1. Home
  2. Jeep and Willys (new and old)
  3. 1990 jeep cherokee no start

1990 jeep cherokee no start

Hey guys,

I've got a very frustrating problem here. Customer brought in a 1990 Jeep cherokee limited, 4whldrv, automatic. We replaced the engine with one from a 1996. All the appropriate electronics were switched from the old engine to the new including, distributor, cap, rotor, coil, CPS, flywheel, intake and exhaust, all injectors (already on old intake). The problem is we now have a no start/no spark condition. This swamp is common at our shop, (newer 4.0L into older jeep) and always goes off without a hitch. This is the first time I've run into this. We've replaced the CPS, coil and ignition module check out O.K., Distributor checks out. We even put all the suspect parts into another jeep and they worked fine. The computer has also been replaced but to no avail. Any input would be appreciated. Thanks. Jesse

Reply to
spydey
Loading thread data ...

That leaves wires! Check all the grounds that are on the passenger side bolted to the block.

JoBo

Reply to
Jo Bo

You'd think so wouldn't you. However, I did check all these and the grounds are great. Turns over via starter with authority.

Reply to
spydey

NEW INFO, fuel pump relay does not activate on cranking. When we jumper the ballast resistor wires it chatters like crazy.

Reply to
spydey

K....injectors aren't firing. Can manually operate relay to activate pump but when cranking the injectors won't pulse or let fuel through. Sounds like CPS again, doesn't it?

Reply to
spydey

GREAT NEWS!!!!!!!!! Problem solved. You're not going to believe it but it all comes down to wiring. (which I suspected in the first place but thought I had eliminated that). I went back into the harness and started checking wiring. I realized that when I was checking the ground wires inside the wire loom that I missed about a 18 in section just after the main splice on the firewall, engine side. They looked good but decided to investigate further. Upon a more thorough visual inspection I noticed two little pin holes where someone had apparantly probed the wires at one point in time. Remembering that the customer had told me he had submersed the jeep past the windsheild in soupy water at one time I decided to remove the covering on the wires.......They literally fell apart.

So....it all comes down to a bad ground. It was something simple but hidden.

Reply to
spydey

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.