90 renix long crank did the basics already??
Thread Starter
CF Veteran
Joined: Feb 2011
Posts: 3,074
Likes: 0
From: Bergen County, New Jersey U.S.A.
Year: 1990 Laredo
Model: Cherokee
Engine: 4.0 Inline 6 Renix
Rooster, have you ever checked the AC voltage output of your CPS? .5 or better while unplugged and cranking.
Did you follow my write-up when doing the grounds, and possibly add a couple?
Your sync generator or stator as it's called also, inside the dizzy could be bad as Flintstone mentions. Even if he calls it by the wrong name just to irritate me.
Did you follow my write-up when doing the grounds, and possibly add a couple?
Your sync generator or stator as it's called also, inside the dizzy could be bad as Flintstone mentions. Even if he calls it by the wrong name just to irritate me.
Senior Member
Joined: Nov 2009
Posts: 504
Likes: 3
From: Forest Grove, OR
Year: 1989
Model: Cherokee
Engine: Inline 6, 4.ol
I was told by my old auto tech teacher that was a jeep tech for like 40 years, that the renix system has to get a reading from every cylinder and that it has to crank over at least 6 times before it can start. Which is exactly what mine does, i have counted. Every time 6 cranks and it starts.
Thread Starter
CF Veteran
Joined: Feb 2011
Posts: 3,074
Likes: 0
From: Bergen County, New Jersey U.S.A.
Year: 1990 Laredo
Model: Cherokee
Engine: 4.0 Inline 6 Renix
I was told by my old auto tech teacher that was a jeep tech for like 40 years, that the renix system has to get a reading from every cylinder and that it has to crank over at least 6 times before it can start. Which is exactly what mine does, i have counted. Every time 6 cranks and it starts.
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Renix CPS Testing and Adjusting (I think He meant CKP sensor). 
Again thanks to Cruiser;
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 it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.

Again thanks to Cruiser;
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 it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.
Thread
Thread Starter
Forum
Replies
Last Post
Jared Hall
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
2
Sep 7, 2015 08:56 AM
shotseven
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
0
Sep 6, 2015 03:06 PM
jmarzo
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
3
Sep 2, 2015 08:29 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)




