Questions and Answers

Jeep Cherokee No Start, Hard Restart

Q. I have a 1990 Jeep Cherokee, 4.0 liter engine, automatic transmission, 139,000 miles, fuel injected, A/C and cruise control. I have had numerous trouble with this vehicle stalling after it warms up. I have replaced the fuel pump, fuel pump relay, fuel filter and Ignition Control Module (ICM) a year ago and again a month ago.

The engine was running fine until it reached operating temperature then would shut down. If you let it sit for five minutes it would start up and run fine for the rest of the day. A mechanic went to test the computer and said he was unable to because it didn't have the right plug. He thought it might be a Canadian plug or something.

He advised us to change the ICM again as it sounded like it was the culprit. We changed it a month ago and it ran fine for about two weeks and now it stalls one or twice a day every four or five days. Could it be the ICM again or something related to it? If the module is going out this often what could be causing it?

One day while we were broke down on the side of the road a man stopped to check on us and he was a Jeep owner. He said Jeep stood for "Just Empty Every Pocket". I'm beginning to feel he may be right.

Thanks,
Rick

A. Some 1989 and early 1990 vehicles equipped with the 4.0 liter engine and automatic transmission may experience an engine no-start, hard restart, or an engine die-out. This condition may be caused by low signal strength from the Crankshaft Position Sensors (CPS) due to a larger than desired distance to the flywheel sensing ring.

What you need to do is check to see if the vehicle has a slotted crank position sensor. If the vehicle is equipped with a slotted crank position sensor, Figure 1, check to see if the CPS grommet on the top of the transmission bell housing has been updated,see Figure 2. If the CPS grommet has not been updated, replace the CPS grommet.

You'll need a Crankshaft Position Sensor, slotted, part number 83100067 and Crankshaft Position Sensors Grommet, dust cover, part number 83100068. When you install it, make certain that the CPS is completely bottomed on the machined lip of the bellhousing and is as close as possible to the flywheel sensing ring without contacting it.