'85 redline problems....

[ac604605]

Hey,
I own an 85 that spun a bearing recently and just had a rebuilt engine installed. The engine runs great except for an issue with the redline and idle. I don't know if they are related, but the idle is rough, smells rich and sets at about 1,500 RPM. The car will run up to about 7,500 RPM if you simply rev it in neutral, however when you are accelerating in any gear it gets to 6,000 RPM and stops. It doesn't bump like a rev limiter would, nor does it slow down; even if you keep your foot in it, it holds steady at 6,000. Any suggestions or comments would be great.

[1fastmr2]

Check your Air Flow Meter flap.

[mr2tim]

Check Pg Fl-16 BGB
Check a/c idle up circuits?
Any Dianostic codes flashing?
Throttle position sensor?
Fuel pressure?

So many questions, so little time...

[ac604605]

Thanks, air flow meter looks good. As for the other things, I will need some time to check... I'll post results when I'm finished.

[PETC]

You are running super rich, pull the plugs, I bet they're carbon fouled. Something is wrong with your fuel delivery system, and since it's not carbed, the only thing that would up the output of the injectors is the AFM, or I guess the FPR could be doing it as well.

Check out your fuel system, and make sure you're getting proper voltages/resistances in your ignition system.

I love that answer, it's like the answer to everything.

[ac604605]

Thanks for all the help. I only pulled two plugs, but both of them had carbon residue on them. If it makes a difference, the car was in the garage for almost a year without being driven; for the first couple of weeks I drove it the battery and air filter were in rough shape. I have replaced both of them but I haven't yet seen any improvement. As for pressure and diagnostic, I will hopefully know by Tuesday. My father is a tech at a local dealership, if it comes down to it I'll just ask him for help, but I want to try and fix this one out on my own. Once again thanks for all the help.

[Dacia]

This one happened to me, two injectors froze shut while I had the engine rebuilded and I could not get the idle below 1000.Unplug your injectors one by one too see if they working.

[ac604605]

Fuel filter was horrible, so I replaced it and that helped somewhat. Adjusted the idle screws and spring gear inside the MAF; idle is better than it was, around 1000 RPM. The car still only gets up to about 6000 RPM before cutting back. Fuel pressure and throttle position all looked good. Didn't have time to diagnostic, not sure what the ac idle up circuit is? Like I said before, the engine itself is new, but if it makes a difference everything else is still the same; including the TVIS. I don't know a lot about engines but is it possible for the converter to get clogged and cause something like this? I talked to my father about the problems, he was surprised that after the new filter the problem wasn't affected. He told me that the newer on board computers will learn the characteristics of how the car uses fuel and may have to "re-learn" all the adjustments we made, however he didn't know if such an old MR2 would do this. Finally, if you accelerate at about 1/4 throttle the engine will pass the 6000RPM mark and red line. In a couple of weeks I'm driving from Austin to New York for college. I'm not worried about the car making the trip, but I am worried this may be a precursor to another more serious issue down the road. Any tips or thoughts are greatly appreciated. Thanks for all the help!

[ac604605]

Oh one more thing, I thought the plugs looked like they had carbon on them but when I showed them to someone else, they said they looked about as good as spark plugs could get.

[ac604605]

Any new thoughts on this?