JQJ

Hey jeeple! new to the forum but long time reader. Ive had an issue that doesn’t seem to fit any posts I’ve come across, but is similar to several.
A couple months ago my manual 4L 1995 Cherokee began dying immediately after starting. A total shut off about .5 seconds after it fires up. I can almost always get it running by re-hitting the ignition in that .5 seconds. Sometimes it takes a few goes, and if im not quick I get a nasty sound from the starter. Once I get it going it stays going, haven’t had any idling issue or other shutdown issues.

So here is what I’ve tried so far:

New battery
New starter
Cleaned grounds
New rotor, cap, ignition coil, plugs&wires
New cps
New tps
Cleaned iac
Tested all relays
Tested fuel pressure at rail and seems like the fuel pump is working fine.

I am at a loss.

Any input appreciated!

PatHenry

Sounds like a bad ignition switch.

JQJ

thanks! I'll take a look into it and report back

JQJ

Update: Visually checked the ignition switch and appears normal (not burned), but I'll have to test later on in the weekend, because this problem is intermittent (1 in 5 starts and then persists for the next 3 or 4 starts) I'm not sure what to look for in the test. In the meantime, the problem has a new mutation. Last night and this morning after starting up normally it shut off after about 5-10 seconds when I was just sitting in Neutral. Started right back up each time and drove normally.

After doing a bunch of reading, I figured it could be the PCM so I've been on the look out for one just in case, and came across one for the same year and model (95 sport), only difference being the one at the junkyard is automatic and mine manual. It was cheap enough so I picked it up but can't seem to find a definitive answer about whether a swap will work.

thanks again!

JQJ

ignition switch replaced, so far no starting issues, will give it a few days but hopefully this is it!

PatHenry

Nice! Glad to hear it and keep us posted.

A computer from an automatic will not work correctly with a manual. It --may-- not matter in a pre-OBD2 such as 95, but I would guess that the lack of the various automatic components (TCM, NSS, etc) would be a problem. With an OBD2 model year (Jan 1 1996 and later) it will throw error codes which will prevent the vehicle from passing inspection.

With ECM's, you need to replace with the exact same part number. (That said, the P.O. of my 5-spd 95 put the incorrect ECM in (it's still from a manual Jeep though), and so far everything runs fine..) I was able to call the dealer and have them get me the correct ECM part number.

JQJ

Looks like it was the ignition switch.
Haven't had a problem since I put in the new one.
thanks again!

PatHenry

Nice!! Thanks for the update.