We have a 1989 Safari serengeti, w/ a ford 460 and john deere chassis. I think possibly the fuel pump relay went bad. Fuel pump quit working when ignition is on, but we've rewired fuel pump with a manual switch to the aux. batteries and the pump works. Does anyone know where this relay is located? Part Number, whats going to it. Ahything? We do not have a manual or wiring diagram. Would like to put it back together the correct way.
You have a starter solenoid, that starts the fuel pump running while you are turning the motor over. Once the motor builds up oil pressure there is a oil pressure sending unit that keeps the fuel pump running. This is a safety switch that shuts the fuel pump off if you loose oil pressure. It is located at the back of the motor beside the oil sending unit. I'm not sure what number is on this, but the solenoid number from NAPA is ST404SB. I had to replace both of mine to make it run correctly. You are better to go ahead and replace both of them, neither one is very expense.
There is an "impact" relay somewhere that is required for all FI vehicles because of the high pressure and electric pump. It is "supposed to" sense an accident and shut off fuel so if the l;ines rupture you won't throw fuel on the fire! Early vehicles had a real problem with tripping them. They generally have a push button to reset, so the one you are describing could be it. when it is hooked up normal does the fuel pump run while cranking, or bnever runs? If it never runs should be the impact switch.
Ray, Cheryl, Cory & of course Miss Molly the four-legged child
Our serengeti is not fuel injected, yet there is a sticker on the front of the bus that says there is a safety switch for the fuel pump. When you turn on the ignition, the feul pump starts. The previous owner said to turn the key on, wait 10 seconds, then start cranking it over. This gives the fuel pump a chance to pressure the lines with fuel to the carberator. We were messing with electrical stuff, trying to hook the horn up, when we lost power to the fuel pump, so maybe we crossed a wire or something that threw that switch. Either way, we rewired the fuel pump, with a manual switch and it works, and we just drove the bus 100 miles so she's running ok. Without a manual, we just don't know where stuff is. We've only had this girl since january.
I can give you what ever help you need with that relay. This is a common issue with the Ford chaasis rigs. The harness is likely the failure problem with the relay, not the relay itself. As for the little grey box with a button on top, that it the intertia switch. All Fords with an electric pump from the factory had one, EFI or not. I can send you an email with the schematic for replacing the Ford Harness and relay with a Bosch 30A unit. Feel free to Email me for it at Stormyhusky@Hotmail.com.
Remeber, Deere/Oshkosh manuals are always available in my Ebay store!
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