Back_Country

My '89 Jeep Cherokee has developed a very strange electrical problem I am hoping someone here can help solve:

The vehicle runs great - no problems there. After the vehicle has been driven until it is warmed up and then turned off it will sporadically not start again until it has totally cooled down - sometimes a half hour or an hour. This problem does not have to do with the engine but with the electrical system. When the key is turned all the way to start, the engine starts and will run and rev up with the accelerator as long as the key is in the start position. As soon as the key returns to the run position the car shuts down.

I thought the problem lay in a worn out starter/run switch that is activated by the key which I replaced but still have the same issue. This problem has never occurred when the vehicle is cold, only when the engine is warm making me think that there is a possible electrical connection somewhere else that is being affected by the heat of the engine.

Any help or suggestions on where to look to solve the problem would be much appreciated as the vehicle is currently not reliable and needs to be fixed.

cruiser54

There is a fuel pump ballast resistor on the driver's side fender well that gives the fuel pump 12 volts on starting, and 9 volts in the Run mode. If it's failing because of heat, that could be your issue. You can bypass it for diagnostic purposes or forever if you wanna. Only there to keep the fuel pump noise down.

cruiser54

And since we've got your attention and you own a Renix Jeep, If I were you I would click on the "pink link" in my signature and perform the simple and cheap procedures outlined in Posts # 1, 3, 4, and 7. Enjoy your Renix Jeep.

Back_Country

When I disconnect the Fuel Pump Ballast Resistor I get the same symptoms as when the vehicle is started shortly after being driven. I have bypassed the Resistor with a small jumper wire and will drive it and see if this remedies the problem.

Thanks for the help, I would have never found that resistor without assistance. I will post in a few more days if this has indeed solved the problem or not.

freegdr

Did you adjust the switch after install? What did plug look like to switch ?

cruiser54

Keep us posted. Is your fuel pump noisier than before?

Back_Country

I adjusted the switch when I installed it. The two plugs to the switch were clean.

I don't notice a difference in the fuel pump noise. Never noticed the fuel pump making sound in the past but the vehicle is a little loud from a squeaking A/C compressor.

So far we have not had the no start problem occur again. I have tried to get it to happen with no luck. My daughter drove it a bit yesterday and it still has not reoccurred. Time will tell as it is an intermittent problem.

I will post an update as the vehicle is driven more. Thanks for the help.

cruiser54

Thanks for keeping us in the loop. Mighta been the resistor all along. If there is no bothersome noise, leave it bypassed.