Jrwhite3230 Posted September 10, 2013 Share Posted September 10, 2013 I have no power to fuel pump ive checked the pump its good and have followed the harness as far as I could to fuse block from there I have no clue I have checked relay and coil no power there too ,I have no schematic for this vehicle is there anyone who might know of a site to download a (non Haynes) but manufacturers schematics of complete fuel systems electrical diagram? and any suggestion's welcome thanks for your help . jrwhite Link to comment Share on other sites More sharing options...
cruiser54 Posted September 10, 2013 Share Posted September 10, 2013 On the driver's side inner fender is a white ceramic resistor mounted near the air cleaner. Battery voltage goes in one side and a reduced voltage comes out to the fuel pump to reduce noise. If it's bad, no power to fuel pump. Fine to bypass it. Link to comment Share on other sites More sharing options...
mvusse Posted September 10, 2013 Share Posted September 10, 2013 The resistor is bypassed on startup (and under wide open throttle), so it should at least run for a second after turning the key on, and during starting. You say you checked the relay. Did you check to see if the relay is good, or did you check to see if the relay gets power during cranking (or for a second after turning the key on)? No spark is usually a bad CPS. Link to comment Share on other sites More sharing options...
metrictonner Posted September 10, 2013 Share Posted September 10, 2013 fuel pump: A way to check your relays is rotate them one position. They are all the same. Check your battery charge. The starter could be taking all the power from a low charge battery. coil: Your C201 a C202 plug contacts could be old and in need of reforming. Cleaning these things just makes matters worse unless you have access to Electrolube. Link to comment Share on other sites More sharing options...
Jrwhite3230 Posted September 10, 2013 Author Share Posted September 10, 2013 I have checked all the relays and they are good but I'm not getting power to them ,also no spark to coil or power to coil at the coils primary connection, I'm realy needing a schematic that shows entire fuel system electrical including where it connect's to the ecu, which I suspect the problem reside's but without ,correct diagram its difficult to connect the dots Link to comment Share on other sites More sharing options...
87MJTIM Posted September 10, 2013 Share Posted September 10, 2013 What yr? There is the complete wiring diagram for an 88 on the forum somewhere. Other years? IDK. I bought a hard copy for the 87. Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 10, 2013 Share Posted September 10, 2013 What year?? https://skydrive.live.com/?cid=c40904cfda278a46&id=C40904CFDA278A46!115 Link to comment Share on other sites More sharing options...
Jrwhite3230 Posted September 10, 2013 Author Share Posted September 10, 2013 I found the problem and I suspected it all along but was just avoiding the thought band afraid to admit it (its the ecm/electronic control module ) took it out inspected the pins and there was one pin sorta discolored and corroded (due to excessive heat) pin number 4 bottom row of the right connector . I opened up the ecm and located circuite area has been cooking fried chicken, resister looks to be bad, my knowledge of why stop's there (just wore out from normal usage or is there something else causing this problem ? hey guy's I thank you from the help and I'm in debted to you I do still need a good diagram for this truck depending on the Haynes takes you no wheres . jrwhite3230 Link to comment Share on other sites More sharing options...
cruiser54 Posted September 10, 2013 Share Posted September 10, 2013 Grab an eCU from an 89 or 90 with the auto trans from the junkyard and you should be good to go. Link to comment Share on other sites More sharing options...
87MJTIM Posted September 11, 2013 Share Posted September 11, 2013 He still did not say what yr it is. Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 11, 2013 Share Posted September 11, 2013 He still did not say what yr it is. Look at the title. Please guys, edit your profile signature detailing exactly what your ride is. Use the drop-down menu on your username (upper RH corner) -> My Settings -> Signature. You'll get better answers to your questions. Like cpa tim did. :thumbsup: Link to comment Share on other sites More sharing options...
87MJTIM Posted September 11, 2013 Share Posted September 11, 2013 :doh: Sorry 'bout that, Chief. I guess I should RTF header. Link to comment Share on other sites More sharing options...
Jrwhite3230 Posted September 17, 2013 Author Share Posted September 17, 2013 Hey guy's srry for not responding my pc been down for about a week since my last post and my Comanche is an 89 jeep pioneer 2w/dr 4.0 bored 50 over/(not much sleeve left) I replaced ecu,and so far still not getting power ill get back soon ,I'm going to go through the entire system the best way I know (process of elimimation), Link to comment Share on other sites More sharing options...
Jrwhite3230 Posted September 17, 2013 Author Share Posted September 17, 2013 ok I'm still not getting power to relays and also no spark as well Link to comment Share on other sites More sharing options...
carnuck Posted September 17, 2013 Share Posted September 17, 2013 Ground on the block is loose or the ignition switch slider snapped in half inside (just fixed mine) Link to comment Share on other sites More sharing options...
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