95 Aspire low power

[FB71]

I agree with except for the TPS, just because it starts and idles correctly, doesn't mean that the TPS doesn't have a dead spot near WOT.

[scitzz]

You said the code was Ignition Diagnostic monitor circuit failure ? I would look all my ignition components. I can't tell you how many times in the last month even that someone describing the same problem to me needed a simple tune up. This link gives you a simple process for checking the plug wires...

http://www.helium.com/tm/115529/there-variety-reasons-check

Can't hurt to check it out!

[gdawgs]

I had very similar symptoms once when I had a bad muffler. Ran great sometimes(usually when cold) then what I think was happening was the baffling moved around as it heated up and blocked the air flow out the exhaust. Once I replaced the muffler it ran perfectly again.

Not saying that's what the problem is with yours(especially with what you are describing about pinching off the fuel return line), but it wouldn't hurt to check that as well.

[larry220]

I agree with except for the TPS, just because it starts and idles correctly, doesn't mean that the TPS doesn't have a dead spot near WOT.

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Your right. hopefully today when I check the voltages on MAF and TPS I will get abetter idea whats not wrong. Thanks for advice.

[larry220]

Well its not the fuel pressure regulator.. I am thinking the injectors are not on long enough starving it of fuel on acceleration. The TPS voltages are correct and increase smoothly. But I did find the MAF appears to may be bad as the center pin on the 3 pin connector(MAF pin) is only (.3v) and does not increase with throttle increase. It is supposed to be 1-1.5v at idle and increase to 5v at full throttle. The supply pin is 12 v as it should be. MAFs are expensive I am going to try to clean it with contact cleaner and try it again. DO you guys think I am in the right area or could it be a bad o2 sensor or bad computer. I would think if the mAF has 12v to it and its never changing at the output pin it may be bad or the computer is pulling it down for some reason. I read where you can take the MAF off and put a power supply on the 12v pin and then blow air thru it and monitor the ouput pin with volt meter to see if it is working out of the car. Any advice.?? Thanks

[phantorn]

Try driving it without the Maf plugged in, the computer will substitute a value for the maf and it should accelerate normally tho not as well but it should not bog down

[FB71]

^^^ correct, called FMEM (Failure Mode Effects Management). I would not suspect the computer. It sounds like you have a bad MAF. Aren't there any junkyard units available near you?

[larry220]

Yes Ill call some local junkyards.Although I already tried a used part website but they didnt list any sensors.Maybe they cant guarranty them.
I did try unhooking the maf while car was running in garage and it still bogged down under acceleration. Maybe thats the FMEM mode your talking about. But it didnt seem any different than before when MAF was hooked up?? I only tried it for a few secs. Does the computer need to relearn the settings first by driving the car for that mode?

[scitzz]

My car will not run at all with the MAF detached!

[larry220]

Got a MAF coming today. I will try that and let you all know. I tried cleaning the old MAF but no help.

[larry220]

Wow it was the MAF. Now it runs good. The voltage on the center pin of the MAF connector is now correct and changes with RPM increase. I guess it was not allowing the injectors to turn on longer all along leading me to think it was a fuel problem. Thanks for all the help.