MAF Sensor mod problem

F9K9 · Post by **F9K9** » Sat Oct 08, 2005 11:22 am

Okay, went on a "beer run" this afternoon (I know what you're thinking but, it's still in the fridge getting cold)

and on the way back (110 miles round trip) I threw another code.

My IAT is in front of the MAF and it is in the 50°-60°F range here. Is my 180° T-stat going to be a seasonal thing?

Post by **HenryJ** » Sat Oct 08, 2005 11:43 am

f9k9 wrote:... I threw another code. ..

What code did it throw? Are you using a Hypertech thermostat that has the bypass valve?

You can't assume it is the thermostat automatically.
It has been freezing here nights and I haven't had any problems.

F9K9 · Post by **F9K9** » Sat Oct 08, 2005 12:07 pm

Disregard Brule! I assumed again and I know better. When the SES kicked on I glanced at the gauge and assumed it was Temp related.

My Bad

and I apologize

It's P0101 and must be related to the MAF mod unless there is a chance I put to much oil on the Airaid filter which I doubt. I was pretty conservative.

Am using the Jet thermostat that I first found in the "MOD" section of the home page when I found on the site.

Post by **HenryJ** » Sat Oct 08, 2005 12:25 pm

You're right the Jet stat is the right one. Hypertech was the 160* stat. My memory must be going

Looks like there is some work to do on the MAFS mod

F9K9 · Post by **F9K9** » Sat Oct 08, 2005 12:32 pm

HenryJ wrote:You're right the Jet stat is the right one. Hypertech was the 160* stat. My memory must be going

Looks like there is some work to do on the MAFS mod

I've not researched it but, I do not think the code has anything to do with the possibility of the sensors being contaminated, am I correct on that one?

Post by **HenryJ** » Sat Oct 08, 2005 12:38 pm

Looks to be a calibration error.
The preset map doesn't match the readings taken and the PCM is unable to compensate beyond its programming.

You may need to alter the PCM to match the MAF sensor?

That is all just a guess since I have not really gone into this stuff in depth.

Skewed readings from dirty sensors can effect this I'm sure. I'd check them.

F9K9 · Post by **F9K9** » Sat Oct 08, 2005 12:48 pm

Will clean the sensors tomorrow. I should have known something was amiss when I fueled up today.

The MPG was so bad that I will not even share it and I have been a model blue haired lady driver.

If I was to post it in any S-10 forum I am sure I would have the worst ever mileage for all recorded history!

No, I ain't posting it!

killian96ss · Post by **killian96ss** » Sun Oct 09, 2005 10:40 am

I posted this on another MAF topic, but here is the info again.

Cutting out the cross piece on the MAF will do nothing for power on a stock V-6. You would have to be pushing at least 360 hp before the stock MAF starts becoming a restriction, and those are the specs for a V-8. On a V-6 it would be more like 400 hp. I doubt anyone here is near that level, even with a supercharger. The only thing that will happen from removing this cross piece will be the engine running a little lean which will be corrected by the computer within 50-150 miles. The stock MAF is also programmed to run within a certain airflow parameter and could run on the edge of it's tuning which might cause air/fuel ratio problems. When you remove this cross piece you are altering the amount of air flow over the sensors and the computer will read this as an error and possible set the SES light. There is a reason why it's there.

The aftermarket MAF's that you see without the cross piece have been custom programmed to compensate for the increased airflow. f9k9, I am only reposting this info because I see you are having a problem which might be related to the MAF mod that you did.

I have seen way too many guys in our B-body club as well as the Camaro guys try doing this mod with bad results.

Steve

F9K9 · Post by **F9K9** » Sun Oct 09, 2005 11:33 am

Steve,

You did post exactly that in another thread and I stated that you were probably correct and that it was a mod that kept me busy one weekend and to only spend $20 and occupy a weekend, it was pretty cheap?

I've had bar tabs 10X that amount and had nothing to show for it. I ran it for probably 600 miles before the SES light . The stock MAF is back in it and I have learned a lot about MAFs, and my new Dremel tool. Not bad for 20 sawbucks and your advice is always welcomed

killian96ss · Post by **killian96ss** » Sun Oct 09, 2005 6:13 pm

f9k9, if I had not seen others fail with this mod, then believe me I would have tried it also. I love cheap mods as much as you, especially if they just give you something to do. I'm surprised that you made it 600 miles before your CC alerted you to the problem.

Here is some info from Jet & Granatelli that is simply not true. The first quote is from Jet's web site.

The factory sensor not only is a major restrictive point in stock intake systems, but it also limits the full potential of aftermarket cold air intake systems.

BS, the factory MAF is nowhere near a restriction on a stock engine. While it is true that an aftermarket air intake can flow more air than the stock MAF, remember that this means nothing since a stock engine can only draw a certain amount of air which the stock MAF is more than capable of doing.
The second quote is from Granatellis web site.

Does the computer relearn the fuel and timing curves canceling out any performance gain?
No. GMS mass airflow sensors are "truly calibrated" on our proprietary computerized flow benches and plays no tricks on the factory ECM/PCM.

What are the disadvantages of home porting or larger aftermarket billet ends?

They are for off-road use only.
They are not calibrated so the factory computer will “learn out” these modifications after 200 miles negating any performance increase
They cause the engine to run lean

The only solution is to use a "truly calibrated" mass airflow sensor from Granatelli Motor Sports.

