comanche32 Posted August 23, 2012 Share Posted August 23, 2012 ok guys I'm lost i have a 90 comanche 4.0 renix auto. ive had a dieing issue for along time its very sperratic and doesnt do it all the to time. it will die most the time after ive drove for a good distance. when it dies it will just crank and not try to start. I have to turn the key off for a few seconds then pump the gas and keep cranking and it will start. it may do it 1 time a week or 5 times just never no. ive replaced plugs wires IAC TPS looked for vaccum leaks I'm just at a complete loss. other times when it dies its right after you start it after sitting awhile but it will start right back up and when it starts it will idle kinda high for a sec then idle down. thanks in advance Link to comment Share on other sites More sharing options...
cruiser54 Posted August 23, 2012 Share Posted August 23, 2012 Got a multimeter and know how to use it? Link to comment Share on other sites More sharing options...
ComancheKid45 Posted August 24, 2012 Share Posted August 24, 2012 sounds like the symptoms of the classic Crank Sensor ;) Link to comment Share on other sites More sharing options...
comanche32 Posted August 24, 2012 Author Share Posted August 24, 2012 yes I have a multimeter and yes I know how to use it Link to comment Share on other sites More sharing options...
cruiser54 Posted August 24, 2012 Share Posted August 24, 2012 Did you adjust that new TPS that you installed? Test your CPS using the following. Better if you could do it when it's hot/failing, but even if done when it's running will tell us something. 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 isn’t 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 won’t 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!! That’s 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. It’s 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, 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 07-30-2012 Link to comment Share on other sites More sharing options...
comanche32 Posted August 26, 2012 Author Share Posted August 26, 2012 thanks for the advice I will definately try that Link to comment Share on other sites More sharing options...
comanche32 Posted August 26, 2012 Author Share Posted August 26, 2012 just tested the cps it was reading between .2and.3 volts. that was not hot that was sitting overnight I will test again after driving today. Link to comment Share on other sites More sharing options...
cruiser54 Posted August 26, 2012 Share Posted August 26, 2012 just tested the cps it was reading between .2and.3 volts. that was not hot that was sitting overnight I will test again after driving today. That's REAL borderline. I would replace it and drill the one mounting hole closest to the top of the engine out so it will sit closer to the flexplate/flywheel. Is your truck an auto or stick? Link to comment Share on other sites More sharing options...
comanche32 Posted August 26, 2012 Author Share Posted August 26, 2012 truck is auto drove it around 40 miles earlier and it only died once. but started right back up. I just tested it again right after i got home it still tested between .2 and.3 Link to comment Share on other sites More sharing options...
cruiser54 Posted August 26, 2012 Share Posted August 26, 2012 truck is auto drove it around 40 miles earlier and it only died once. but started right back up. I just tested it again right after i got home it still tested between .2 and.3 I'd replace the cPS with a high quality one from NAPA or dealer. Drill out the upper hole a bit as suggested above. Link to comment Share on other sites More sharing options...
comanche32 Posted August 27, 2012 Author Share Posted August 27, 2012 ok il try it thanks in advance Link to comment Share on other sites More sharing options...
mountainman Posted August 27, 2012 Share Posted August 27, 2012 Is the test and readings the same for a non renix? Or ? Link to comment Share on other sites More sharing options...
cruiser54 Posted August 27, 2012 Share Posted August 27, 2012 I don't think so. Link to comment Share on other sites More sharing options...
comanche32 Posted August 29, 2012 Author Share Posted August 29, 2012 well I replaced the cps and am getting the same amount of volts .3 and I got the cps from napa Link to comment Share on other sites More sharing options...
cruiser54 Posted August 29, 2012 Share Posted August 29, 2012 well I replaced the cps and am getting the same amount of volts .3 and I got the cps from napa Read the last paragraph in my CPS write-up. Link to comment Share on other sites More sharing options...
comanche32 Posted August 29, 2012 Author Share Posted August 29, 2012 are you drilling the mounting hole in the cps bracket. I just figured a new cps would read higher then my old cps. I'm not really fully understanding what your drilling. thank you for the help Link to comment Share on other sites More sharing options...
cruiser54 Posted August 29, 2012 Share Posted August 29, 2012 are you drilling the mounting hole in the cps bracket. I just figured a new cps would read higher then my old cps. I'm not really fully understanding what your drilling. thank you for the help A little trick for increasing the output of your CPS is to drill out the upper mounting hole, 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. Link to comment Share on other sites More sharing options...
comanche32 Posted August 30, 2012 Author Share Posted August 30, 2012 well drove the truck after i put the new cps in and now its running very rough like its missing. it didnt run this rough before i put the new cps in. did I get a bad cps or something else now. Link to comment Share on other sites More sharing options...
cruiser54 Posted August 30, 2012 Share Posted August 30, 2012 Did you bump the hose from the throttle body to the MAP sensor in the process? CPS generally doesn't cause running problems. Only crank no starts and dying. Link to comment Share on other sites More sharing options...
comanche32 Posted August 30, 2012 Author Share Posted August 30, 2012 found it unplugged a fuel injector hopefully the new cps will cure the dieing problem been battiling this issue for a year now. thanks for the help Link to comment Share on other sites More sharing options...
1989 Eliminator Posted September 7, 2012 Share Posted September 7, 2012 I read the CPS write-up but I still have a question on the CPS adjustment... the CPS form says to drill out the top mounting hole in the actual CPS and then push down on it while tightening it onto the bell housing. I'm not seeing how making the hole diameter bigger would make the CPS come closer to the flywheel. :dunno: I can see making the width of the bracket smaller would make sense for it to be set-in lower. Link to comment Share on other sites More sharing options...
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