i have a MAF TPI with 1227165 ECM on a 5.7L engine, everything stock (it's a 87/88 setup with cold start injector), which is not really running. if i start the engine, it fires some times, and then dies too rich.

i checked that in TunerPro RT using the ALDL8192 (to see a fluent graphical MAF value), and noticed, that at Key ON/engine OFF the MAF value is always 23 gr/sec, and when i crank the engine it seems to show the true value. i don't know if this is normal, but i thought if i blow some air through the MAF, it should show me something, even in Key ON/engine OFF, isn't that true?

i guess, the MAF value is too high, so the ECM injects too much fuel - but how can i go on if it's not the MAF sensor? actual i'm using a 86 MAF, does that fit to the 87 PROM/calibration?

i already replaced the MAF, the fuel-injectors and the ECM.


i have a datalog from TunerPro RT, if somebody might want to take a look at it, i could post it here.

 

The chances of two MAFs being bad are very slim. It's probably almost a rare as an ECM failing.

The '86 MAF should work on all TPI systems through the 1989 models - They are the same part.

TunerPro may be reporting a 23g/S flow with the engine off, but the MAF should have almost no output from its 'C' terminal.

A more important consideration is the PROM/calibration you are using. Do you know what the factory code is, or is it a custom?

 

i tried different PROMs - the stock one from 87 (ABWN), and some self-made-PROMs, where i tried using bin's from 86 to 89 - the problems are nearly the same with every chip

since i tried 4 different ECM's (one of them was a new, not a rebuilt, one), i don't believe there is a faulty part - i guess there is any kind of incompatibility issue

i think my next step will be to take a ECM AND MAF sensor from a running car, and try them together on my car, to see if my problem is at those parts or anywhere else

 

[Ghost of TPIs past] Make sure to inspect the relays...[/Ghost of TPIs past]

 

they are all new and in a new painless harness. but i will check them outside on my desk if they work how they should

 

Little No,

try to test the MAF itself with a power supply on your desk and check the output voltage with a dvm.

Btw: you have a PM

Greets

Jens