john deer green

Well i just purchased a 95 zj with a 4.0 off a guy for 300 bucks seems like a good deal. The catch is the guy said it wont start he has had it to the shop were they put on a new coil pack and plugs yet said it still wont get any spark. The last shop he took it to told him it was somthin internal with the motor that they would hafta rebuild the motor. Seems to me like it is an electrical problame of some sort for them to be thorwing coil pack and such at it i havnt acualy had the hood up on it yet to check it out just woundering if yall had any suggestions. This will be my first time messin with a newer 4.0 my old xj is a 89 and i know my way around it perrty well just tryin to get some opions on the newer one Thanks

squazz

crank position sensor....? located on top of bell-housing

john deer green

thats what i was thinking it seems to be a common problame with them im hopin i can get it runnin cheap but heck even if i cant i can rebuild the motor and still be under 1500 bucks and have a new rig

dave1123

That was my thought. At $300 you can't go wrong. You could part it out and make more than that! My guess is crankshaft position sensor or cam sensor.

You should still have a distributor on a 95, yes? pull off the cap, inspect the rotor. and crank it to see if it's even turning. If it is, you can eliminate the timing chain or oil pump drive gear as a possibility. If you've got spark, check to see if you have power to the injectors. Check fuel pressure.

Check the ASD relay. This cuts off fuel and spark. try replacing it with one of your headlight relays.

drakan1908

Friend of mine bought a 95 zj for 100.00. Same problem ......needed a fuel pump

dave1123

Yeah, but that can be determined by a little gas down the throttle body, right?

john deer green

thanks for the suggestions im goin to trailer it home this weekend hopefully it wont take much to get it goin all i know about it is that he replaced coil pack andand plugs so my guess it had been diagnosed as not gettin any spark lol

KD3NE

Fuel pump has nothing to do with NO SPARK.

Probably a terminology problem but I do not think 95's has coil packs, I think you meant an ignition coil.

Ignition Coil feed high voltage to the distributor which itself send the high voltage to the plug.

I would check the OUTPUT of the Ignition Coil to make sure it has no spark, if no spark coming out of the coil then look to the sensors mentioned.

If it has spark on the output of the coil, look to the distributor cap and rotor.

Also, check the wire from the coil to the distributor.

I've had two different jeeps fail because of NO SPARK.

#1 was sensor on the bell housing
SYMPTOM: Jeep would die while driving but restart.
The randomness is what motivated me to change the sensor. It was the problem. Not the easiest to change, at least on the XJ .... but I had no problems doing the job using a 3/8" drive AIR ratchet and extensions. Not much room under there to swing a manual ratchet.

#2 was ignition coil
SYMPTOM: Jeep died while driving and no restart.
Ignition coil is about $30 and easy to temporarily put in place to test.
I bought one on a whim, tossed it in and it worked.
If it had not been the problem I would have kept it for a spare

dave1123

My 97 ZJ had a coil and distributor, My 2000 WJ has coil packs. Both are 4.0s

You can test for the presence of fuel pressure by depressing the shrader valve in the fuel rail. It will spray out, so don't do it while running!

john deer green

KD3NE thanks for the advice me and my buddy are gona try to pick it up tomarrow evening ill let yall know what i find then im gona start a build thread on it and post some pics

squazz

Ever get it running?

1slo_camaro

curious myself.... I did have my 98 zj shut down randomly put plugs, wires cap rotor, crank and cam sensor and even a new dizzy and couldnt get it to start (no spark condition) tried a known good computer. checked all my fuses couldnt figure out what the hell was going on. put a new motor in in and now shes running perfectly fine.... absolutely NO CLUE what happened to it

squazz

Timing chain on your old motor broke?

1slo_camaro

nah dude, timing chain was good didnt jump any teeth, good compression valvetrain was good. between myself, my father, grandfather and about 4 other gear heads NOBODY could come up with a reason.... the Dizzy in that motor is in my motor now runing perfect

Parsnip

Asd relay tripped. Did you try jumping those terminals?