I put together a MAF system using mostly 1989 Camaro 5.7 MAF system (1227165 ECM) with painless wiring harness & Accel throttle body with 4 36# injectors. Been calibrating it using the APU1 and TunerPro RT. All is going adequately except I have not beem able to tune out a dead spot under light tip in usually about 25 mph (30 grams/sec air flow). I have a Motec wide band & it goes to over 20:1 A/F & MAF flow goes down (which occurs 1st?). By moving the throttle either way I can get out of it but if I keep it steady it will stay lean. TPS sweeeps cleanly .61 to 4.3 V and is fairly new as is the MAF. Other than this condition & idle (A/F changes) it runs pretty good. Under moderate & heavy accel its smoothe & steady. I've played with accel vs LV8 and almost all other parameters with no avail. Any similar experiances with MAF systems?? Thanks.

 

The MAF reading should never go down when opening the throttle....that just doesn't make sense. The sensor may be bad, or possibly just dirty. What brand of MAF is it?

 

Let me clarify, under slight to moderate accel it goes real lean & of course starts to stall, this is when MAF goes down & I believe it is just a result of the lean condition. I move the throttle & I can get out of the condition & all is well. MAF is stock Delco reman with only a couple of hours on it.

 

The ALDL updates are too slow to catch all the TPS/MAF failures. I'd suggest getting a spare one of each for diagnostic purposes.

4 36PPH injectors?. Are you running this on a V8?.

Have you been editing the MAF tables?.

 

Yes, 4 injectors in throttle body on a V8 350 El Camino....believe me I have a reason. Yes I have been adjusting the MAF tables to get the correct flows, on a chassis dyno & driving. It was doing this prior to adjusting. I will try to smooth transitions between tables. Before starting I noted that the voltage where each table ends is the same as where the next table begins and the Grams/Sec is sometimes higher & sometimes lower on the previous table. I would think this would confuse the computer if it lingers in this area.

 

Trying to run a wet manifold with a system designed for dry maybe more fun then you want.

Yes, each table has to begin where the last table ends, without a void. The table scalers, times, the entries should be equal.

ie if table one has a scaler of 12, and the last entry is 200, then the first entry of table two should be 2400, as an example, 24 with a table entry of 100, or a scaler of 48, and an entry of 50.