89MJComanche Posted January 26, 2009 Share Posted January 26, 2009 I found another low mileage MJ that is a little bit rusty that I would like to buy because the guy only wants $400 for it. It sprays fuel and the check valve = fuel pump good (was recently replaed) CCS was recently replaced Distributor was recently replaced Still no Spark. Pick Up Coil?? Body Computer on the dash?? Blown Ignition Fuses?? I searched for quite a few strings and the only real good post that I found was the CCS post and that is not it. Any suggestions? Link to comment Share on other sites More sharing options...
jtdesigns Posted January 27, 2009 Share Posted January 27, 2009 buy then fix it... What engine? Link to comment Share on other sites More sharing options...
89MJComanche Posted January 27, 2009 Author Share Posted January 27, 2009 Right.... But I am trying to get it running so that I can drive it home. Link to comment Share on other sites More sharing options...
89MJComanche Posted January 27, 2009 Author Share Posted January 27, 2009 buy then fix it... What engine? I don't believe that the 4cyl had a RENIX IGNITION system?? It was AMC right?? Anyhow this MJ is a 4.0 Link to comment Share on other sites More sharing options...
jtdesigns Posted January 27, 2009 Share Posted January 27, 2009 Go ahead and pay the guy and tow it home to put a CPS in it. Someone chime in on the link he needs that shows where and how to replace it.. CPS= Crankshaft Position Sensor.. Unless thats what your calling the CCS?? here's one link I had Bookmarked,, not the one I'm looking for though.. http://members.cox.net/wilsond/Fixes/diagnostics.html#CPSdetails OK here's the one I was looking for http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm I knew I had it somewhere in the land of bookmarks... Link to comment Share on other sites More sharing options...
89MJComanche Posted January 27, 2009 Author Share Posted January 27, 2009 CCS CPS Same Thing... Crank Case Sensor, Crank Position Sensor. Link to comment Share on other sites More sharing options...
pingpong Posted January 27, 2009 Share Posted January 27, 2009 It could be that or a bad coil. Since the distributor was replaced.. I have to ask why.. they normally don't go bad. Link to comment Share on other sites More sharing options...
jeepcoma Posted January 27, 2009 Share Posted January 27, 2009 It could be that or a bad coil. Since the distributor was replaced.. I have to ask why.. they normally don't go bad. Agreed... when and why was it replaced? Also, how did you verify no spark? Best way is with an induction timing light over the plug wires to check if they're firing while the plus are in the combustion chambers under normal conditions. If you're just assuming no spark because you have fuel and compression, it could just be spark at the wrong time; distributor hold-down bolt loose, causing the dist to slowly walk out of timing until it no longer restarts, distributor installed at TDC of the exhaust stroke, vacuum advance port frozen at full advance... If there's no spark whatsoever, I'd check a few simple things first like the plug wire from the coil to the tower is good and tight, the hot leads to the coil aren't all corroded and are in fact properly connected (I had a problem once where the hot 12+V wire wasn't properly crimped into the terminal, if you went around corners a certain way the wire would break the connection and there'd be no spark until you straightened out and the engine would come back to life). Then there are always computer issues, but I know nothing about the Renix. Link to comment Share on other sites More sharing options...
BLHTAZ Posted January 27, 2009 Share Posted January 27, 2009 The Renix ECU's virtually never fail...and if they do, it's typically a problem in the injector field with the #4 injector. 90% + of the time there is a no spark issue, it is the CPS. Just because it was replaced doesn't meant that it's not still the cause. I have seen them be bad right out of the box before, but because it was replaced, that would make it a little less suspect than something to do with the coil itself, but not out of the question for the cause. Link to comment Share on other sites More sharing options...
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