Topic: Fire to Coil but no spark

[hawks]

I am new to this iste but have found it very useful...
I am helping a friend of mine try to fis his 94 ? CJ7 It was running good about a year ago his son was going down the road & it died.
We just now getting time to work on it.
WE can get power to teh coil but can't get spark out of the coil.
we have just purchased a new coil and still no spark.
So far  the have replaced the Pick up's
Coil and Distrbutor.
Also had the computer sent off and checked \ fixed.
So any advice on what to check \ look at?

My friend is a Mechinc for about 20 years and this has stumpped him.
That's why I'm turning to the Jeep pros here at 4bangerJp...
Oh yea it does have a 4 banger and is all stock... just in case anyone was wondering
Thanks in advance

[sharpxmen]

it's a bit confusing

'94 CJ7 with a 4cyl engine.

If it is indeed a '94 then would be a YJ and i would look at the crank position sensor and if that's not it then might be the cam sensor or the PCM although there might be other reasons for which the PCM does not issue a spark but in that case you would most likely get a code (check engine light) and if you don't then could be that there's no power or ground to the PCM (computer).

if it is a CJ7 i'm not familiar with it.

[Torch_Ind]

a 94 cj? or Yj. i'm guessing yj if it's computerized.

you probably have power to the coil but do you have the signal side? the leads going to the coil if you put a test light on the circuit when turned over should flash.

you could look in to the crank signal also check the sensor for oil or dirt on it. it bolts in back at the transmission/ flywheel area on the intake and exhaust side. also check to see if the wiring fell on the exhaust and burnt throw.  

these problems for me I almost have to be there to help check. as they are some what complex to describe how to check and test

also check the auto shut down relay

there is also shop manuals on this site with all the wiring schematics

[Torch_Ind]

crank sensor location.






relay center in front of battery.




Relays and fuses in center. even look under it for green death.  I have had problems starting mine or having it stall and I took out all the relays cleaned out the mud and cleaned up the contacts on the relay and in the box and it was great after!!

[Torch_Ind]

also check your power cable coming from the alt it may not be getting good voltage throw it at the connector roughly mid of the cable I think it was for quick connect for engine removal.

also I had problems with the connector at the coil. I got so frustrated with it I took out the stock style coil and added eye connector ends and went to the old school style coil that the wires actually bolt on.

[Torch_Ind]

hope I have giving you enough info to start anyway lol