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Discussion Starter #1
on my 2000 tj i have just installed a banks header and now it revs to 4 to 5 grand and i shut it off

what could be causing this?

vacum leak?
trottle positioning sensor?

any ideas would be helpfull

Thanks in advance
 

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is it throwing any codes? It sounds like it could be the TPS, however I think it would throw a code right away if that was the problem. If you haveaccess to any of the "good" diagnostic equipment, it shows real time numbers for O2 sensors ect, that may help narrow the problem, not sure if it can read anything from the TPS tho. Good luck.
 

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on my 2000 tj i have just installed a banks header and now it revs to 4 to 5 grand and i shut it off

what could be causing this?

vacum leak?
trottle positioning sensor?

any ideas would be helpfull

Thanks in advance
You screwed up reinstalling the intake and have a vacuum leak. Take it apart and fix it.
 

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You screwed up reinstalling the intake and have a vacuum leak. Take it apart and fix it.

he said header not intake. headers wont cause vacum leaks.

check your codes and make sure you dont have a tps or iac code.
might want to reset your computer also.. you changed its parimeters and it might be freaking out.
 

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he said header not intake. headers wont cause vacum leaks.
BUT, did the original poster say he didn't loosen the intake or remove any of the intake bolts when doing the header install? Because we don't have that info, Blaine's suggestion could very well be the problem. Maybe not, maybe nothing on the intake was touched, but we don't have enough info to rule that out.

Grand663...did you mess with the intake at all? Possibly remove any vacuum hoses during the install and crack a fitting or not replace a line? Possibly, you bumped something vacuum related while removing the old manifold, installing the new header??? Vacuum leak on intake is a simple troubleshoot, is a common cause of revving, and I would start there. TPS is next in line for sure...would be nice if you even had a cheapo code reader...Harbor Frieght usually sells them for under $30, many auto parts stores loan them out for parking lot diagnosis.
 

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Discussion Starter #6
yes i did remove the intake

the way the banks header is set up you have to remove everything on that side of the motor to get it on

i think im going to go get another gasket and see what happens

Thanks for the help everywon
 

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An easy way to check for vacuum leak is to get a can of starter fluid, start the jeep and then start spraying all around on the intake. If your problem is a vacuum leak then the engine should rev when you spray starter fluid on the leak. Although I'm not sure how well it will work with the engine already rev'ed up to 4k.

Also might check the IAC motor (I think OBDII had these). When I replaced mine on an OBDI system the engine reved really high when first starting but the computer just had to calibrate it. Took about 1-2 mins and the idle slowly came down. Not sure how long you have let it run but it just might need to recalibrate something.

Also you can check the TPS w/ a mulitmeter and the engine off, key on. I don't remember the exact readings. Google it and you should find the answer pretty fast or try cjoffroad.com, it will be on there for sure.
 

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had the exact same thing happen when i did mine, u can't just throw the header and intake back on, it has to line up with the ports, the bolt holes are slotted and u shaped for a reason. Its sucking air staight in, not just what is coming through the intake, that causes the revving. Loosen the bolts and most likely you need to lift both the intake and header up some to make it align. gasket should still be fine.
 

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An easy way to check for vacuum leak is to get a can of starter fluid, start the jeep and then start spraying all around on the intake. If your problem is a vacuum leak then the engine should rev when you spray starter fluid on the leak. Although I'm not sure how well it will work with the engine already rev'ed up to 4k.

Also might check the IAC motor (I think OBDII had these). When I replaced mine on an OBDI system the engine reved really high when first starting but the computer just had to calibrate it. Took about 1-2 mins and the idle slowly came down. Not sure how long you have let it run but it just might need to recalibrate something.

Also you can check the TPS w/ a mulitmeter and the engine off, key on. I don't remember the exact readings. Google it and you should find the answer pretty fast or try cjoffroad.com, it will be on there for sure.
or carb or brake cleaner work well also..
 

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he said header not intake. headers wont cause vacum leaks.

check your codes and make sure you dont have a tps or iac code.
might want to reset your computer also.. you changed its parimeters and it might be freaking out.
Unless you have some ninja mechanic skills I've never seen, it's pretty damn hard to put a header on a TJ without taking all the bolts out of the intake as well.

Besides, if you hang out and pay attention on the lesser jeep boards, this question comes up about 3 times a week and the problem, symptoms, and solutions are always the same.

He hosed the intake seal when he reinstalled the manifold and when he fixes it, it's going to quit sucking air and idle correctly.
 

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like everyone else said. Check with a smoke machine (or spray brake cleaner on the seal). You will know really fast whats up.

You have an intake leak. You did something wrong. Fix it, move on, go break something. :D
 

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Unless you have some ninja mechanic skills I've never seen, it's pretty damn hard to put a header on a TJ without taking all the bolts out of the intake as well.
.
It doesn't take much to blowtorch the fender and frame outta the way to do the work. A little welding, bondo, and krylon and you're back in action way faster than taking off the manifold...dude, you gotta lot to learn about ninja mechanics.
 

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like everyone else said. Check with a smoke machine (or spray brake cleaner on the seal). You will know really fast whats up.

You have an intake leak. You did something wrong. Fix it, move on, go break something. :D
When you hose the header install on the TJ, you don't need a smoke machine, carb cleaner, propane torch or any of that other crap because the motor tries to hit redline when you start it.

It's the last thing you touched syndrome. It's the intake, it is screwed up and it is a vacuum leak.
 

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Unless you have some ninja mechanic skills I've never seen, it's pretty damn hard to put a header on a TJ without taking all the bolts out of the intake as well.

Besides, if you hang out and pay attention on the lesser jeep boards, this question comes up about 3 times a week and the problem, symptoms, and solutions are always the same.

He hosed the intake seal when he reinstalled the manifold and when he fixes it, it's going to quit sucking air and idle correctly.
its been a while since ive done it on a tj/yj. sorry my yj has a 350 in it. therefore on it you do not have to remove the intake manifold to replace the headers.

its been 5 years since ive done any header/intake work on a stock jeep motor.
 

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its been 5 years since ive done any header/intake work on a stock jeep motor.
When you did do the header/intake work, did you happen to notice that there is only one gasket for both and the bolts that hold on the header, also hold the intake? :p
 

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When you did do the header/intake work, did you happen to notice that there is only one gasket for both and the bolts that hold on the header, also hold the intake? :p

like i said its been 5 years.. i forgoteded.
 
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