got a tough one for you guys

[redcj7304]

buddy of mine has a 88 yj,carb, and its not getting any spark...lots of fuel, new cap and rotor, power going to the coil, tried 3 different coils..still nothing...no broken plug wires, 12 volts going to coil and when starting still 12 volts but nothing coming out of it and nothing coming out of the others we tried. all fuses are good. all connections are clean and tight, i'm just puzzled...any1 here got any ideas...we've been working on this thing for almost 12 hours and still nothing...it did run for 5 minutes than when he parked it it didn't start again..lets see how u yj guys are good...i got a cj so..

[redcj7304]

oh and sorry he's got the 4.2 and 5spd...just for more info

[jbolty]

Could be the ignition modual; it's a common problem. Located under the washer bottle. Some auto stores can test it for you.

Not too expensive. Or, you could do an HEI conversion.

[wcjp]

Also, cps-crank position sensor

[jbolty]

No CPS on the 4.2, carbed.

[shooter207]

If it is the ignition module, could be a good time to nutter

http://www.jeepforum.com/forum/showthread.php?t=522262

Likely not a street legal option but easy to do and improved performance on my 88.

[jeepsr4me]

Could be the ignition modual; it's a common problem. Located under the washer bottle. Some auto stores can test it for you.

Not too expensive. Or, you could do an HEI conversion.
x2

[redcj7304]

well ignition module is fine...so thats not the problem...so i'm getting 12volt to the wire from the coil to the cap with key in on position...as soon as i crank the engine over the voltage slowly goes to 0....tried 2 more coils...nadda...getting plenty of power to the coil and lots of power to the module but one wire is ready only 5.68 volts.. while 2 are ready 12volts.???

[redcj7304]

anymore idea's....what exactly is the green wire on the cap for...does it act as a ground?cuz i'm getting voltage in it..

[jbolty]

some info in the diagram I posted above.

can't think of anything else aside from an issue inside the distributor.

I went HEI and never looked back.

[redcj7304]

what exactly is hei

[jbolty]

what exactly is hei

distributor out of a chevy pickup

I got mine here, http://crtperformance.com/html/jeep_amc_hei_s.html

but you can build your own.

High voltage spark. One wire hookup

[redcj7304]

yea i'm gonna check for a broken wire somewheres first...

[jbolty]

yea i'm gonna check for a broken wire somewheres first...

There are some electronics inside you existing distributor as well. not sure how to test it though.

[Rebel Wrangler]

buddy of mine has a 88 yj,carb, and its not getting any spark...lots of fuel, new cap and rotor, power going to the coil, tried 3 different coils..still nothing...no broken plug wires, 12 volts going to coil and when starting still 12 volts but nothing coming out of it and nothing coming out of the others we tried. all fuses are good. all connections are clean and tight, i'm just puzzled...any1 here got any ideas...we've been working on this thing for almost 12 hours and still nothing...it did run for 5 minutes than when he parked it it didn't start again..lets see how u yj guys are good...i got a cj so..

I'm having the same problem, but I've got a same year 2.5 4 cyl TBI..... Ignition coils replaced 3 times, module is 7 months old, ground wires are clean, Distributor rotor and D. cap are both new, cables and spark plugs are brand new, idk what's goin on either. I'm thinkin the distributor

[redcj7304]

still no spark....brand new ing. module in today and nothing...i'm getting frustrated and not paying shop rate here thats at 106$/hr

[jeepsr4me]

Pop the dist cap and mark the orintation of the rotor. Go bump the starter just for a second and see if it is turning. I had one strip out the gear the rotated it. Also I believe autozone can test your distributor for free. Just got to pull it. If not Go to junk yard and get a distributor. Because if you got power to coil and still no fire after the module change then it only leaves 1 other thing.

[Rebel Wrangler]

Fixed mine bout a week ago, it was the CPS

[jeepsr4me]

88 models dont have cps.

[mikibbee]

the rotor has a little key on it i think to keep it from spinning a buddy of mine had his break off and it would spin if you watched it but not at the right speed. it was slipping

[Rebel Wrangler]

88 models dont have cps.

Then please tell me how I changed my Crank position sensor if I don't have one? That would make me feel a lot better about what I replaced, not really, but I'd like to know what it was then.

[jbolty]

Then please tell me how I changed my Crank position sensor if I don't have one? That would make me feel a lot better about what I replaced, not really, but I'd like to know what it was then.

you have a 2.5, the OP has a 4.2.

2-5 = cps
4.2 = no cps

[redcj7304]

changed the ignition switch yesterday...still nothing...how can i test the pickup coil...in the distributor cap???its all i got left in ideas to check...i've changed everything...rotor turns....i get power to the coil but as soon as the i crank it the coil itself loses power at the output(where it goes to the Cap)

[sikjeep]

check the power wire to the coil, mine was bad and looked fine just looking at it,

I bypassed it with a piece of new wire and started right up

[Al Johnson]

Possible you may have a bad starter relay (solenoid). Coil voltage passes thru it. Replacements are dirt cheap if you go generic.

[jbolty]

You have replaced a lot of parts. Each of those things has a defined test procedure in the service manual. Instead of guessing and throwing parts, time and money at this why not follow normal diagnostic procedures. just sayin. :2cents:

[redcj7304]

i did...and service manual doesn't say much...i got the haynes manuel

[jbolty]

Get a factory manual and follow it. If you are not getting power to the coil why would you change the ingition switch, without knowing it's bad? You could test the circuits in two minutes with a volt meter.