HELP!!!! Engine revs uncontrollably.... can't idle....

spencersummerfield · Post by **spencersummerfield** » Fri Mar 06, 2009 7:30 pm

Well I got the my mag intake all set in, and wired it up. BUT I used the WOT signal switch and wired it to my TPS the middle pin.

ANd I think I fried a bunch of stuff.

I connected my WOT (white wire) to the orange wire on my TPS and the car revs insanely.

* This diagram shows WOT connected to "TPS Signal" WAS THIS NOT CORRECT?

SO I unhooked EVRY wire that has to do with the MTV wiring and it still does it.

When I turn on the car it revs to 2500 going Vroom vroom vrom, then after about 10 seconds of this it takes off right up to 8000RPM!!!!!!!!!

and will stay there for a sec then drop down to 2500, then RACE off again to 8000 RPM...

I tried 3 PCM's and tried unplugging the TPS and IAC and manualls setting idle. Still nothing.

Now my engine chugs and sounds like it is back firing.

I Hope the problem is that the TPS and IAC are TOAST.

Can someone tell me how to test a TPS Sensor???
Can I use a OHM meter??

I checked the connector at the Throttle body, Turned the ignition on and The pins showed. 1 ) Gound 2) 5V - Signal wire 3) 5V - Voltage wire.

So it seems the wiring is ok...

The IAC I pulled it out and the Pintle thing or probe is frozen, Should I be able to push the IAC probe in and out????? Cause it is Frozen in place.....

I am so frustrated I spent all day getting the Intake in and modifying brackets and shit and it only led me to no where...

Also The mag intake came witha different MAP SENSOR.... I took it out and put mine in. Would this cause any problems?

and can you test a MAP Sensor using OHM's?????

I am begging for help here!!!!

esteinmaier · Post by **esteinmaier** » Fri Mar 06, 2009 7:55 pm

It's not electrical. There's a mechanical problem allowing air to get into the manifold. You probably forgot to put the bellows tube on or something.

spencersummerfield · Post by **spencersummerfield** » Fri Mar 06, 2009 8:54 pm

esteinmaier wrote:It's not electrical. There's a mechanical problem allowing air to get into the manifold. You probably forgot to put the bellows tube on or something.

forgot the bellows tube..... NOPE

Donkeypuncher · Post by **Donkeypuncher** » Fri Mar 06, 2009 9:09 pm

I'd say it's the IAC, mine did something very similar not too long ago. It would idle like you described, but I turned it off before it could rev up too much.

Mine only did it for a short 2 mile drive, then everything was fine when I started it up again. I think a small shaving of plastic found it's way into the IAC causing it to stick for a short time, I had just drilled on the air box minutes before.

INVUJerry · Post by **INVUJerry** » Fri Mar 06, 2009 9:11 pm

There is an air leak somewhere. TPS voltage should read .0XX volts closed, and 4.6 WOT. If you unhooked all the MTV shit and it's still doing it, it's a vacuum leak somewhere. My 98 did this when I left an EGR port open, but you don't have EGR. Make sure the gasket in the middle portion of the intake mani is fine, that you didn't rip the intake mani gasket at the head, and that the seal around the actuator is still there.

Post by **occasional demons** » Fri Mar 06, 2009 9:37 pm

Are you still using the 2000 IAC? If so you won't be able to move it by hand. It needs positve or negative polarity pulses to move the pintle in/out. These pulses are very rapid, as it moves 1/4 turn at a time. IDK how you would even test it, other than an oscilliscope to see if it was getting a signal.

If you are not using a '00 pcm/IAC:
The IAC at rest should be seated. If it is off the seat, then that is part of the problem. I know 4500 rpm is achievable through the IAC, but IDK about redline. It is basically a soleniod. The more volts the more it opens. It uses the 0 to 5 volts also.

But I would check for any loose hoses, gakets like already mentioned. Even if the TPS voltage was at 5 volts in any position, it won't rev that high without air comming in.

spencersummerfield · Post by **spencersummerfield** » Fri Mar 06, 2009 9:54 pm

Thanks for all the suggestions ,

TPS voltage reads 5 volts when closed or open....
This could be a problem.....