Even more BS. First of all "truly calibrated" just means that they calibrated the sensor to match it's increased airflow. The computer will still "learn out" the performance MAF the same way it "learns out" a modified stock sensor. So what you end up with is a stock style sensor that can flow more air even though the a stock engine doesn't need it. The second thing worth noting is that both companies do it fact dyno cars and trucks with their sensors installed and get hp & torque #'s that are higher than stock, but what they are not telling you is that once again the computer will "learn out" this new found power and when it does your vehicle will basically return to it's stock #'s. The reason for this is simple. When they do a dyno test they install the new sensor and test it immediately before the computer has a chance to relearn the correct settings. The reason they are getting more power is because the engine is running on the lean side which will make more power, but it will also cause major engine damage, which luckily will be corrected by the computer. In the end all you end up with is a lighter wallet to the tune of almost $400.

Another thing worth noting is that most aftermarket MAF's can't be used with hand held programmers like the Hypertech because they will cause pinging or detonation problems due to the different timing and fuel tables that the aftermarket MAF is not calibrated for. Everything that I have stated above is not just my personal opinion, but rather information that I have learned from several other forums from people who found out the hard way that these high flow aftermarket MAF's really don't work that well unless they are installed on a highly modified engine which also has custom computer programming to match the MAF.

Steve

F9K9 · Post by **F9K9** » Mon Oct 10, 2005 3:22 am

Really good info

Thanks for taking the time

Horsehammerr · Post by **Horsehammerr** » Wed Sep 26, 2007 12:05 am

I had the P0101 code set on my '02 ZR5. I cleaned the MAS with CRC MAF cleaner, the Throttle Body with CRC TB cleaner ,added a K&N filter to my HJ modded airbox, and cut , ground, buffed out the stiffing ribs from inside the top filter cover. I hoped this would help with smoother intake air flow. At first the SES light was off and it seemed to run very smooth and responsive. The only problem I am having now is that SES light keeps coming on in the afternoon on my drive home. Anything I should check ? I will check the code tonight. Thanks

F9K9 · Post by **F9K9** » Wed Sep 26, 2007 1:07 am

I know that too much oil on the K&Ns will toss a MAF related code but, don't know which one for sure.

GM Data wrote:DTC P0101
Circuit Description

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits:

* An ignition 1 voltage circuit
* A ground circuit
* A signal circuit

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. The PCM uses the following sensor inputs in order to calculate a predicted MAF value:

* The manifold absolute pressure (MAP)
* The intake air temperature (IAT)
* The engine speed (RPM)

The PCM compares the actual MAF sensor frequency signal to the predicted MAF value. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. DTC P0101 sets if the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value.
Conditions for Running the DTC

* DTCs P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0121, P0122, P0123, P0335, P0336, P0401, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1111, P1112, P1121, P1122, and P1441 are not set.
* The engine is running.
* The ignition 1 signal is between 11-18 volts.
* The throttle position (TP) sensor angle is less than 95 percent.
* The change in the TP sensor angle is less than 5 percent.
* The MAP sensor is less than 80 kPa.
* The change in the MAP sensor is less than 3 kPa.
* The above conditions are met for 1.5 seconds.

Conditions for Setting the DTC

The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds.
Diagnostic Aids

Inspect for the following conditions:

* An incorrectly routed harness. Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
o The secondary ignition wires or coils
o Any solenoids
o Any relays
o Any motors
* The throttle plate for sticking, or for deposits on the throttle plate or in the throttle bore.
* A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
* A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 130 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
* The barometric pressure that is used in order to calculate the predicted mass air flow value is initially based on the MAP sensor at key ON. When the engine is running the MAP sensor value is continually updated near wide open throttle. A skewed MAP sensor will cause the calculated mass air flow value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
* A high resistance on the ground circuit of the MAP sensor may cause this DTC to set.
* Any loss of vacuum to the MAP sensor may cause this DTC to set.
* A high resistance in the ignition voltage circuit of the MAF sensor may cause this DTC to set.

If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.

If the condition is intermittent, refer to Intermittent Conditions .

Intermittent Conditions

Checks

Action

DEFINITION: The problem may or may not turn ON the malfunction indicator lamp (MIL) or store a diagnostic trouble code (DTC).

Preliminary Checks

Refer to Symptoms - Engine Controls .

Damaged Electrical Connections or Wiring

* Carefully reform all the connector terminals in the problem circuit in order to ensure the proper contact tension. If necessary, replace all the connector terminals in the problem circuit in order to ensure the proper contact tension. Refer to Connector Repairs in Wiring Systems.
* An intermittent may be caused by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation.
* Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.
* If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Road Test

* If a visual and physical check does not locate the cause of the problem, drive the vehicle with a DMM connected to a suspected circuit or use a scan tool.
* When the problem occurs, an abnormal voltage or scan reading indicates the problem may be in that circuit.

Intermittent Components

The following components can cause an intermittent:

* A defective relay, control module driven solenoid, or a switch that can cause an electrical system interference--normally, the problem will occur when the defective component is operating.
* The improper installation of electrical devices, such as lights, 2-way radios, electric motors, and other devices.
* Route the ignition control (IC) wires away from the spark plug wires, the ignition system components, and the generator. The wire for the engine ground from the control module to the ignition system should be a good ground.
* The ignition secondary voltage shorted to a ground
* The malfunction indicator lamp (MIL) circuit or the diagnostic test terminal intermittently shorted to a ground
* The control module grounds