Author Topic: Redline 5500 rpm??? (Read 4145 times)

Jorgeconrico · « **on:** May 22, 2009, 10:01:51 AM »

The engine seems to run perfectly up until 5500 rpm, and then feels like I'm at the redline and will not rev any higher. Not sure how high these motors can rev but I'm pretty sure they can go beyond 5500. Fuel filter, vac leak, plugs...??

DesktopDave · « **Reply #1 on:** May 22, 2009, 10:31:44 AM »

That's an odd one. Our redline is 6500, unless you've been chipped. I just verified it yesterday

Maybe test the cam position sensor or the MAF/AFM?

Do you have any other issues that might contribute? High-speed misfires or idle problems? A vacuum leak or bad MAF might lean out the engine far enough that it'd misfire at high RPMs. Could also be that your timing is off somewhere, but I'd check that last because you have to pull off so much stuff for that.

The DME won't fire the coil packs if it thinks you're over-revving. It uses the cam position sensor for that reading, IIRC. Clean & test for proper resistance?

One more thing I thought of - on my car there is an extension for the MAF/AFM. I was looking at your blog (nice car, BTW) and I remembered something...it's like the wiring harness was too short, so they added an 'extender.' Same round conenctor, just male on one end and female on the other. The connectors didn't mate exactly, so that extension connector was full of water.

I re-routed the harness so that the extension wasn't needed - I plugged it into the MAF/AFM. After that and a good cleaning of the crank position sensor, the car started right up. Maybe have a look-see?

Jorgeconrico · « **Reply #2 on:** May 22, 2009, 10:42:31 AM »

No high-speed misfires and it idles very smoothly. So i dunno. Pulls throughout the rpm range until it seems to redline at around 5500 rpm. The car runs perfectly except for this.

DesktopDave · « **Reply #3 on:** May 22, 2009, 09:33:53 PM »

That's really odd, I agree...but better to leave it running with one quirk...if it ain't broke...don't fix it.

Pitch-Black · « **Reply #4 on:** May 23, 2009, 02:22:53 AM »

Quote from: DesktopDave;72286

That's really odd, I agree...but better to leave it running with one quirk...if it ain't broke...don't fix it.

You mean fix it till it breaks right...:p

You could also disconnect your exhuast before the cat and then rev it.

If it goes over 5500rpm there's someting wrong(a restriction) with your exhuast.

Jorgeconrico · « **Reply #5 on:** May 23, 2009, 07:20:16 AM »

I believe i found the problem. Its a vac hose. The hose was cracked so i started to dig around. I decided to take the intake manifold off and take care of all that mess under the intake. Ripping things apart is fun, but putting them back not so much. Hopefully i can pull this off......LOL. By the way this hose was coming loose so i pushed it back in and the problem was gone, but as i drove the hose came loose and the problem was back. So i decided to get crazy and get rid of that mess. Hopefully i can re-route the vac/coolant lines without a problem. Ive checked out a thread that one of the members had and he did a good write up with pics. This should be a good weekend.......I can post pics but im sure you guys have seen this procedure a million times.

DesktopDave · « **Reply #6 on:** May 23, 2009, 07:30:43 AM »

I'm heading there just as soon as I buy some gaskets. Let me know if you have luck re-using the old gaskets, or if you got a good price on them somewhere.

Good luck fixing whatever lurks under there!

Jorgeconrico · « **Reply #7 on:** May 23, 2009, 07:36:34 AM »

I'm going to get some new manifold gaskets....I've come this far. BTW what lurks under there is evil.

Jorgeconrico · « **Reply #8 on:** May 28, 2009, 05:50:15 PM »

Ok so i pulled out the maze of hoses under the intake and replaced them with the 3 hose setup and i take it out for a spin and it drives excellent. I then decide to take it out again and it began to redline at 5500 again. This only seems to happen when the car is warmed up. Like i said the car idles perfectly and pulls strong up until this point. Thought it was a vac leak but i guess not. Please help.

romkasponka · « **Reply #9 on:** May 31, 2009, 03:09:34 AM »

Quote from: Jorgeconrico;72542

Ok so i pulled out the maze of hoses under the intake and replaced them with the 3 hose setup and i take it out for a spin and it drives excellent. I then decide to take it out again and it began to redline at 5500 again. This only seems to happen when the car is warmed up. Like i said the car idles perfectly and pulls strong up until this point. Thought it was a vac leak but i guess not. Please help.

Check your EGOxygen sensor....

Jorgeconrico · « **Reply #10 on:** May 31, 2009, 09:05:49 AM »

I'll check my "EGOxygen sensor".....thanks