Post by **occasional demons** » Fri Mar 06, 2009 10:06 pm

Have you checked the TPS with an ohm meter to see if it varies? IDK off hand what it reads, but I could check tomorrow. Point being, if it does change value, then there may be a short somehow in the wiring letting the 5 volts go through. If it stays constant then the TPS is fried.
Edit: You would need to test the pins on the sesor it's self with it disconnected. (Incase you didn't know.) connecting it to the wires would give a false reading, and voltage may wack the ohm part of the meter.

I wouldn't want to cause you any more grief!

esteinmaier · Post by **esteinmaier** » Fri Mar 06, 2009 10:11 pm

The IAC itself just doesn't pass enough air to rev all the way up. Maybe 3k at most, but not bounce off the rev limiter. Find where the air is coming from, and I would be willing to bet the rest becomes much easier to diagnose.

Donkeypuncher · Post by **Donkeypuncher** » Fri Mar 06, 2009 11:36 pm

Now that I think about it, mine didn't pass 4k rpms off the throttle.

But if it was an air leak wouldn't it just rev up right away to redline? The fact that it is trying to idle and blipping the throttle makes me think it's the IAC.

This is a tough one to figure out, I'll have to read the fsm and think about it.

quicksilvr · Post by **quicksilvr** » Sat Mar 07, 2009 2:09 am

Quite a bit of good advice has already been, given so I will echo a little of it. Because the car does not have a "drive by wire" electronic throttle, something physically has to open the throttle plate. Whether that is the accelerator cable or your finger or whatever. Redline flavored rpms are WAY to high for a small vacuum leak....obviously to get to 7500 rpm the right way, the throttle is all the way open.....that's a big hole.

Is the throttle plate properly screwed to the pivot bar in the TB? Is one of the bungs on the intake manifold not plugged? Is one of your fuel injectors not seated?

I know you feel like you've checked everything...I'm just throwing stuff out there..

Donkeypuncher · Post by **Donkeypuncher** » Sat Mar 07, 2009 2:30 am

Was the car running normal with the magnum manifold before you tried to wire up the WOT switch? That might narrow it down to 1 thing being the culprit.

gilly02le · Post by **gilly02le** » Sat Mar 07, 2009 5:30 am

check the brake booster fitting on the back of the
Intake manifold.... when i installed mine, i forget to hook it back up at first. Started it up and it revved right to the limiter until i could turn it off.. I also had a vacuum leak because i didn't lube up my o-rings before pushing the injectors back in, causing a rough idle.

spencersummerfield · Post by **spencersummerfield** » Sat Mar 07, 2009 7:36 am

Alright, again thanks for all the advise, I found a could broblems Last night so I am hopefull I can remedy it today .

Findings:

IAC- fried, checked with 5 volts

Intake manifold not seating proprlg due to original plastic intake mounting bracket.

Torn intake manifold gasket

Tps/ xes WOT switch ARE wired correctly.

No engine codes

Picking up new IAC, removing what left of the intake bracket, replacing gasket and should be good to go.

Will post back

esteinmaier · Post by **esteinmaier** » Sat Mar 07, 2009 9:00 am

The IM gasket was the major culprit here. I'm sure your wiring did fry the IAC, but that's only a small part of the drivability problem. You're using a WOT switch to control the butterflies, right?

But at least you have a starting place.

spencersummerfield · Post by **spencersummerfield** » Sat Mar 07, 2009 3:22 pm

Its ALIVE!

She runs , the IM Gasket was defiantly the problem and I also replaced the TPS ,TPS Harness, and IAC.

She still idles ought but thats beacause i am using a AFX for a AUTO....
I have to go to the stealership to get them to program my SKIM CODE into my new AFX R -MT

Also my O2 is throwing code P0132 so I am goinh ot have to replace that also.

But other than that it runs ok.

I do NOT have the MTV hooked up because I am not convinced that the WOT is hooked up properly.