lejams

So the car died after leaving a friends house the other night and had it towed home. It barely restarts and when it does it idles rough, popping in the MAF, etc. if you touch the throttle at all, it stalls immediately.

Fuel pressure is normal, no major vacuum leaks from what I can tell, jumping the ICV and unplugging the TPS allows it to idle up to 1400 and a little smoother, but degrades after a minute or two back to rough.

The only thing that stands out, is whether the MAF is plugged in or not, nothing changes, and it should. In fact from what I can recall, it is behaving much like it would when I had unplugged it once a long time ago. Leads me to think this is the gremlin? I've check the obvious connections and the power supply, and it all appears okay.

How would I check the MAF further to see if this is the culprit. TIA!

fast951

Jim,

Check the MAF signal on DME #7. Your MAF is about 12 years old, so working from memory here, the voltages may be a bit different but the same principle.

At idle you should see somewhere around 0.5 - 0.7v. Voltage should increase with RPM and engine load.
Since you have a PiggyBack, you can monitor the voltages on Analog IN & OUT.
If it's the MAF signal, you'll have to trace the wiring path between DME and MAF.
Of course check the simple things first. 12V to MAF, Piggyback is programmed and functioning...

You could have a huge vacuum leak, where the engine is sucking un-measured air. The MAF signal will be there, but way off.

BTW the pop in the intake is an indication of a lean condition. So the theory of vacuum is very probable.

lejams

Thanks John, because in the past weeks there was some intermittent strange stalls, I'm more inclined to follow your suggestions tracing signals. Sent you an email.