Cadillac Jim Posted July 16, 2006 Report Share Posted July 16, 2006 The "fuel pump failure" that happens to a lot of late 1990's E/K platforms is poor contacts on the connector inside the gas tank. Sometimes it melts. The pump is fine but with the connector ruined, the only thing that they can do is replace the pump. That's a low-mileage thing covered by warranty (it happened to me). High-mileage fuel pump failure is more likely to be other things. But this and any electrical component failure in a high-mileage car is likely to be a wiring or connector problem. Since that is usually simpler, easier an cheapter to fix and easier to trobleshoot, you should look at that first. Besides, looking at the voltages and resistances in the wiring helps you diagnose the electrical device. This is what the factory manuals do in the troubleshooting procedures for the various codes. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Jeff Posted July 17, 2006 Author Report Share Posted July 17, 2006 Thats good to know- I sure hate to buy a pump! Is there anything like a fuel cut-off security thing that may be overriding the pump? You know what I mean? I'm not sure if I'm calling it the right thing or not. Link to comment Share on other sites More sharing options...
Cadillac Jim Posted July 18, 2006 Report Share Posted July 18, 2006 There is nothing that will force the fuel pump on except possbily a fuel pressure sensor that is bad and chronically reads low. There are several things that will force it off. A few that I can name are Engine not turning over. Fuel pressure sensor bad -- reporting high fuel pressure. Rev limiter. Safety fuel-off such as air bag delployment. Others that I didin't think of just now. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
JimD Posted July 18, 2006 Report Share Posted July 18, 2006 There is nothing that will force the fuel pump on except possbily a fuel pressure sensor that is bad and chronically reads low. There are several things that will force it off. A few that I can name are Engine not turning over. Fuel pressure sensor bad -- reporting high fuel pressure. Rev limiter. Safety fuel-off such as air bag delployment. Others that I didin't think of just now. Just for the record: There is no fuel pressure sensor. Rev limiting is accomplished by fuel injector pulse width. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
Jeff Posted July 18, 2006 Author Report Share Posted July 18, 2006 This baby's getting a new pump, I guess. I was told that low fuel pressure would cause the backfiring issue. The backfire can push the valves out of sync and cause the "out of time" sounding cranking. Letting it sit while I put the seal back on the pressure release lets the valves get back into position (hydraulic pressure?) A faulty pump sends the "low" fuel pressure back to the rail and causes another backfire, etc. etc... vicious circle A faulty fuel pump only has so many "last breaths", I guess... and it took it's last one when I took the old battery off. When I put the new battery on and with no fuel in the rail, it spun over like it's supposed to with no backfire and therefore no "out of time" sound. SO... does that sound right? Maybe I don't suuuuck after all! Link to comment Share on other sites More sharing options...
Logan Posted July 19, 2006 Report Share Posted July 19, 2006 If it is the second fuel pump to be installed recently......I would suspect the fuel pump wire harness is damaged. Easy to miss. You need to inspect the upper in-tank plug connector. Look for a blackened/burnt or blued wire teminal. Easy to not know....until you drop a gas tank a couple of times. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
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