Tyson Josh Posted January 12, 2021 Share Posted January 12, 2021 have a comanche 87 , in line 6cylinder 4.0 Battery light comes on when we turn the key on (didn't do that before). It will crank over but doesn't start. The fuel pump does not prime, no power to it. Changed the starter relay and fuel relay. I am stumped. Need help please. Link to comment Share on other sites More sharing options...
Limeyjeeper Posted January 12, 2021 Share Posted January 12, 2021 Could be the CPS. Do you have spark? Link to comment Share on other sites More sharing options...
BeatCJ Posted January 12, 2021 Share Posted January 12, 2021 No power to it when and where? You only get power for 2-3 seconds while priming and while cranking. Have you checked the ballast resistor on the driver side fender? Link to comment Share on other sites More sharing options...
Limeyjeeper Posted January 12, 2021 Share Posted January 12, 2021 Don't think the 87 had the ballast resistor but I might be wrong. If an 87 was fitted with one it was due to a noisy fuel pump TSB or recall. Link to comment Share on other sites More sharing options...
WahooSteeler Posted January 13, 2021 Share Posted January 13, 2021 Have you jumpered the fuel relay circuit and listened closely for the fuel pump? Also, check you fusible links on your starter relay. You said the battery light coming on just started happening, so possibly something is drawing hard on the battery and your fuel pump fusible link burned up. I had a similar problem and discovered the link issue, replaced, fuel pump powered up and no problems since. Link to my thread where Ohm helped me troubleshoot and source the problem. Hope it helps, if anything it may eliminate possible causes. Link to comment Share on other sites More sharing options...
BeatCJ Posted January 13, 2021 Share Posted January 13, 2021 4 hours ago, Limeyjeeper said: Don't think the 87 had the ballast resistor but I might be wrong. If an 87 was fitted with one it was due to a noisy fuel pump TSB or recall. Mine does. Link to comment Share on other sites More sharing options...
87MJTIM Posted January 13, 2021 Share Posted January 13, 2021 13 hours ago, Limeyjeeper said: Don't think the 87 had the ballast resistor but I might be wrong. If an 87 was fitted with one it was due to a noisy fuel pump TSB or recall. There was a TSB to install a ballast resistor. Some 87s got this from the dealers. I have an 87 parts XJ that has one installed. My original 87 MJ has never had one. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted January 13, 2021 Share Posted January 13, 2021 22 hours ago, BeatCJ said: No power to it when and where? You only get power for 2-3 seconds while priming and while cranking. Have you checked the ballast resistor on the driver side fender? Link to comment Share on other sites More sharing options...
cruiser54 Posted January 14, 2021 Share Posted January 14, 2021 What if the ground for the fuel pump behind the left taillight was crappy? CRUISER'S MOSTLY RENIX TIPS IMPROVING THE FUEL PUMP GROUND JANUARY 3, 2016 CRUISER54 51 COMMENTS The fuel pump and fuel tank sending unit ground at a sheet metal screw up behind the spare tire on an XJ, and behind the driver’s taillamp on an MJ. Not only is a sheet metal screw a lousy way to ground things, this ground path is long and travels through some connectors that are prone to corrosion and moisture. Locate the black wire on the HARNESS side of the fuel pump/sender 3 wire connector. Remove a 6″ length of the split loom covering. Strip back about 1/2″ of insulation from the BLACK wire. Take your new ground wire, preferably at least 14 gauge and 12 to 18 inches long as needed, strip it about 3/4″, and wrap it around the exposed part of the harness plug wire.Solder the connection. Tape it up and reinstall the split loom covering. At the other end of your new ground wire, add a crimp on eyelet. Attach the eyelet under a bolt that goes directly into the chassis. Be sure to clean the attaching point til shiny and apply OxGard to the contact surfaces. Link to comment Share on other sites More sharing options...
cruiser54 Posted January 14, 2021 Share Posted January 14, 2021 Also, before I did anything else, I would complete Tips 1 through 5 on my website. Link to comment Share on other sites More sharing options...
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