No spark need help?! -
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post #1 of 2 Old 08-13-2012, 06:00 PM Thread Starter
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Join Date: Sep 2005
Location: Mount Pleasant
Posts: 342
No spark need help?!

First problem is I let the jeep sit for about 4 years in the middle of a project which was replacing the steering column and converting to a floor shift. Finally finished replacing the steering column and converting to the floor shift. Problem is now I'm having issues with no spark and not sure where the issue is coming from. I was wondering if anyone knew of this issue being caused from the new steering column. I've already replaced the crankshaft position sensor, checked and the distributor and cap look to be in good condition, and checked the ignition coil with a test light and got a response. Not really sure what else to check out any advice would be great.

Thanks in advance, Brock

88 comanche
5.5" rubicon express
35"x12.5" bfg mt's
d35 in the rear w/ detroit tru track and 4.10 gears

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post #2 of 2 Old 08-14-2012, 06:06 AM
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1990 MJ Comanche 
Join Date: Oct 2009
Location: Prescott
Posts: 11,535
Test the cPS even though it's new.

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
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