ZJ: Engine wants to start but....

[InlandZJ]

Well went to start my jeep and it cranks plenty but almost starts but nothin. Changed the fuel pump and checked the battery connections sparg plugs/wires sending unit maybe or idle air fuel mix not sure here it had no signs leeding to this bump in the road
any help or direction i'm going through my manual but still trouble shooting

[aw12345]

First does it have spark, if so does it have fuel pressure

[6spdYJ]

A buddy at work had this same symptom. Make sure you have fuel pressure and spark. If you do a compression test and the numbers are inconsistent within one cylinder, check the cam drive sprocket. The bolt that holds this in can walk out - also, if the engine was assembled with a roll pin (where there should be a dowell) the roll pin can compress and fall out, allowing the cam timing to go wumpus on you.

[InlandZJ]

AW12345 I think its getting spark but some how im leaning towards the fuel preasure. I sprayed some carb cleaner down the throat and cleaned out the gummed up area but started to after a quarter of the can sprayed then it cuts out quickly. 6spdYJ not sure on were to look as far as cam drive spocket is it at the front of the block ? or the roll pin if it was equipt with one

[6spdYJ]

Like Art said, first spark, then fuel. If you don't physically check for spark, troubleshooting can get a lot more difficult than it needs to be.
Looking back at your post, have you verified the spark? The Crankshaft Position Sensor located on the back of the bellhousing (at about 1:00 position looking at it from the front) is what initiates the spark signal to the ignition system. If this guy fails, you'll get either no or intermittant spark. Swap it with a known good one first. If you still don't have spark, go to the coil.
The cam sprocket is under the timing cover on the front of the block. You have to pull off the fan and balancer to get to it. You have a sprocket that is pressed onto the snout of the crankshaft (it's held on by the balancer and driven by a woodruff key). That one is what drives the timing chain. The timing chain reaches diagonally up to the passenger side of the block to a bigger sprocket. This sits under the cover that is roughly shaped like a pear sitting on it's side. So, the cam sprocket itself is held on to the cam by one center bolt, with an off-center dowel pin (or roll pin). Google images for Jeep timing chain.
This thing isn't much fun to have to get to in a hurry and can cause a lot of grief if it's on a daily driver. Hopefully it's not. This does lead to the question of how many miles are on the engine and what you were doing when it quit (6000RPM?). If the nylon tensioner wears out and the chain skips, your valve timing goes out the window.

[InlandZJ]

I will check the the cps in the afternoon tomorrow the jeep has 207 thousand miles on it and i was just having lunch with my wife when we were leaving out of nowere it just happened and i almost went wheeling this morning with some other jeepers .. good thing i didn't I hope its not this indepth and something i could do my self were i live in a gated association community the life of a jeep owner : )

[6spdYJ]

Another thought is to simply check the cap and rotor. Keep us posted. We want it running as much as you do

[InlandZJ]

Another thought is to simply check the cap and rotor. Keep us posted. We want it running as much as you do

I replaced the cap and rotor and fuel filter today and fail but wheels are turning as i gather info and other thought for some amo. When i pop the hood is the cps behind the engine on the bell housing and is it easy to get to from under the jeep or from above?

[InlandZJ]

6spd do you have a pic of the cps on the bell housing? I dont have alot of time tomorrow and tuesday i have a meeting im hoping i could get this figuered out before tuesday morning. Thanks for the replys

[6spdYJ]

http://www.novak-adapt.com/knowledge/420_to_amc.htm
This will show you the general position of it. I don't know if the ZJ has one or two bolts. It's either a 10mm or 11mm box end wrench to pull it out. The harness will be held onto the injector rail by a metal clip - retained by a nut. Just pull the bolts out and it will lift straight out. Just be gentle on the wires.

[InlandZJ]

Fixed! Wow the jeep is starting to cost a little in things just breaking down naturally. Fuel pump! I had a gut feelin at first but did not have any facts to back it up ohwell 500 later and another jeep is back on the road again. I am happy : )) Thank you guys for suggesting what it could be and all the feed back,

C you when i see you peace

[Jeeperator]

$500 for a fuel pump!

[Lumpy Grits]

$500 for a fuel pump!

X2...WTH? Why so many $$$
NOW, go and change your fuel filter too.
LG

[InlandZJ]

X2...WTH? Why so many $$$
NOW, go and change your fuel filter too.


LG

This was for the fuel pump and fuel filter installed while i was at work but trip on this i drove the jeep 2 and 1/2 days and yesterday got home and was getting ready to go to the oc and it did not start same problem as before checked the fuel preasure and it just trickled out of the fuel rail it sprayed at first then i cranked it shot some starter fluid down in the carb and started but then ran rough and cut out. Pissed i have to tow it back to the master mind that worked on it and put some static behind this cause i paid a bunch and now its doing the same thing. Good thing i was not on the 91 stuck loaded with tile. Maybe he replaced it and it sucked up some sedements from the bottom of the tank???

[Lumpy Grits]

Ask the dealer just WHERE did they get the f/pump?
Factory OEM or some CRAP from Autozone or the like.
NAPA would be good.
Did you even see the f/pump that they "said" was yours?
Ask for the PO of your "new" pump.
The tow is on their "dime" and make sure they know this.......
Good luck,
LG