neilo

I replaced the passenger side head on a 91 4Runner 3.0 and got it all back together and now it will not idle. I rotated the engine a dozen times or so and the timing marks lined up perfect every second revolution. I straightened up a few vacuum lines the I had wrong. It will run but will not idle. It runs a little rough until the RPMs get up and then it smoothes out. HELP!!!!!

addicted56

I'm in the same boat but did a complete engine swap. Tomorrow I'm going to add more coolant (knowing it is low) hopeing it is the coolant temp sensor. I idle crappy around 3-500 RPMs.

I'm always looking for other solutions, though just in case this does not fix my problem.

BUMP

Jay351

Make 100% sure your intake is sealed off. Mine had a small leak and it caused a 200rpm idle..

neilo

Not sure if this would do it but where the EGR valve bolts onto the manifold the threads on the lower stud got screwed up and I can not get the nut on it to get it to seal tight. There is an obvious exhaust leak but, not sure that it would make it keep it from idling. I also screwed up some of the threads on the end of the exhaust manifold and it is not sealed properly. I am going to put headers on it so I am not to worried about the screwed up threads. I was hoping to run it and make sure it runs ok while I am waiting for the headers to get here.

project91

The thing about replacing only one head is that you don't know the deck height of the other head, your new head may be slightly taller than the old one, possibly someone done a head job before and the heads had to be shaved down, if you have two different deck heights, your intake will fit and bolt down, but it won't seal correctly....I know thats not what you want to hear, but its worth putting out there...

Team420

hmmm....thats a good point...thnx for that, was going to do 1 head for a buddy, but now I think I'll tell him to do both. He has a burnt valve tho...not sure if that makes a difference.

neilo

You are right that is not what I want to hear. You are saying that there would be a massive vacuum leak? I will look into that and see if I can figure out if that was done.

neilo

I was thinking about the different deck heights and correct me if i am wrong but wouldnt there be a large coolant leak with that? There is coolant passages from the head to the intake.

neilo

Well i went in and rechecked the timing belt and it was off a cog so I fixed that. Now it runs much smoother but still will not idle.