How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Chris Your Own Question
Chris
Chris, Shop Foreman
Category: Jeep
Satisfied Customers: 13017
Experience:  Jeep Certified Master Tech
12365498
Type Your Jeep Question Here...
Chris is online now
A new question is answered every 9 seconds

Second opinion] - 4.0L '01 -Well, my son and I had his

Customer Question

Second opinion] - 4.0L '01 -Well, my son and I had his engine rebuilt and put it back in. We had a mechanic helping us, but after the manifolds were put back on, he was done. So we finished up, and fired it up, we had break in oil in it. It fired right up to 2500 and would not come back down. I was told to let it run so I ran it for 15 minutes. We started replacing sensors, and we are to the point of not having an idea. The mechanic only put 7 of the 8 manifold bolts in so I pulled the manifolds and put a new gasket and all of the bolts in. Now, it fired up one time and shot up to 4000 and I shut it down immediately. What should we check?
JA: Is this your first time dealing with this issue? What size is your engine?
Customer: 4 Liter, ;01
JA: What is the model of your '01 Jeep?
Customer: Wrangler
JA: Are you fixing your Wrangler yourself? What have you tried so far?
Customer: 4.0L '01 -Well, my son and I had his engine rebuilt and put it back in. We had a mechanic helping us, but after the manifolds were put back on, he was done. So we finished up, and fired it up, we had break in oil in it. It fired right up to 2500 and would not come back down. I was told to let it run so I ran it for 15 minutes. We started replacing sensors, and we are to the point of not having an idea. The mechanic only put 7 of the 8 manifold bolts in so I pulled the manifolds and put a new gasket and all of the bolts in. Now, it fired up one time and shot up to 4000 and I shut it down immediately. What should we check?
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 3 months ago.
Category: Jeep
Expert:  Chris replied 3 months ago.

Hello, my name is ***** ***** I will assist you today. You have a huge vacuum leak somewhere. I have seen issues where the intake manifold does not line up with the dowel pins on the cylinder head and then does not sit flush. That in turn causes a big vacuum leak. Check that very closely. Use a mirror if you have to. If you are sure that the intake is not the problem, then look for another vacuum leak. I hope this helps and let me know what you find.

Chris