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Unread 07-23-2012, 06:11 PM   #1
jklinger
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1989 MJ Comanche 
 
Join Date: Jul 2012
Location: Collegedale, TN
Posts: 1
my 89 Broke Down MJ - At my wits end!

My 2.5 motor was running too rich, then it gradually started not starting while warm... eventually it started stalling, and after a while completely stalled and would no longer start at all.
Replaced Fuel Injector, checked all fuel lines.
Then I determined that it jumped time, because on number 1 compression stroke the rotor was not pointing at number 1.
So I Replaced timing gear and chain. Read Chilton manual on how to setup timing, checked to see that there were indeed 20 pins from timing mark to timing mark. Lined it Up on number 1 compression stroke. Per the manual, I set oil pump shaft at 3 oclock, turned the rotor to 5 oclock to drop it in, and once it was seated it was at 6 oclock. Checked all electric wiring, no bare wires or bad fuses. Have not replaced rotor and cap, but it was running before it jumped time. Have spark, have plenty of fuel. Motor will not fire at all.

This vehicle has the only distributor I've ever seen without electronic components of any kind - no magnetic pickups, etc. Only thing inside is the the rotor. Very odd.

Any ideas appreciated, first time in 20+ years a vehicle has stumped me like this!


Last edited by jklinger; 07-23-2012 at 06:32 PM..
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Unread 08-11-2012, 07:53 PM   #2
87manche17
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1987 MJ Comanche 
 
Join Date: Jul 2012
Location: Harlan, Kentucky
Posts: 168
Ive heard of problems like this, and everyone says its a bad crankshaft positioning sensor witch is located on the driverside of the bellhousing, replace that and see what happens.
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Unread 08-16-2012, 06:36 AM   #3
cruiser54
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1990 MJ Comanche 
 
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Location: Prescott, Arizona
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If CPS was bad, you'd have no spark or fuel.
How good is the spark? What color is it?
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Unread 08-20-2012, 09:03 PM   #4
greaseslapper
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1987 MJ Comanche 
 
Join Date: Feb 2012
Location: worthington, IN
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fuel, spark and timing. Three things it must have to start. you said that it has spark and fuel, BOOM check the timing again and YES the CPS can cause the timing to be off even if there is fuel and spark. if timeing is right then its the CPS. the distributer it N/A so the timeing adjust comes form the CPS.
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2.5 four wheel drive.
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Unread 09-16-2012, 01:43 AM   #5
dkroll
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1989 MJ Comanche 
 
Join Date: May 2008
Location: Independence, Missouri
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What did you find?
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Unread 09-16-2012, 07:35 AM   #6
cruiser54
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1990 MJ Comanche 
 
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Quote:
Originally Posted by greaseslapper View Post
fuel, spark and timing. Three things it must have to start. you said that it has spark and fuel, BOOM check the timing again and YES the CPS can cause the timing to be off even if there is fuel and spark. if timeing is right then its the CPS. the distributer it N/A so the timeing adjust comes form the CPS.
The ECU controls the timing, not the CPS. As a matter of fact you can move the CPS one way or the other to trick the ECU as to where TDC is and it will run just dandy. If you have spark, it is NOT the CPS.
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comanche , distributor , rotor , timing , timing chain replacement
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