Canadian Hummer Club Forums

hey guys



about two weeks ago i had a service engine light come on and it was a mass air flow circuit performance code.

i didnt think much of it and cleared the code. its came back a few times now. the truck is still kicking the code but now there is a fuel bank rich bank 1 and 2.

by this point it is running horrible. its like it floods it self





ive tried to clean the MAF still no. so i replaced the MAF and still no.

so my mechanic buddy took a look at it last night all my wires at the sensors are reading correct.



after we hooked up the diagnostics machine i fount out that the MAF reading is multiplying as you increase the rpms. and due to the fact it thinks its getting so much air its supplying that much fuel .





ex. desired MAF reading was 18g/s and it was reading 165g/s

idle is fine but as soon as you touch the throttle it starts







what can make the this sensor read that far out.



to me it seems like a computer problem. i think i might try to get a reflash the computer next cause its burning threw a tank of fuel in 250kms



OUCH

<img src='http://www.canadianhummerclub.com/forum ... ngHead.gif' class='bbc_emoticon' alt=':banghead:' />









seriously any help would be great



thanks



brian

Stumped on this..... Hate to say it but I'd say run it by Rick.... He knows his hummers.....

Change your intake manifold gaskets and your two knock sensors in the engine valley.



I have had this happen before!



Also, you could have gotten bad gas...I had that happen before also!

ive ran threw 2 tanks of fuel and within 6-8mnths knoc sensors and gasket were changed. wouldnt that give me a lean code and not rich fuel. and the maf is reading way to high

Seeing as that has been done,let me research a bit and I will let you know!

Maybe try cleaning the connector on the sensor or something dude, those are just 5 volt analog sensors far as I know and if it's really reading high like that maybe it's a short or something, as I'd bet it's pinned at 5 volts?

so after a few more hours of trouble shooting me and a few mechanic buddys came to the conclusion that its a computer fault



thank god for the good guys down at erols automotive there going to do a computer flash for me and see how many updates the truck has missed over the years



i really hope this solves my issue. and i will keep you guys all posted











please kev if you have any more possibilities i am all ears









there is a 5v low reference in that harness as well as a 12v everything is where it should be.



were thinking the computer is feeding incorrect info too the maf sensor since everything looks right except the maf reading witch is causing it to dump fuel into the motor like its going out of style



and to top all of it for giggles i pulled the programmer and no differance how ever about 45 min afterwords truck wouldnt even turn over not even a spudder. it had all power but nothing when i tried to turn it over to start it. about 20 min later it was if nothing happened. and of coarse it runs like crap again. lol <img src='http://www.canadianhummerclub.com/forum ... ngHead.gif' class='bbc_emoticon' alt=':banghead:' />







im totally thinking the computer

OK, if it is doing stupid stuff like that try this;



1. Disconnect both battery cables

2. Hold both the positive and the negative cables together (not touching the battery only cable to cable)

3. Wait three minutes and then reconnect the cables

4. Start and try the truck



What this does, is if it is a computer fault, it wipes the memory back to zero and forces it to run on it's basic set-up and normally removes phantom problems.



Try that while I keep researching!

Ok, after some research I need you to tell me the following;



1. What is the voltage of the MAF? You should be between 0.7 and 0.9volts

2. What is the engine load at?

3. What is the MAP sensor reading?

4. Did you try disconnecting the MAF? Does the engine run better or worse?

5. What are you O2 sensors reading?



Let Me know and I should be able to pinpoint the source of the problem.

ok

i cleaned the throttle body again and put the stock intake tube back on and my jet perf maf. the maf code never came back but now just rich codes

everything is running and working now tho seems to run fine anyway



i have no idea what to do next.



long term is 11 and on cell 17.







map sensor is good aswell as the maf.

all wires are good no loose pins at the ecu





the trucks runs fine now just runs rich.





kev would there be any chance a ground would fault and cause this intermittent problem?





i am so lost with this thing