McCaffrey

Let me clarify. My 1989 6-cyl, auto never over heats on the water temp. Mid summer running in the mountains and it goes to 200-210 max but normally runs much lower. In fact it runs and starts great. The problem sometimes happens when driving offroad very slow and for extended periods and the indicated engine temp is quite cool. I think something under the hood besides the engine is getting too hot. Almost ever tune-up part has been changed except the CPS. I already have a new one, but before I dive in I was wondering if this might be a good suspect. Or something else?

cruiser54

Since you have a Renix era Jeep, I suggest you TEST the CPS using the procedure below.

And, you should perform Tips 1,3,4, and 5 in the "pink link" in my signature.

Renix CPS Testing and Adjusting



Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.

Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.

The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.

Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.

You should get a reading of .5 AC volts.

If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.

Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.

A little trick for increasing the output of your CPS is to drill out the upper mounting hole to 3/8” from the stock 5/16”, or slot it so the CPS bracket rests on the bell housing when pushed down. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.




Revised 01-26-2013

McCaffrey

Thanks!