Symptoms:

-Consult shows maf at 0.86V with engine off key on, 0.86-0.89 with engine unning. s/b ~1.5 with engine running according to FSM
-Rough idle, misfiring, idles 1000-1500 RPM
-MAF sensor code (12)
-Pinging
-Appears to be running in safe mode
-Brand new NGK iridiums when first started, now sooty black

The symptoms seem to suggest:
-Bad MAF/turblence at MAF
-Vacuum leak

Any thing else it might possibly be?


Things I've tried, with no luck:
-Swapped MAF's, unsure if either was good to begin with
-Bought some CRC MAF spray, cleaned both
-Regrounded center MAF wire to intake manifold, reading 0.000V
-Verified MAF was getting battery voltage... 12.2V with engine off
-Bench tested MAFs with key on engine off by gently blowing at them from ~1.5ft away gave a reading of 1.0-1.2V
-Swaped out ebay WAI for stock intake (thinking ebay intake could be creating turblence)
-With engine idling and filter off I put my hand over MAF, could feel air going through fingers, engine died when I covered it competely.
-Removed intake manifold, swapped every thing over to second manifold, checked hoses for cracks,installed new pcv hose, all new vac lines, cleaned tb, re-blocked off egr ports
-Verified timing is at 15
-TPS is at .52V closed
-Hooked up vacuum gauge, vac is around 20-22in Hg when idling, except when it pings, it drops momentarily to 15 in Hg
-Sprayed starter fluid around, couldn't find anything
-Swapped ecu's
-Pinched off brake booster hose, no change
-Pinched pcv hose hose, no change
-Disconnected exhaust at collector


Next thoughts
-Try a third maf, or find someone local to verify if either of my MAF's are functioning
-Start blocking off any unneeded items, canister purge system, pcv line, brake booster, FPR line vac reference line.
-New intake manifold gasket
-Try propane to find vac leak

Anything else to try?


Also does anyone know if when running in safe mode does the ECU ignore the knock sensor?

forget the propane and started fluid and all that jazz...it very rarely works I don't care what people say. Hook your compressor up to your CAI and pressurize your intake up to about 20psi, then step back and listen, you'll find your leak very quickly.

As far as running really rich and all you need to let us know what your set up is. What motor, maf, ecu, etc etc.

On my maf I have around 0.45v with key on and 1.54 idling this seems to be typical with most mafs. 0.8 seems awful high to me I'm wondering if you don't have either the wrong maf for your set up or have it wired backwards.

I forgot about an Avenir MAF I had bought for a future turbo conversion.

With the Avenir MAF voltages were .51V key on engine off and 1.3V at idle which is consistent with the FSM specs on the DET.

Doing the same bench test as I did with the other two I could easily get the Avenir MAF above 2V blowing on it from 1.5-2ft away versus only 1.2ish with my other two. Looks like I bought a couple of bad MAFs that failed in the same way.

At least I can use one of the MAFs for a core charge when I go to pick up a new one.

That is a good tip about using the air compressor, I'll be sure to do that next time. I resorted to blowing on my pcv hose while at the same time fondling my intake manifold feeling for leaks....


The car is a NX2000 with intake and headers, purchased in a non-running condition. Was told engine was freshly rebuilt and it looks it since the plugs were brand new and the block was spotless. From what I can tell it is a B14 block with a highport manifold.