Cant Rev Above 2300-3000 RPM

[PAFirefighter11]

Will not rev higher than 2300-3000 RPM or so... it's like it's hitting the rev limiter. Idea's?

'87 Conquest TSi.. video:
http://www.youtube.com/watch?v=JWi2tnMRTH0

Engine shot:

[Foolinaround]

This happened to my buddys crx,turns out his injector cracked.

[Preston]

MAF Sensor...it's a failsafe when it loses signal it won't rev past a certain amount to prevent leaning out due to ECU doesn't know how much air is coming in. And yes, it sounds like a rev limiter.

[PAFirefighter11]

Hmmm we were thinking it was the MAF sensor I was quoted $415 for a replacement when we did a quick Google search with my buddies iPhone..

[Preston]

Test it first, make sure it's plugged in, I dk how many wires you have on yours, but no matter how many, one will be a 5v reference, one will be a signal (0v to 5v) about .4v at idle, and one will be a ground. Make sure those are all acceptable, try cleaning the MAF, you can use brake cleaner if you don't have throttle or MAF cleaner, just let it dry for a few minutes before you put it back in action.

[PAFirefighter11]

Okay, so here is the latest...

When COLD, and I mean cold.. aka first time I come out to start the car after a day or more, it runs great. This happens for approx 3-4 minutes then it either dies or I shut it off. Then when started again, same revving issue where it won't let me above 2000-3000 RPM.

Throttle cable has good slack.

TPS is good.

Timing is good, approx .5* retarded.

Plenty of fuel is going into the throttle body at idle, but it looks as though nothing is coming in from the 2nd injector when on the gas. It was hard to see, as it backfired in my face lol.

Spark Plugs are still okay.

MAF test results... while car is idling

Yellow w/ black wire = 5v
Red = 10.9v
Green w/ red = 5.9v
Black w/ yellow = 0v
Black w/ white = 8.2v
Green w/ red = 4.7v

Vacuum lines are good. I replaced any that looked so-so. Routings are all good. Tell me if this is normal: At idle, of the 3 nipples coming off the throttle body, only the 1 closest to the firewall side has good vacuum. The other two have barely anything, if that. I thought the nipples may have been clogged, so I checked. The two end ones are the same depth, the middle one is maybe 1/2" less in depth.

I talked to my buddy who is a Chrysler tech via the phone. He said it sounds like a bad ECU/PCM, whatever you want to call it. He is going to come over on Saturday with a SnapOn Scan Tool from work, as well as some other tools and such to check the electronics. Are these cars OBD 1? The connector in the top portion of the glove box looks like it to me, I just wanted to confirm. Would bad ground/power to the ECU/PCM cause this type of issue?

[wrx-auto-x]

i know a guy that currently owns 6 of these cars, most are for parts cuz they always break and are expensive to fix, good luck with repairs.

[russiankid]

Originally Posted by Preston

Test it first, make sure it's plugged in, I dk how many wires you have on yours, but no matter how many, one will be a 5v reference, one will be a signal (0v to 5v) about .4v at idle, and one will be a ground. Make sure those are all acceptable, try cleaning the MAF, you can use brake cleaner if you don't have throttle or MAF cleaner, just let it dry for a few minutes before you put it back in action.

Brake cleaner can damage a MAF sensor. There is a reason why they sell MAF cleaner.