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jestal · 07-20-2017, 08:57 PM

Generator suddenly developed an "issue".....run 20 minutes and die of fuel starvation. Many reports of this sort of thing happening with the Onan generators so it seems they have a "bad" run of electric lift pumps in the field.

Replaced the pump at Spartan since it was inop and had a 12 volt signal at the pump connections so must be the pump!!... Generator ran for 20 minutes, stalled and would not restart. Must be something else so "take it to Onan".... Cummins-Bridgeway in Grand Rapids immediately diagnosed it as a bad fuel pump (even though it was brand new......bad new parts do happen) I offered up my Amazon purchased spare pump I keep on board for emergencies. Guess what....ANOTHER BAD PUMP. By now even the techs are catching on that something else is wrong. Long story short: the fuel pump is supplied power by the little ECM or electronic controller on the generator itself. The pin for the fuel pump power had loosened and backed out of the connector body and was making intermittant contact. Enough to show 12 volts on a VOM but not enough current to run the motor.

If you suspect a failed generator pump motor I would first supply my own independent 12 volts to the pump from a battery booster box or extra battery. May not be a bad pump but it will certainly prove if the pump is at fault.

The whole issue is exacerbated by the fact that there are a suspect batch of electric pumps out in the field and some in service. Cummins-Bridgeway was replacing fuel pumps in brand new gen-sets before even delivering them. So it might be a bad pump after all........but 3 in row was a bit hard to swallow.

Thanks to the guys at GrandRapids Cummins-Bridgeway for squeezing us in on a tight schedule. They went out of their way to get the repair diagnosed and completed.

MRUSA14 · 07-20-2017, 09:08 PM

Wow, tough problem. Thanks for posting the sucessful outcome.

RubiconTrail · 07-21-2017, 01:59 AM

Al, is this the plug located by the radiator that had the pin problem or another plug?

Thanks!

jestal · 07-21-2017, 12:40 PM

No, the controller is under the side covers. If the left side cover is off it is fairly easy to jiggle the fuel pump positive feed wire and follow it to the controller.

Per the earlier post about changing the gen fuel pump it is harder in an Entegra as the little plate covering the pump is blocked by the hardware of the generator carriage when the generator is fully out. If you hold the lock pin and slide the generator in about 6 inches the plate is clear of obstructions and you can litterally sit under the coach and the pump is accessible. The coach needs to be lifted about 6 inches with the front jacks or front wheels driven onto some planking to get a little extra height. The Tech had a stack of 3 2x12 lumber like gary mentioned earlier to drive the front tires onto.

tqqest · 07-21-2017, 12:58 PM

Hi Jestal,

I am having this same issue with random shut down with my Tiffin AB 45LP with the 10K generator. New fuel pump, and it still shuts down within minutes or several hours. Added an external power supply direct to the fuel pump and it never shuts down. When you say left side, do you mean the driver or passenger side? I know the main control board is up front, and there is a fuel pump relay up there also. Is there another controller? Unfortunately I have to pull the whole generator on mine to get to the fuel pump cover on the drivers side.

jestal · 07-21-2017, 08:04 PM

Left side as in drivers side. Have you tried getting to the pump cover with the generator only partially out? Mine had no clearance at full extension but was accessible when pushed partially in. I understand the connector in question was at the "16 pin connector to the control board." Since I had trouble with the fuel pump relay once before and had to replace the relay I'm wondering if the problem wasn't at the relay connection instead. After external power made the pump run I was not in the shop, unfortunately, when the connector was blamed and tweaked for repair. When I am back at the coach I am going to pull the pump and check the connections personally since I missed part of the procedure due to shop rules........

tqqest · 07-21-2017, 10:32 PM

Thanks for the update Al,

Unfortunately on my current Allegro Bus, the bottom 6 inches of both sides of the generator are down inside and completely covered by the generator slide rails. There is only about 1 inch between the slide out rails and the fuel pump cover. I can reach the cover screws but could never get to the pump.

I am pretty sure both the fuel pump relay and the control board are up front. I am sure it one of those or, hopefully just a loose connection. I get 13 volts on the fuel pump wires when unplugged from the pump, but that drops to a couple of volts when the pump runs. I think you have the answer to my problem.

Thanks!