Redline while idling

[yousmellfunny2]

Yeah you read that right.

If the car sits for a day or two, I will start it up and it will idle just fine.

Its not until I take it out of the garage or put any load on it, that it just gets crazy.

Once going, the car will shift a couple of gears fine, and then it will start to rev when I change gears. First it will try to rev to 2.5k-3k. After driving a little more, if it put it in neutral is thinks its full tilt, and will rev to 7k.

I have to drive with my foot on the brake. I have not been driving anywhere except around my local subdivision.

Once I park the car and turn it off. As soon as I turn it on, it tries to rev full tilt again.

The car threw a 1216 code for the TPS.

I bought a new one and installed it. Still same issue. Same code displays 'some' of the time.
I took out and cleaned the ICV.
I checked the MAF (it's off a 540i, car is a 95 s52 ODB1 swap) and MAF is fine. Car won't start when MAF is not plugged in.
Checked and replaced a cracked hose.
Checked wires to TPS and seems to be getting correct voltage.
No floor mats :)


Read about throttle cables, I took off the cruise control cable, and made sure nothing was hanging up while it was opening. And it still does it.

The crazy part about this, is the throttle body isn't open when its running to 7k.

I can make a video if need be, but this has gotten crazy. Any ideas what it could be?

[jakermac]

Its gotta be a big vacuum leak.

[TArsen]

That's pretty crazy..

If it's an i take leak thats making it rev that high that also means that there is more fuel coming in or else it would just stall... Are you 100% it's not the cables?

Sent from my iToaster

[Lints]

The crazy part about this, is the throttle body isn't open when its running to 7k.


First, how did you verify that the plate isn't opening when its revving?

Second, if the plate is indeed not opening, the air must be coming from somewhere. Some kind of major vacuum leak like Jakermac said. It must be after the TB, which narrows things down. It must be some kind of leak on the intake manifold. The strange thing to me is, even if the air is getting in, thats only half of the equation, wheres the fuel coming from? Something must be telling the fuel rails to inject more fuel. Isnt there a vaccum hose that runs from the intake mani to the fuel rail? I wonder if thats gone missing or accidentally got cut or something.

[yousmellfunny2]

I figured it was a vac leak. But chasing it down is going to be painful.

I THINK that the tb blade isn't open because when it is reving like that the outside mechanism that opens it, isn't moving.

Can the blade open without the spring being pulled?

[Randy Forbes]

I figured it was a vac leak. But chasing it down is going to be painful.

I THINK that the tb blade isn't open because when it is reving like that the outside mechanism that opens it, isn't moving.

Can the blade open without the spring being pulled?Are all the return (to idle) springs intact on the throttle body? I've never heard of any failing, but clearly something's going on, and troubleshooting is the process of elimination...

[rajicase]

^^I'm not really gonna be too much help but someone correct me if im wrong. I could see a vacuum leak being an issue here, but how would it be getting the fuel to rev to 7k? Could the TPS still be bad? I know you said you replaced it, but unless it was still bad and reading wide open throttle? Or possibly the vacuum hose that runs from the fuel rail to intake manifold could have come off/cracked/whatever? I know I am not much help here, but I know when I removed my intake manifold that vacuum hose was in really sad shape(the one that runs from the fuel rail-manifold).

[yousmellfunny2]

So after looking some this morning I noticed that the blade cannot open on its own without the springs. I cleaned all the springs and they all close and open just fine. And return to close.

So that being said. It could be a huge vac leak after the throttle body or tps/wiring might be bad. I still find it odd that it is sending that much fuel for it.

I'm on a phone now so searching for a vac diagram sucks. Anyone have any links or diagrams of the vac lines and locations?

Thanks again for the responses.

[bucs19]

Mine did this and it was the cruise control module thingy. Unplug the fuse and try again..

[ThreeD]

You could also disconnect the icv intake hose and plug the regular intake that it fits into, and then when it starts revving plug the icv intake with your hand to see if it stops. Would help to isolate the problem

Post above me is worth looking into tok

[yousmellfunny2]

I pulled the fuse for cruise control and the car wouldn't start.

I will try to take the plug out of the module and see if it will start then

[jdantuono]

Mine did this when the throttle body arm was getting caught on my boot.... But I think the cruise control is certainly a good place to start.

...or maybe this is your car's way of saying drive me like I'm meant to be driven? 7k all day.

[yousmellfunny2]

Fixed it... kinda

After going through everything, I found a cracked hose, and a bad cruise control cable.

What I think was going on, was the cruise control cable came out of the housing a little, and when the car wasn't running, it would slip back in and not have any tension on it. When I would start the car, and give it a little gas, the cable would pop out on release, and pull the throttle up a little. I can't imagine that, with a cracked hose, would make it rev so high. After taking the whole throttle body out and removing the entire cruise control module/cable (don't need it, never used it), I readjusted the throttle cable and reset the idle screw, it wasn't reving like crazy. I also fixed the cracked hose.

Now it is just the opposite. I was idling around 4-500 rpms, and it was dying. I adjusted the idle screw and its around 900-1000 rpm at idle. But it is bouncing. Not sure what else, I checked all the hoses, I believe there are no vac leaks. I have not reset the error codes yet, but I will and see if anything pops up.

Any suggestions on the idle jumping around?

[Lints]

I think 900-1000 rpm might be too high for an idle. I think its supposed to be closer to 750.


Lower it a bit and see what happens. If the bouncing doesn't go away it is probably a dirty icv or another vacuum leak.