ZJ no start continues

[dunl]

Okay, I can't get my 93 ZJ V8 to start. In the past two times this happened, it was the ignition coil, so I replaced it, and this time it wasn't the issue (no biggie, I now have an extra for when the POS goes the next time).

It's been sitting for several months (due to it not running), so I checked the Schraeder valve, and there was only a little pressure. Re-charged the battery, let it sit in the on position for a bit to get fuel up the lines, no start. Checked the Schrader, and lots of fuel seeped out - appears the pump is working. Opened the intake, put a little fuel down there, no start.

Where's my next check? CPS?

Thanks.

[HIWYH8R]

If your getting no spark then it is likely the crank sensor. They aren't too expensive so if that doesn't fix the problem you at least have a spare. CPS's are common for going bad, and not just in jeeps. A bit of a pain to change on some jeeps. Also you did check all your fuses with a test light right?

[ramtuff]

Okay, I can't get my 93 ZJ V8 to start. In the past two times this happened, it was the ignition coil, so I replaced it, and this time it wasn't the issue (no biggie, I now have an extra for when the POS goes the next time).

It's been sitting for several months (due to it not running), so I checked the Schraeder valve, and there was only a little pressure. Re-charged the battery, let it sit in the on position for a bit to get fuel up the lines, no start. Checked the Schrader, and lots of fuel seeped out - appears the pump is working. Opened the intake, put a little fuel down there, no start.

Where's my next check? CPS?

Thanks.

you really need to check your fuel pressure in a more accurate way. unless you have a minumum of 40 psi(i think) your injectors will not open. you will need a fuel pressure guage with a fitting to attach to your fuel rail.

[ramtuff]

try dumping a cup full of fuel down the throttle body and see if it will start and run for a few seconds.

[dunl]

Thanks Chris, I'll check into borrowing a fuel guage from AutoValue or PartSource this weekend.

A cup FULL of fuel???

[cLAY]

Is it trying to fire at all or just spinning? If its firing even a bit then its probably fuel related. If its spraying out of the schrader and not firing at all then I'd agree that its the CPS(or coil).

Good luck changing that @#$%@#$ thing. Its nearly impossible to get at on a V8 and isn't cheap either. Took me 2hrs, a whole wack of different adapters and extensions and by the time I was done my arms were all brsuised, scratched up, and bleeding.  :evil:

And in the end it wasn't the CPS it was the coil!  :cry:

If you own a V8 GC and are taking the tranny out or exhaust manifolds off do yourself a favour and change that little bugger. You'll be kicking yourself later if it goes.

[Trouble Maker]

Maybe...............

http://www.jeepforum.com/forum/showthread.php?t=378178

[dunl]

Thanks for all the tips guys, going to give it another shot today.

TroubleMaker, I did see some infor on those capacitors, but I couldn't find a write up, so thanks - that link is great.  The ECU/PCM is on my morning table (wife is pleased I'm sure), and cracked open.  Looks like one of the capacitors is leaking, so after my Timmy's I going replace them.  Let you know how it works out.

[dunl]

One question....two capacitors are the 220uf 25v, but one that I see is 400uf -isn't it supposed to be 220uf like the others?

[dunl]

I changed two out of the three, left the 400uf one alone.....



And guess what fired right up?  

[Trouble Maker]

I changed two out of the three, left the 400uf one alone.....



And guess what fired right up?  

Right on!

I think the caps are board version specific, diff boards have diff cap ratings. Looks like a good alternative to paying through the nose for a new PCM.

[dunl]

Yup.  From the price of a new PCM ($780), looks like I owe you a beer...or a case.  :lol:

[dunl]

And I just got home from Rocky with my wife, after the ZJ died on me again.

I'm guessing the capacitors are fixed, and something else short circuited.  :evil:

[Trouble Maker]

One of the local guys here had intermittent problems with his 5.2 Dakota. Spent a bunch of money at the dealer and they couldn't fix it. He finally pulled the PCM to engine harness and went through it, found some corroded splices & bad connections, resoldered and resealed it and it runs like new.