mortymower

Okay so im looking at buying an 87 951 and it has an autothoority maf but generiric plumbing so the filter is smushed by the headlight bracket. But my main question is the car runs well when you give it gas and its fast, but when idling sometimes it is okay, but most of the time it is stumbling all over the place and it dies every once in a while. Black soot is pouring out when it does this. The MAF plugs into the AFM plug with a getto little converter which has an adjustment screw in it (is this correct)?

My main quesiton is is all this stunbling because of MAF, and I have heard autothority is good so do i need a new controller, or should i sell it and buy a lindsey or vitesse and not worry. Its an 11 hour drive home so i want to make sure i can fix it when i get home without a ton of cash. thanks!

fast951

The APE MAF is not a bad unit. However, the problems you describe are not MAF related. Either a bad vacuum leak or the car is running richer than the chips were designed for.
It might be a simple fix!
- For starter, rotate the MAF while the car is idling, you will hit a sweet spot.
- Then use the "****" in the MAF harness, try to lean the mixture a bit. If it doesn
t do it, richen it.
- Set idle by adjusting the idle screw.
- Disconnect O2 sensor, notice any difference?
- Check FPR and vacuum line going to FPR.
- Pressure test the intake to find leaks (if you have the time, I'll do this first).

I would fix it before driving it 11hrs.

mortymower

when you say rotate the maf, what do you mean, there is only three wires coming out and they plug into the AFM harness and there is a little screw on one of them?

rberry951

He's referring to the clocking of the MAF in relation to the pipe, rotating it on its axis. This changes the signal and hence is a bit of a tuning tool on MAF cars.

951Tom

Loosen the hose clamps and rotate the MAF in the hoses, then retighten clamps.

Tom
'87 951

mortymower

wow did not know that! thanks I will try that