I know this has been debated through a lot of posts but they all seem to stop with anything conclusive. I went through all of them and I am still stuck with this Code 34 on my MAF system which would equate to "MAF Sensor Low" according to my Tunerpro.


I checked the following:
- Operation of the MAF Power Relay and MAF BurnOff Relay both in and out of the circuit
- Continuity throughout all the MAF Related circuity from the ECU to the MAF Connector to the MAF Relays
- Power to the MAF Sensor when Relays are actuated
- Cleaned the MAF sensor using mild alchohol spray
- Vacum leaks within the inlet plenum. I blocked off anything which is not connected for the timebeing (Charcoal Cannister vacum and Cruise Control Vacum)
- All of the hoses are fully secured


The MAF itself has had the screen removed by the PO however both the thick wire and the thin hair size wires are fully intact and clean. On the bottom there is a sticker that says Remanufactured with a GM brand.


The car itself runs fine idle seems stable however from the exhaust smell I think it is running quite rich. Even tunerpro is indicating Rich in the Item list called "Lean/Rich".

I also have Code 32 "EGR Diagnostic" on however I will get rid of the whole EGR thing soon as I will program a PROM without EGR checks. Have also removed a custom ROM by the PO and am now running stock memcal.

How sure should I be to buy a new MAF considering I do not have anyone who can lend me theirs to try as these are are not common here where I live? Also do I have to buy the GM genuine ones or perhaps someone has tried other brands with success? These sensors are quite expensive!!

Did anyone ever try to fit a MAF from another car / model perhaps it is cheaper?

 

With the maf disconnected the ecm should see a maf high and set a code 33. If a code 34 throws the ecm or wiring is faulty.

 

Disconnected the Maf while engine was running and it almost died then recovered. I also got code 33. I think this means maf is actually working...

 

I'm sure you have already gone through this diagnostic flow chart.
http://www.chevythunder.com/maf_code_34.htm
a rough idle can cause the code 34 too. I don't know for sure but in limp home mode this might throw. I think having the code 32 might cause limp home mode. A service manual I have says the code 34 will only throw if rpm is above 2300 in neutral with 6% tps reading. Typical gps for idle is 7-9 increasing with rpm .sounds like maybe a bad maf you can watch the gps on to the code 34 will set at 2.5 gps.

 

Thanks for the info. You think that the egr ses is placing the ecm in limo mode and in turn throwing code 34?

I will burn a stock PROM without EGR and see what happens

 

I was thinking it could be possiable if the idle is real bad rich running.

 

Will try it out and let you all know.