Good afternoon all. Hope your week has gone well. Mine started well getting the new motor to drop in and get all hooked up but when I started it some issues came up. Now I'm a newbie when it comes to Jeeps but have turned wrenches for awhile so I do have some knowledge on how things are to go but first experience in this deep of repair on a Jeep. One is that I don't have any fuel pressure at the rail but it starts so I'm guessing a bad gauge from HF go figure huh. Second issue which is the most important one when started the engine rev's way high like 4k and up. Didn't let it run like that only for a couple seconds b4 shutting it down. A little history on this 2000 TJ. Bought it with a blown up 4.0 and PO was long gone so no talking to them for any history. Replaced the engine with a long block as well as all the other normal maintenance items ie; hoses belts crank sensor ISC motor water pump thermostat fuel injectors. I had the cam sensor out as well and I think it's in correctly. The only thing I didn't do was to phase that sensor because I don't have that tool yet. Any thoughts as to why it revs so high when started? I can't wait to hear all your thoughts. Thank you for your help and time.
New engine issues
- Thread starter Blue 2000 TJ
- Start date
Yea I agree to the vacuum leak Thought I was good but guess not One positive I know the bolts won't be tough to get out this time. Thanks for the thoughts
Yeah I'd smoke test it to look for leaks in your vacuum lines and intake manifold. Did you say the IAC was replaced? If so, what brand because the IAC controls the idle.
It's a Standard Motor Parts item. I sold that brand in the 80's and we had very few problems with them, I'm in NW Nevada so the brand name stuff is a little harder to come by here.
Just spit balling but you could probably unbolt the IAC, plug the hole, slightly open the throttle and start. If it does the same thing, it's not the IAC. If it doesn't rev high, it's something with either the IAC or it's circuit.
My gut says huge vacuum leak.
My gut says huge vacuum leak.
Last edited:
Agree with the vac leak I'll try the IAC idea b4 tearing everything apart to be sure Thank you for the thought
JKP
TJ Addict
Your intake manifold is not seated correctly on the pins resulting in a massive vacuum leak.
JKP
TJ Addict
JKP
TJ Addict
Nothing other than be sure the holes are clean and try to get a visual from above and below that it's seated.
Well it's done and running It was a vacuum leak as suggested Those dowel holes where the issue To fix the problem of not registering correctly I chamfered the back side slightly and it popped right on. Thanks for all your suggestions and insight.