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View Full Version : 5.9 Cummins Fuel Relay Question



ucdavis
09-11-2005, 09:03
Helping a comrade w/his "starts, then quits, won't run" '98 Cummins ISB (5.9).
Lift Pump runs for ~5 secs then loses 12V signal. I'm assuming there is a relay, either single electrical, or dual like our 6.5's (e-relay @ start, then ECU-switch to OPS for 12V to LP).
Anybody know the schematic enough to coach?
Thanks, Davis

surfbeetle
09-23-2005, 22:21
The lift pumps on those were mounted as pullers, not pushers as the pumps themselves were designed to be. They have a known high failure rate. Dodge has an in tank retrofit pusher kit or you can get a FASS system. What typically happens is the lift pump will fail but the VP44 injection pump will continue to run the truck until it gets damaged and then like our DS4 pumps on the 6.5s, it will crap out. Its around $2,000 to replace at a dealer. Often times, the 24v cummins owners will install a fuel pressure guage between the lift pump and the Injection pump so that they will know when the guage fails. Check out www.tdr1.com (http://www.tdr1.com) for dodge cummins info.