no spark no fuel

1989 MJ 4.0L BA10/5


my friend has a 1989 MJ that is not getting any spark (not even from the coil itself) nor is it getting fuel. we currently have done the following changed the CPS changed the Coil had the ICM tested at autozone which tested fine jumped the connection for the fuel/ignition relay under the hood which got the fuel pump to kick on and stay on, we changed out the ballast resistor, we checked every connection we could possibly think of cleaned them out nicely then put some dielectric grease in them, we cleaned up the battery terminals and the connectors. we are starting to run out of ideas the last thing we can think of is the ECU. any and all suggestions are greatly apperciated.

Check the CPS with a meter before proceeding. They're known to be bad right out of the box, especially from Autozone.

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, 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 07-30-2012

cruiser54 said:

Check the CPS with a meter before proceeding. They're known to be bad right out of the box, especially from Autozone.

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, 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 07-30-2012

Click to expand...

thanks we will check that next we put in another ECU which did fix the fuel pump problem but we still arent getting any spark we also changed the ballast resistor

Hate to tell you but the ballast resistor is there to reduce voltage to the fuel pump to quiet it down. Has nothing to do with ignition.

turned out to be the Distributor

Can't understand how the distributor would cause no fuel..........

cruiser54 said:

Can't understand how the distributor would cause no fuel..........

Click to expand...

well the new ECU fixed the no fuel issue and the new distributor fixed the no spark issue

995speed said:

well the new ECU fixed the no fuel issue and the new distributor fixed the no spark issue

Click to expand...

Oh, the REST of the story..............