pett359

ok, so I bought a 93 jeep Cherokee 4.0 with the head off under the assumption that just a head gasket was needed. Not my luck piston #2 was cracked so y'all know the story pulled the engine out rebuilt it. That was the easy part ! Engine is back in GREAT !!! After figuring out were everything plugs in and also figuring out how to hard wire the distributor( that's another bi%#h session for another day) I get her runing and ideling OK. Here's the part I can figure out it is smooth at ideal and up to just about 2100 rpm then it misfires like crazy, it sounds like it has a studder box on a drag car. It also does not have any power at all, no codes are thrown, keep in mind when rebuilding I installed a new distributor, new crank sensor, new coil, new tps, and new plug wires and plugs. With my scanner I can not see anything out of the ordernary all voltages check with in normal operating range. And the fuel pressure is within it's psi range

So do y'all have any idea to why this is going on?

Thanks in advance!

pett359

Oh and it's auto and 4wheel drive

Bustedback

Recheck the firing order. Check the fuel pressure.

cruiser54

Do this first:

Setting Your 4.0 at #1 TDC
　
With #1 spark plug removed, turn the engine over clockwise using the 3/4" front crankshaft bolt. You will see the degree marks on your front cover. Mark the 0 with chalk or white-out.You will see the timing mark on the balancer. Mark it with chalk or white-out. While turning the engine over, put your finger/thumb over #1 spark plug hole. As the mark on the balancer approaches the marks on the front cover, if you are coming up on #1 TDC, pressure in the cylinder will push on your finger. If there's no pressure, you're at #6 TDC and need to crank the engine over until you see the marks coming together and you get pressure. Set the mark on the balancer to the 0 mark on the front cover.


This second:

http://www.angelfire.com/my/fan/dist_index.html

pett359

Ok so this is how I timed it to begin with but just to make sure I will do it again. Is there any other ideas y'all might have?

cruiser54

Firing order should be checked as mentioned alreasy.

Parsnip

That dizzy probably just needs to be clocked a tooth or two, like cruiser said double check firing, but to me it sounds like its indexed off by maybe one tooth, and your ecu can compensate for that only so much (why it would run smooth up to 2k) before it goes to the dogs.

cruiser54

My thoughts exactly. If I had a nickel for every time someone put a different motor in, and swore they had it timed right, and found out later they were wrong, Id be a wealthy man.