1986 comanche starting problem - JeepForum.com

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post #1 of 4 Old 11-26-2012, 10:47 AM Thread Starter
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1986 MJ Comanche 
Join Date: Nov 2012
Location: Kingston
Posts: 2
1986 comanche starting problem

It starting taking longer to start truck, so I installed new plugs, wires, ditributer and rotor....now it turns over and sometimes starts just for a second. From what I have read, I removed the Crankshaft positioning sensor and cleaned all the grease from the sensor re-installed but no luck. My question is..should I buy a new CPS or is there another trick I should try?
Thanks in advance

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post #2 of 4 Old 11-26-2012, 02:48 PM
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1990 MJ Comanche 
Join Date: Jul 2011
Location: woodbury
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Before you read below, do you have a 4.0?

Check your fuel pressure at the rail. If it starts but only runs for a moment its not getting fuel and is probably a bad ballast resistor and/or fuel pump. When you turn your key to run you should hear the fuel pump kick on for a moment or two then kick off. You might have to open your door to hear it. If you dont hear it then its very possible you have a bad fuel pump/ballast resistor.
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post #3 of 4 Old 11-26-2012, 03:38 PM Thread Starter
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1986 MJ Comanche 
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Location: Kingston
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It is a 2.5 litre 4WD
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post #4 of 4 Old 11-26-2012, 07:18 PM
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1990 MJ Comanche 
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Location: Prescott
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With it started, spray throttle body cleaner around where the intake manifold meets the head and around the throttle body where that pesky vacuum block is with the 4 fittings.

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

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