Iv8everyThing Posted April 19, 2008 Share Posted April 19, 2008 Hi I have a 88 Jeep comanche with a 2.5, auto and I just replaced the valve cover after I saw it was cracked. Now I went to start it and nothing. I has no spark, but has power going to the Ignition module. I had the coil checked and it's good. I really want to try to get this running before Monday. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted April 19, 2008 Share Posted April 19, 2008 Hi I have a 88 Jeep comanche with a 2.5, auto and I just replaced the valve cover after I saw it was cracked. Now I went to start it and nothing. I has no spark, but has power going to the Ignition module. I had the coil checked and it's good. I really want to try to get this running before Monday. everything connected? did you get oil in/on the cap/rotor? how're the spark plugs? Link to comment Share on other sites More sharing options...
Iv8everyThing Posted April 19, 2008 Author Share Posted April 19, 2008 No oil got on any of that, everything is hooked up as it was before I messed with the cover, and spark plugs are new. I don't even have spark from the coil directly. I wondering if the module is bad. When I first got the truck. and did the plugs, cap, rotor, wires it did want to start right away so I waited like an hour then it started. Ever since then till now it started fine. Link to comment Share on other sites More sharing options...
Iv8everyThing Posted April 20, 2008 Author Share Posted April 20, 2008 No one else has any ideas? Link to comment Share on other sites More sharing options...
Wildman Posted April 20, 2008 Share Posted April 20, 2008 I really don't know the 2.5 engine. But you had to knock something off while you were changing the valve cover, I'd hate to say this, but you just need to re-trace your steps and see if some thing came off while you were working on it. If the coil is good, check if you have spark at one of the plugs, that would tell you if there's a problem with the distributor cap, or the wires (I'm thinking coil wire) Are you getting fuel??? Check that. Link to comment Share on other sites More sharing options...
Iv8everyThing Posted April 20, 2008 Author Share Posted April 20, 2008 Everything was hooked up like it was before I took the cover off. I was thinking either the ignition module or even the CPS is bad. How would I test these to see if they are bad? Also I checked for spark at the plug and off the coil and nothing. I even put alittle fuel down the throttle body and nothing so its spark either a bad module I was thinking or its not getting a signal to tell it to fire. Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 20, 2008 Share Posted April 20, 2008 Everything was hooked up like it was before I took the cover off. I was thinking either the ignition module or even the CPS is bad. How would I test these to see if they are bad? Also I checked for spark at the plug and off the coil and nothing. I even put alittle fuel down the throttle body and nothing so its spark either a bad module I was thinking or its not getting a signal to tell it to fire. Check for 12V on the coil primary. Link to comment Share on other sites More sharing options...
Eagle Posted April 20, 2008 Share Posted April 20, 2008 Always look for the obvious. Coils and ignition modules do go bad ... but very rarely, and virtually never right on cue after you did work unrelated to them. So I suggest you stop looking in that direction and be open to the very real probability that, regardless of what you THINK you didn't mess with -- somewhere in the process of changing the valve cover you disconnected something related to the spark. My guess is the CPS. The wire runs right behind the back of the head and valve cover. There's supposed to be a clip back there -- I don't know if that clip is attached to a valve cover bolt on the 2.5L. Are you certain you didn't disturb the CPS wire or connector? Keep in mind that you may not have had to unplug it -- it runs near the exhaust manifold, and if your wire was even damaged, it could have worked but then jostling it when you changed the valve cover might have shorted it out. There is a way to test the CPS with a multi-meter. Somebody posted a link awhile back to an article by a guy with screen name Jabba the Hut who posted a description of how to test all the sensors in the Renix system. See if you can find that article. Does anyone have it book-marked? Link to comment Share on other sites More sharing options...
maddzz1 Posted April 20, 2008 Share Posted April 20, 2008 Here you go: http://www.lunghd.com/Tech_Articles/Eng ... ostics.htm Link to comment Share on other sites More sharing options...
Iv8everyThing Posted April 20, 2008 Author Share Posted April 20, 2008 Here you go: http://www.lunghd.com/Tech_Articles/Eng ... ostics.htm This is for a 4.0 is it the same as 2.5? Link to comment Share on other sites More sharing options...
Eagle Posted April 21, 2008 Share Posted April 21, 2008 Here you go: http://www.lunghd.com/Tech_Articles/Eng ... ostics.htm This is for a 4.0 is it the same as 2.5? For 1988, yes. Your TBI is still a Renix system, same as the 4.0L. Most of the sensors are the same. I know the CPS is the same part number. Link to comment Share on other sites More sharing options...
carnuck Posted April 26, 2008 Share Posted April 26, 2008 You probably accidentally unplugged the CPS on the driver's side. Link to comment Share on other sites More sharing options...
georgiaboy27 Posted April 26, 2008 Share Posted April 26, 2008 yup.....CPS, maybe not sending signal back to coil...maybe Link to comment Share on other sites More sharing options...
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