Help! Renix no start!
Senior Member

Joined: Jul 2011
Posts: 560
Likes: 25
From: West Covina, Ca.
Year: 1988
Model: Cherokee
Engine: 4.0
Note from DJ
DF you have a good memory see post #7 by cygnus58 in this thread
http://www.naxja.org/forum/showthread.php?t=921802
DF you have a good memory see post #7 by cygnus58 in this thread
http://www.naxja.org/forum/showthread.php?t=921802
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
If his .82 cm figure is correct, that's a fat 5/16". I've changed a few but never realized the thing is a mile from the ring. I gather it's a Hall effect transducer. Gotta wonder what voltage spikes it would make at 1/8 inch.
Might be safer to have gap for crud though.
Might be safer to have gap for crud though.
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Whoops! I stand corrected. After seeing Cruisers pic in post #71 I figured CM.....Maybe, (or maybe not), I'll take a shot at measuring it next time I'm there. Maybe put some bread dough on one, install, remove it, and measure.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
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
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
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
10-4 on that. If you can't hardly see or reach it, how the heck can you figure your gap that's hidden even deeper.
You are positive it's not your meter Mat? All this yack about the gap seems misdirected. The Correct thing, in the Right place, (with the Right bolts/screws), will provide a signal to the ECU that should work. Always has for me. .3> .35+ seems to be a minimum.
You are positive it's not your meter Mat? All this yack about the gap seems misdirected. The Correct thing, in the Right place, (with the Right bolts/screws), will provide a signal to the ECU that should work. Always has for me. .3> .35+ seems to be a minimum.
Thread Starter
Seasoned Member
Joined: Jul 2012
Posts: 312
Likes: 0
From: Little Elm, TX
Year: 1987
Model: Cherokee
Engine: Inline 6 cylinder
I'm positive it's not my meter. I went and bought a brand new "professional" meter. This is the third one I've used. They can't all be bad.


