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Jeepingolfer 04-03-2011 10:08 PM

Engine wont start
Ok all, have a problem, and about at the end of my wits. We have a '99 TJ with the 4.0L that we recently pulled the engine out to do a complete rebuild. Engine had a blown head gasket, so we figured we would just go ahead and go thru and do a rebuild. Everything went fine, all back together, but the darn thing will not start. Here are the details so far... First we are absolutely sure mechanically the timing of crank and cam is good. It is getting 50 psi to the fuel rail when cranking. Coil is new, spark plugs fire when cranked. Crankshaft position sensor is brand new (already thought that may be the issue). The engine turns over and over but will not crank, sometimes it sorta stumbles a little bit, almost like it's trying to start, but not a thing. Leads me to believe it's a timing issue, but these things are completely computer controlled, so what gives? any ideas would be greatly appreciated. Thanks!

JeepJKRiders 04-03-2011 11:07 PM

What do you mean everything went fine? Did it run for some time?

Jeepingolfer 04-03-2011 11:18 PM

Sorry about the confusion, no never would start, just meant the engine went back together with no issues. also forgot to mention it's an automatic tranny, and was rebuilt using same block, head, pistons, crank and cam, just refurbished and all new bearings, rings, etc

JeepJKRiders 04-03-2011 11:25 PM

Have you tried moving the timing a few steps offset in both directions?

JeepJKRiders 04-03-2011 11:51 PM

Ok I'll explain a little. Are you sure you have tight compression in the motor. Check oil compression. I had the same type of problems with my older Jeep. Tried moving timing offset, it cranked up, but smoke was all over the place from the tail. I did breakdown again, after oil compression levels were low. Found a small hair line crack under the head between cylinder ports. Replaced the head and fixed.

Jeepingolfer 04-04-2011 01:12 AM

Can't move the timing. This is a completely computer controlled engine, the distributor is tabbed so that it only fits in one way, and is not adjustable. As far as compression goes, all cylinders have been compression tested and all are well within range.

JeepJKRiders 04-04-2011 10:17 AM

Ok how long was your sitting before you decided to work on it? Take the battery to a shop and have it crank tested. How old is the fuel? Are you sure the fuel pump is working?

Blacksurt 04-04-2011 10:34 AM

I'm not sure how the distributor works on that, are you sure you were on the compression stroke 1st cylinder when you installed the distributor? You could be 180 out.

JeepJKRiders 04-04-2011 10:49 AM

Blacksurt could be right about that.

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