gpss97

ok heres the deal. about a week ago on the way to work my car started running like total crap. it was running way rich, to the point i could smell it in the car. when i came to a stop it was enough fuel to flood the engine and kill it, unless i kept my foot on the gas.

well i went to autozone and the only two codes that came up was tps low, and maf or map malfunction(p0100). well i changed the map sensor,and the maf sensor, along with plugs and wires due to being fouled out. well it runs alot better now, but i still have a rich condition, and still won't stay idling, unless i keep my foot on the gas.

oh i also changed the coolant temp sensor last night and no change. i didn't change the tps, because someone told me that wouldn't have anything to do with how much fuel it adds/takes. could this be an o2 sensor or the tps doing this? its getting really frustrating. i'm using like 40 bux in gas in like four days. and i did check and it is running rich being as it burns your eyes. fuel pressure is good, no exhaust leaks. i'm taking it to a performance shop today to get it scanned, but i just wanted to see if any of you guys have had an o2 cause this kind of problem. thanks
mike

ss.slp.ls1

You could test it by running your car with the o2's disconnected, keeping your car in open loop.

edit: For diagnosis of course.

Injuneer

Did the SES light go off when you changed the MAF sensor? Or is it still on? Why didn't you change or at least check the voltage on the TPS sensor? That determines, in part, when the PCM goes into power enrichment mode, richening the A/F ratio. And having the SES light on masks any other problems that may have occured.

P0100 is strictly for the MAF sensor, never for the MAP sensor in a 97. Check the pink wire in the MAF harness connector for +12V. There seems to be a frequent problem with that wire in the 97's.

gpss97

yeah thats what i was told but on the lil readout from autozone it said maf or map sensor malfunctioning, so i changed the cheapest one, and so on so forth. i'll check the tps tonight and see what its doing. oh and whoever had the car before me disconnected the light or something cause i don't get a check engine light.

Guest47904

Running rich can cause several issues. The most severe is souping. Washing the oil off of the cylinder walls causing premature ring and or cylinder wear. I highly suggest you stop driving it except to test it.

Running fat can and usually does kill O2s and catastrophic converters as well as plugs.

Remember when you get a code for a sensor, before you just replace it, do some measurements as Fred suggested. So check it as instructed.

Incidentally some things that can effect a DTC0100 are un-metered air from a vacuum leak, PCV valve or system problems, loose dipstick or unseated oil fill cap.

I just noticed you posted ANOTHER thread regarding reading voltages to the MAF. You want to be sure that you measured from the Black/white wire to the Pink wire going to the MAF. Using anything other than the black/white wire (which is the ground to the MAF) can give you the wrong reading.

If, for example you used the engine as the ground with one meter lead and simple put the other meter lead on the pink wire, you could read 12 volts. You could conclude there were 12 volts at the MAF. But if the ground wire going to the MAF were broken, there would NOT actually be 12 volts at the MAF. Understand?

gpss97

yeah thanks, i was actually doing it wrong. the maf does have 12 volts, thanks. well i think i found my problem. there is a fuse in the under hood fuse box. #10 don't know what it is, but it was blown and i replaced it and the car runs great now. i unplug the fuse and car dies won't run for crap. see when i got my car there are parts on the front end off a v6. ie the fan shroud thing that tells you the belt routing and plug gap, and the fuse box cover. the cover says fuse ten is an injector, and calls for a 7.5 and i called a buddy with a 96 ta, and his said 10 was a engine sensor fuse or something calling for a 20? so i don't know what that fuse is, but my car runs great now

oh yeah, the tps was bad, so i changed that last night as well. so it could have been the combination of that fuse and the tps. no telling. but thanks for the help guys.

Injuneer

The Owner's Manual has a page that tells you exactly which devices are on each fuse. The 97 manual shows that 10 is the "ENG SEN" fuse, and that handles the MAF sensor, the heaters for the O2 sensors, the skip shift (M6) and reverse lockout (M6) solenoids.