engine redlines!

[jahswoop]

Swapped the old 4.0 for a new one in my 2000 Cherokee and when I start her up, just revs high to redline. Manifold seems snug, not sure about if the sensors will cause this or not. Need help, thanks

 

[Bounty__Hunter]

Welcome to the Z. Sounds like a vacuum leak.

 

[jahswoop]

No vacuum leak, I don't think it would rev to redline with a vacuum leak unless it was huge, which would be visible and we tripled checked everything. The Idle Air Control Sensor was carboned out and stuck open. I changed the sensor, but now the timing is off. I can not figure out how to get this engine timed. Do you know how or anyone that knows how to get the timing right? Thanks

 

[TorqueWinsRaces]

A 2000 is an OBDII vehicle. The timing parameters can only be changed with a computer.
What is it doing that makes you think the timing is off?

 

[SteelHeadz]

The Cam and Crank Sensor must be Synchronized after replacement by means of the DRB3. The range specification is 0 Degrees.

 

[jahswoop]

It just sounds like the timing is off, backfires. So I must have the DRB in order to get it synchronized?

 

[SteelHeadz]

I would normally say yes, but if you have the patience of doing it by ear , you might be able to get by without taking it to a dealer.

 

[jahswoop]

We tried several times to sync it, a couple of different ways, but we are running out of patience and time. I'm going to take it to Jeep Masters here in town. Hopefully it's just a 100$ hook up the computer thing...Thanks for the input fellas.