littleredjeep

im not getting spark to the plugs but heres the kicker ive replaced the rotor button, distributor cap, coil, the control module under the distributor cap, crank shaft position senor, and ive tried a different computer with the same serial numbers. but still no spark. it is getting gas so any help would be greatly appreciated!!

ericfx1984

so what does this have to do with modified cherokee tech

littleredjeep

being that the jeep is "modified" i thought to ask in the "modified technical discussion" section.

partsguyct

Is there a relay that controls spark? I forget, if not disregard this.

littleredjeep

i dont believe there is a relay because in the diagram it shows a 60amp fuse and all the fuses are good, by the way its a 1993 jeep with a 1995 motor. still a 4.0 straight 6

ericfx1984

cool so what is modified on the engine so maybe we can help

littleredjeep

as far as engine wise modifications it has a full k&n intake new lifters,rods,pistons, crankshaft and the whole 9 yards. basicly the motor is brand new. the computer has also been sent and tuned. that wasnt the problem because it was tuned over 3 months ago and like ive said ive tried another computer with out flashing it and then flashed the other computer and still nothing.

partsguyct

Check the coil

littleredjeep

ive replaced the coil. and took it back thinking maybe a bad part and got another. its a head scratcher for sure

partsguyct

You need to find out where exactly your losing the spark, between the coil and cap or between the cap and rotor, or if its not even making it to the coil. Then work from there.

littleredjeep

i used a test light and found put its not making it from the plug that goes into the coil and traced it all the way back to the computer where no power was coming out of the computer to the coil plug wire. but like i said earlier i tried a different computer that matchs the numbers on mine. still not making it to the coil plug. if i had a melted wire some where shouldnt i be getting power coming out of the computer atleast?

partsguyct

Unless its not making it into the computer, there has to be a reference going in to tell it what's happening (usually the cps) which you can test with the same multi meter.

Lead Foot

Are your injectors not pulsing either? You said you had fuel but im guessing you just checked the shrader valve... If you arent getting spark from either computer, and you also arent getting an injector pulse, and the fuse is swapped out with a known good one or tested with a meter (not just looked at) then I would have to say it is your ignition switch.

I would also be inclined to say this is NOT modified tech. Standard engine diagnostics.

littleredjeep

the fuses i know are good and the relays i have not tried yet. ill just replace all the relays under the hood and see what happens. i have not tried to check the injectors. how i know its getting fuel to the rail is from disconnecting it off the rail and flipping the ignition and it pumps it out

Outlaw Star

Is the fuel pump working? If not check the relay. (3rd one from firewall)
Do you have spark? If not, check the CPS (camshaft position sensor) its inside the distributer and sends signal for coil to fire.
Do you have injector pulse? If not check the CKPS (crank position sensor) its located on the bellhousing of the transmission and sends signal to your injectors.
Hth good luck.