan 01, 2008 6:20 pm

Sweet! Something that might actually be availiable in town! lol

green02crew · Post by **green02crew** » Tue Jan 01, 2008 6:21 pm

I get mine at walmart and yeah it does help sometimes with my erratic fuel gauge.

drperry · Post by **drperry** » Tue Jan 01, 2008 6:24 pm

My walmart probably doesn't have it... The Canadian versions of most US chains usually get hosed on the good stuff :p

roadrunner · Post by **roadrunner** » Wed Jan 02, 2008 7:57 pm

killian96ss wrote:A little Marvel Mystery Oil in the gas seems to help free up the sticking fuel sender and offers more protection for the pump.

Steve

Hey Steve, thanks for the reminder. Been so long since I used any Marvel I'd completely forgotten it.

Used to use it all the time to lube air impacts and air drills. Guess I've just been outta the shop too long! BTW unless they've stopped carrying it NAPA stores should have it also.

philippe · Post by **philippe** » Fri Jan 04, 2008 7:23 am

i have the 2002 cc and bouth it at 35 000km.the fuel guage was bad,i send it to gm dealer,they change some pieces and didnt change my truble.when my guage show me empty i put it on park and see the level go up.

roadrunner · Post by **roadrunner** » Fri Jan 04, 2008 8:29 pm

Just a little side note on the Marvel Mystery Oil. I don't know what they put in it

but I've always run a high quality fuel conditioner. However, since adding the "Oil" to the gas my gas guage appears to be behaving better

and I am now averaging a little over 14mpg instead of high 12s to low 13s.

I am currently on my 4th tankful with the "Oil" in it as well as my usual fuel conditioner. This may not sound like much to some but on a weekly basis it amounts to about twenty bucks saved in comparison to before. Doesn't take long to add up at that rate.

green02crew · Post by **green02crew** » Fri Jan 04, 2008 8:51 pm

Yeah when I first used it I got a slight increase in mileage, I stopped using it and the mileage didn't decrease but stayed the same. I went from the same about 13mpg to 14-15ish. I'm thinking it maybe acts as a fuel system cleaner? Who knows whats in there but it did also help with my gas gauge for a while but now I think its completely froze up and shot since it hasn't worked since the summer months.

Horsehammerr · Post by **Horsehammerr** » Sat Jan 05, 2008 12:41 am

Killian96ss: Just wondering what ratio is of MMO per Gal. in my CC tank. I don't want to smoke out the guy behind me.

killian96ss · Post by **killian96ss** » Sat Jan 05, 2008 12:45 pm

Horsehammerr wrote:Killian96ss: Just wondering what ratio is of MMO per Gal. in my CC tank. I don't want to smoke out the guy behind me.

I don't have a bottle to look at right now, but the ratio is listed on the bottle if you find some.

MMO is a fuel system cleaner and conditioner.

Steve

Post by **HenryJ** » Sat Jan 05, 2008 1:14 pm

Turtle wax website wrote:Use 4 ounces of Marvel Mystery Oil® for every 10 gallons of fuel.

border man · Post by **border man** » Sat Jan 05, 2008 3:15 pm

I've been using it every few fillups and it seems to work when I do. As far as mileage goes, never noticed an increase until I got to Roswell and started using 86 octane fuel.

roadrunner · Post by **roadrunner** » Sat Jan 05, 2008 7:27 pm

Yup, the bottle says 4oz per 10 gallons. Interesting thing though, I've only been using 2oz per 10 gal and do measure fairly carefully. Mileage is staying steady at 14 or a little more stop and go so I'm happy.

S-10CREWCAB.NET

Joined the club! *Fuel Pump Module Problems

Joined the club! *Fuel Pump Module Problems

"Seafoam"............????????

Re: "Seafoam"............????????