Computer Gurus please... MAF G/s

[Kyle F]

Theoretically, how does our computers compensate for boost? It does it by leaving the 14.7:1 AF ratio down to a 13:1 12:1... etc right?


Well, what if your TPS is reading WOT Voltage close to 5V, but the MAF is only reading 252-253 G/s?

BUt the WTO O2 Voltage seems to stay up in the 800mV range. Or, waht if the O2 mV's dont stay that high?

What does it mean if the MAF is not reading 255G/s ?

 

[Kyle F]

Anyone have any clues?

 

[TurboDave]

Depending on the boost you're running, not being able to hit 255 may not meen anything. Keeping the boost down around 14-15# may not top the MAF out until late into the run, if at all. As the boost levels increase though, it should hit 255 easy and early! Otherwise it may be a good time to start hunting for a better one.

 

[Kyle F]

Well, I am gettin boost spikes up into the 18# range. But never see the MAF at 255.

I am trying to figure out if I have abad ECm or not. I have eleminated so much other stuff.

 

[Warped]

I had a maf that never read above 230. Replaced it with the lt1 and translator plus and now ds shows maf numbers way over 255. Try another maf.

 

[TurboDave]

Originally posted by Kyle F
Well, I am gettin boost spikes up into the 18# range. But never see the MAF at 255.

I am trying to figure out if I have abad ECm or not. I have eleminated so much other stuff.

I noticed in your sig. that you mention a "modified" MAF. That could be the point of contention. Who modified it? what did they do? What did they start with, a brand new GM unit, or a remanufactured unit.

Did this just start doing this, or is it something you're just now paying attention to??

 

[Kyle F]

I did it. Old TPI trick. I have doen many of them, started with an OEM GM unit. Worked fine for a long time. almot a year and a half.

the funny thing was the car sat for a few months not moving a whole lot, couple of dead battery charges before the Knock problem started. Infact, it was even after I got the gage pods installed, was running the same boost, etc. This problem just came out of now where.

I started to suspect that the MAF might be going bad, as a lot of people seem to thing that the ECM shouldn't be the problem. Though, I am getting random bad frames of data in Turbo link, and odd trouble codes.

All grounds have been checked, cleaned, and reinstalled. Coil Packs tested bad, and were replaced with units that were tested before installation. The Ignition Module was tested good, Wires were replaced, Plugs replaced (Stock type AC R42LTS). Plus got a new O2 sensor as well.

I have cut the heat sinks out of many MAFS on multiple TPI cars that are all still working, some have been running modified since 1996.

I tap tested the MAF, just to make sure. No stumbeling.