cruiser54 Posted May 3, 2016 Share Posted May 3, 2016 I bet I know what the problem is. Happened on my wife's xJ. When the fuel level gets high, it sloshes against the ground wire from the fuel pump to the mounting plate of the fuel sender. The ground wire goes all intermittent and quits grounding the fuel pump. The photo shows the ground wire all melted on the XJ. Link to comment Share on other sites More sharing options...
DirtyComanche Posted May 3, 2016 Share Posted May 3, 2016 Well, that's a reassuring thing to find. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 3, 2016 Share Posted May 3, 2016 I bet I know what the problem is. Happened on my wife's xJ. When the fuel level gets high, it sloshes against the ground wire from the fuel pump to the mounting plate of the fuel sender. The ground wire goes all intermittent and quits grounding the fuel pump. The photo shows the ground wire all melted on the XJ. Probably caused from long term ethanol rot. Link to comment Share on other sites More sharing options...
cruiser54 Posted May 3, 2016 Share Posted May 3, 2016 I bet I know what the problem is. Happened on my wife's xJ. When the fuel level gets high, it sloshes against the ground wire from the fuel pump to the mounting plate of the fuel sender. The ground wire goes all intermittent and quits grounding the fuel pump. The photo shows the ground wire all melted on the XJ. Probably caused from long term ethanol rot. I don't think so. The terminal at the fuel pump flange was burned looking and wasn't tight. Definitely a thermal issue. Ran great as long as fuel wasn't sloshing against the wire. All this said, no better time to perform the fuel pump ground wire upgrade in the link below: http://cruiser54.com/?p=249 Link to comment Share on other sites More sharing options...
Mikethe80sFanatic Posted May 3, 2016 Author Share Posted May 3, 2016 Ok, Makes sense except for one thing. Why would it also be loosing spark as well? Does the ECM kill the spark when it reads intermittent/no voltage from the pump? Link to comment Share on other sites More sharing options...
cruiser54 Posted May 3, 2016 Share Posted May 3, 2016 Ok, Makes sense except for one thing. Why would it also be loosing spark as well? Does the ECM kill the spark when it reads intermittent/no voltage from the pump? No. You may have more than one issue. The ECM is also clueless as to whether you just filled the tank. Link to comment Share on other sites More sharing options...
Mikethe80sFanatic Posted May 3, 2016 Author Share Posted May 3, 2016 Ok, Makes sense except for one thing. Why would it also be loosing spark as well? Does the ECM kill the spark when it reads intermittent/no voltage from the pump? No. You may have more than one issue. The ECM is also clueless as to whether you just filled the tank. I figured the ECM was clueless of the fuel level. I'm asking if the ECM recognizes voltage or a lack of voltage from the fuel pump. I could believe there may be more than one issue. But it has not lost spark at any other point except for these 3 times. Link to comment Share on other sites More sharing options...
Mikethe80sFanatic Posted June 28, 2016 Author Share Posted June 28, 2016 Got a little update on my Comanche. It's been running "Ok" since the last post. Not running perfect, But hasn't left us stranded or thought it would. Until this past weekend. Big local Car Cruise near our home was over the weekend. My fiance was going to take it up to our car club's spot( I was at work). But it just cranked and wouldnt start. A friend came by and put some gas in it, and it started up. So she drove it up to our spot. I get there about an hour or so after. And hop in it to go drive in the cruise, Again it just cranked. So I started checking around. Fuel pump: Didn't hear it priming. Checked for spark: None. And finally, It hit me... I never checked the CPS other than a "Visual" inspection...its there and plugged in. Even after hours of looking through this forum and others. And Cruiser's Renix tips for an answer that was obvious lol. So I unplugged it and plugged it back in. And she fired up. Drove it home, And checked it with my volt meter. Of course, Averaged less than .29V AC. Picked up a new one from Napa and now she's running great. I'll try an post pics of the old CPS...Because my visual inspection wasn't good lol. This was a lesson learned for sure. Link to comment Share on other sites More sharing options...
DirtyComanche Posted June 28, 2016 Share Posted June 28, 2016 Redacted. Link to comment Share on other sites More sharing options...
cruiser54 Posted June 29, 2016 Share Posted June 29, 2016 Did you check the output of the new CPS? Did you modify the new CPS to generate higher voltage? Link to comment Share on other sites More sharing options...
Mikethe80sFanatic Posted June 29, 2016 Author Share Posted June 29, 2016 Output of the new one is roughly .4v AC. Are you asking about the Advance Mod or drilling out the mounting holes? I have not done either. Link to comment Share on other sites More sharing options...
cruiser54 Posted June 29, 2016 Share Posted June 29, 2016 Output of the new one is roughly .4v AC. Are you asking about the Advance Mod or drilling out the mounting holes? I have not done either. drilling. Link to comment Share on other sites More sharing options...
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