2000 Jeep TJ will not crank

Zane Pearce

Zane Pearce

Well-Known Member
Joined
Sep 28, 2009
Location
Lincolnton NC
Per my previous posts I just installed a rebuild 4.0 into my tj, got the proper block and everything is installed. When installing everything into my long block i set my cam position sensor for timing as accurately as I could referencing my FSM and youtube. The engine is now completely installed and will not start up, the engine cranks over and will backfire/pop but wont fire up. There have been a couple of times it sputtered as if it was going to start but still nothing.

I went ahead and ordered a new crank position sensor and cam sensor and i'm gonna replace both today and try and confirm my timing is set properly for the 3rd time. I will also check for spark and if need be ill pick up a guage to check for fuel pressure but i have no reason to believe anything is screwed on my fuel side as nothing was actually disconnected.

Also I believe my grounds are good but ill have to check and recheck them too. I have heard various stories about issues with initially getting everything properly set to crank up a rebuild 4.0 properly and I'm looking for any advise on other things to check if changing the sensors and setting the timing dont make it fire right up, anything that would keep the dang thing from starting up i'm down to hear.

Thanks
 
Bled the fuel rail yet? (theres a schrader valve on the end)

When I rebuilt mine, the culprit was the cam position sensor. I can't remember if it wouldn't run, or was just running terrible, but that was 13 years ago...wow. But apparently the cam sensor drive or gear had worn tremendously in 47k miles and needed to be replaced. Replaced it and it cranked right up and ran like a champ.
 
hmm interesting, i have a new sensor but not a new drive, and no i havnt bled the fuel rail, i never disconnected it, just removed it from the manifold and held it out of the way during the swap
 
Here's how to install the cam sensor/oil pump drive. Will work every time (if that's the issue)

-Remove #1 plug, put finger over #1 plug hole, spin engine over by hand until compression is felt. Line up timing mark on harmonic balancer with mark on timing cover
-Remove cam sensor from oil pump drive, look on the bottom of the OPD for the little hole (approx 1/16") that goes up towards the tone wheel. Insert a toothpick, small screw driver, etc through that hole and into the corresponding hole on the tone wheel. The OPS is now "timed"
-Look into the OPD hole in the block, using a flatblade screwdriver, rotate the oil pump to about 10:30
-Drop the OPD into the hole making sure the OPD sits flush to the block. If it doesn't, rotate the oil pump a little either way (10:00 or 11:00)
-When the OPD is sitting flush, the connector end of the cam sensor will be pointing towards the firewall,parallel with the engine block.
-Remove alignment tool (toothpick or whatever you used) and tighten down the 13mm bolt
-Fire up the engine and enjoy
 
Changed out the sensors and reset the timing on the cam sensor, jeeps cranks finally! run decent but it's pretty low on power and I'm guessing it needs to be synced with the drm tool from a stealership, also I have a exhaust leak but I figure that wouldn't cause significant power loss, has anyone had any experience gaining normal power back after getting the engine synced at a dealership?
 
Had the cam sensor 180 out, it would run, but very low on power and hard to start.

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If it's 180 out it would be running lean likely because fuel would be injected at a closed intake valve. Waste spark setup and firing order allow it to run 180* out.

If you installed the sensor according to Jody's instructions, it is in time unless the crank rotated almost a whole revolution after it blew your finger of the plug hole.

If you suspect the oxygen sensor, unplug it and go for an open loop run. If it runs with restored power your oxygen sensor is probably failed.. I've seen some sensors not report faulty and throw afr off, but that was usually on imports.
 
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