[Spectre66]

Alright guys, I'm hoping someone out there has come across this problem before. I have a '99 Wrangler and I just replaced my exaust header with a Banks exhaust header. I was really careful when removing all of the wires, marking each one before I removed it. I got everything back together and double checked all of the connections but I have a problem.

Now when I start the engine it goes to Wide open throttle, and I have to kill it. I've double checked everything, even triple checked... What am I missing?

[frontmounted]

Is the throttle body actually stuck open or is it like an electrical TPS problem?

[Spectre66]

The throttle body appears to stay closed, its definatly not stuck open. I thought it might be a faulty idle air controller but I don't know why that would fail like this. Any other ideas?

[Spectre66]

Its getting late and I'm just going to have to start back on it tomorrow. I didn't realize I didn't say this earlier... this is a 4.0L engine, stock other than a modified airbox for a snorkel and now a Banks Exhaust header.

As far as I can tell the throttle is operating fine, it fully closes without a problem. A buddy of mine was helping me earlier and he said he didn't think the throttle was opening up(as best he could see) at startup. But regardless, I have to kill the engine right after it starts because it seems like it would redline if I didn't.

Thanks again.

[Jerry Bransford]

It's caused by a leak between the header and head, so long as another vacuum hose connection on the head itself isn't leaking. Something isn't right where it's bolted up to the head.

[Spectre66]

Yeah, I thought about that too... we looked all over, thinking that maybe there was a leak, tightened down some bolts, no effect at all on the problem. If we rule everything else out I guess I'll have to pull the manifold and header off again, I'm just not looking forward to that....

Anyone have any better suggestions?

[Spectre66]

Jerry,

That's what it was. I removed the intake manifold and took a close look at it. Apparently I was off the alignment pin, I could see an indentation where the alignment pin was touching. Put it back together and what do you know.... It runs...

For anyone who has this problem or is thinking about doing the exhaust header for the first time: Put the exhaust header on first attaching it to the head with the 3 bolts that are not shared by the intake. When you put the intake back on, put it up to the head and let the alignment pins hold the manifold while you put all of the bottom bolts in. While you are bolting make sure to feel around the intake and the alignment pins to make sure you don't feel any gap what-so-ever. Once the bottom bolts are done, do the top bolts. Torque the bottom bolts, inside out followed by the top bolts inside out.

Hope this helps someone in the future.

Keywords(for later searching): High RPM Intake Manifold Exaust Header

Again, Thanks for everyone's help!

[urbanassault]

FYI you can spray some b12 at and around the suspect leak areas. Quick locator.

[RoKnAzn]

Great job....