Comanche won't start - JeepForum.com

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post #1 of 28 Old 06-01-2013, 11:13 PM Thread Starter
Bryce527
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Comanche won't start

Okay so I have an 88 Comanche with the 2.5L engine. The thing will crank but just won't start. I'm having trouble figuring out what the issue is. And to be clear I am very unexperienced with working on cars.

Anyways. I have purchased a brand new battery for it. I have checked what is getting voltage. When it's trying to start there is electricity going from the ignition coil to the distributor but there isn't any coming from the distributor to the spark plugs. One would assume I guess that the distributor has gone bad, and that could be a possibility. As i dont know much about cars What else could be the culprit of this problem? Through research I've found maybe that the crankshaft position sensor has gone bad, or does this have nothing to do with it? What could cause the problem of power not coming from the distributor? If the distributor has not been properly installed would this problem happen? Or is the problem something that I have not mentioned?

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post #2 of 28 Old 06-02-2013, 12:48 PM
Speedymcracer01
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Can you explain a little more of what you have done or checked this will make it just a little bit easier to diagnose the problems....or is your first post on this thread all you have done to it?
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post #3 of 28 Old 06-02-2013, 07:53 PM Thread Starter
Bryce527
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I apologize for a not very descriptive explanation. I have checked that there is 12volts coming from the coil to the center of the distributor but when cranked no spark is going to the distributor. Nor is there anything coming out of the distributor. I'm really not good with cars and apologize for my ignorance. I don't have much knowledge to know what could be cause of it not starting.
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post #4 of 28 Old 06-02-2013, 08:18 PM
Speedymcracer01
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Quote:
Originally Posted by Bryce527 View Post
I apologize for a not very descriptive explanation. I have checked that there is 12volts coming from the coil to the center of the distributor but when cranked no spark is going to the distributor. Nor is there anything coming out of the distributor. I'm really not good with cars and apologize for my ignorance. I don't have much knowledge to know what could be cause of it not starting.
Sounds like you need to pull your distributor cap and check the inside for wear.i would also check the distributor the gears on the bottom could be worn have you looked to see if the rotary button inside the distributor is rotating like it should?
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post #5 of 28 Old 06-02-2013, 09:00 PM Thread Starter
Bryce527
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I have looked inside the distributor cap and there's a possibility that it could wore down. Tomorrow I plan to go a head a get a cap and rotor and see if that fixes it. There are fairly cheap parts. The rotor is rotating when I crank the engine
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post #6 of 28 Old 06-03-2013, 02:23 AM
Speedymcracer01
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Alright well the distributor and rotor would be a good and cheap place to start keep me posted
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post #7 of 28 Old 06-05-2013, 08:54 AM Thread Starter
Bryce527
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I replace the cap and rotor. And also the ignition control module. Still no spark at the distributor center. What else could it be?
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post #8 of 28 Old 06-05-2013, 02:40 PM
cruiser54
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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 isnít 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 wonít 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!! Thatís 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. Itís 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 3/8Ē from the stock 5/16Ē, 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
Attached Thumbnails
CPS wire routing.jpg  

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
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post #9 of 28 Old 06-05-2013, 05:08 PM
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Moved to Comanche Tech Forum.
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post #10 of 28 Old 06-06-2013, 09:53 AM Thread Starter
Bryce527
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Okay replaced the crankshaft position sensor. Still not starting. I'm guessing it is some electrical or computer problem? What else could it be?
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post #11 of 28 Old 06-06-2013, 01:46 PM
cruiser54
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You need to start TESTING stuff with a meter. There's lots of things it could be.

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
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post #12 of 28 Old 06-06-2013, 02:55 PM Thread Starter
Bryce527
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Okay
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post #13 of 28 Old 06-06-2013, 02:59 PM
cruiser54
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Quote:
Originally Posted by Bryce527 View Post
Okay
Test the CPS, and make sure you don't see another CPS plug around the same area.

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
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post #14 of 28 Old 06-06-2013, 03:02 PM Thread Starter
Bryce527
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Im going to do a lot of testing this weekend to try and pin point what it is. Ill test the CPS like in the above post. But What do you mean another CPS plug ?
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post #15 of 28 Old 06-06-2013, 03:07 PM
cruiser54
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There was a service bulletin to run a new harness right to the ECU for the cPS. After it was done, the tech was to cut off the old plug. They didn't always do it and so guys have replaced their cPS and plugged it into the dead harness plug which should have been snipped off. A bit of a long shot, but worth the 30 seconds to have a gander.

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
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