2.3L ('83-'97) 1996 B2300 Bipolar MAF

[Suzonda]

1996 Mazda B2300 2wd 5spd, 4PIN MAF.

So over the past week I've noticed my lack of power has turned into NO power. (I can't even get above 64mph on highway in 4th, 5th isn't even an option). So I plugged in my Foxwell scan tool, it came up with a P0172 code, cleared it, then truck backfired to a stall. It took 4 tries to start it back up and it pinged and popped for about 45sec until it got to normal idle. The code came back, cleared it again, and this time it just died. I started it back up then I went into live Data and the MAF was reading a 7.34lb, I brapped the throttle, then it dropped down to .001-.000. I know that it should read anywhere between 2.3-2.7. I cleared out the code, then the MAF reading went all over the place. (Jumped between the values of .000-4.56lb) I have another PCM from a 1995 B2300 5spd 4x4 OBDII 4PIN MAF but I'm not sure if would work on this one since the gauge cluster didn't (Not related but it has different wiring apparently). THERE ARE NO VACUUM, SEAL, OR GASKET LEAKS. ALL EXHAUST FROM MANIFOLD BACK IS BRAND NEW FROM FORD. Does anyone have ANY ideas?

New parts Include ECT, IAT, IAC, TPS, Cam and Crank position sensors. I also replaced the entire fuel system. Brand new Delphi sending unit, new fuel filter, new factory lines, FPR, and Motorcraft Injectors. I tested the injector wiring, the timing is 10-15 BTDC at idle, 28-35 @2500-3200rpm.

 

[Dirtman]

Why do people think clearing codes is at all helpful? You just erased the freeze frame data that would have been useful in determining why the code was there in the first place...

What is your fuel pressure?

What are your fuel trims?

Do the fuel trims rise or fall drastically under engine load?

Is the fuel pump a motorcraft?

MAF sensors should be read in Grams per second not pounds so dunno what those numbers are?

You said the FPR is new but new doesn't always mean good, if you pull the vacuum line off can you smell any fuel in it?

 

[Suzonda]

The sending unit and pump are Delphi (As stated above) The fuel trims were not read by my scanner or the Innova scanner that OReilly has. (2 dashes = No signal = Severe malfunction in OBDII circuit or PCM) Fuel pressure is right around 40psi. The old pump only pushed about 28-30psi (Hence the replacement). The FPR has no leaks, no raw fuel smell. I also replaced the PCV valve and hose, which helped a smidgen but not enough. I also took this morning to replace the MAF with a Motorcraft one, cleaned throttle body, intake, and redid the gaskets for valve cover and both intake mating surfaces. Since then it doesn't cutnoff and wheeze when I try to brap the throttle but all readings are still the same. No DTCs were shown but it didn't show anything when it had a shattered o2 sensor a few weeks ago. Something tells me my PCM is just straight up f***ed.

 

[scotts90ranger]

High MAF reading doesn't necessarily mean the MAF is reading wrong, it can mean the engine is running bad and needs more air to run... If you looked at the IAC duty cycle at idle it would likely be reading much higher than normal...

What does the computer think the coolant temperature is compared to ambient temp on a cold start?

Throwing parts at things isn't normally the answer, there's likely something else going on. Have you done a compression test or leakdown test? Does the top end rattle like a valve spring is broken? There's all sorts of possibilities. I understand your frustration and wish there were more concise answers to your problems. It could be that your ECM is screwed up, could mean the cam sensor is mad too...

 

[Suzonda]

Found the problem. It had an aftermarket MAF on it (Plus my OBDII scanner was really screwy) and it wasn't reading properly. Replaced the MAF with a factory one, it did the same thing. So I pulled the loom off and chased wires, come to find out the insulation down by the head was melted and was causing all sorts of problems. replaced the wiring, and now she runs fine. this is why I hate aftermarket crap.