No power to fuel pump, 89 Chieftain

knugent · 08-21-2012, 03:35 PM

I recently purchased a 1989 Chieftain with Chev P30 chassis, 454 gas engine. It was having fuel issues when I bought it, so I replaced the electric fuel pump/sending unit. I find that I have no power to the plug at the fuel tank. I found the fuse box under the hood, but there is no fuse marked "fuel pump". There are two relays on the block, but they are not marked, and there is one place for a relay, but none is present. Where might the fuse or relay be located, and is there possibly a fuel shut-off switch located somewhere? I have looked everywhere I can think, but to no avail. Winnebago cust. serv. say it is a Chev. issue, but no one I speak with at Chev. has any idea. I could sure use some ideas!

DonDee · 08-21-2012, 04:03 PM

Quote:

Originally Posted by knugent

I recently purchased a 1989 Chieftain with Chev P30 chassis, 454 gas engine. It was having fuel issues when I bought it, so I replaced the electric fuel pump/sending unit. I find that I have no power to the plug at the fuel tank. I found the fuse box under the hood, but there is no fuse marked "fuel pump". There are two relays on the block, but they are not marked, and there is one place for a relay, but none is present. Where might the fuse or relay be located, and is there possibly a fuel shut-off switch located somewhere? I have looked everywhere I can think, but to no avail. Winnebago cust. serv. say it is a Chev. issue, but no one I speak with at Chev. has any idea. I could sure use some ideas!

You won't have power unless you have oil pressure. Start the engine and then check for 12v or find the OP sender and go from there.
HTH let us know what you find.

knugent · 08-21-2012, 04:34 PM

Wow! I would have never guessed that! I will try to start it tomorrow & let you know what happens. Thanks.

knugent · 08-23-2012, 02:39 PM

DonDee, I started the engine this morning, had good oil pressure, but still no power at the fuel pump terminal. Any suggestions?

DonDee · 08-23-2012, 03:19 PM

Quote:

Originally Posted by knugent

DonDee, I started the engine this morning, had good oil pressure, but still no power at the fuel pump terminal. Any suggestions?

Go to the oil pressure switch and find the switch that supplies volts to the pump, broken wire, bad switch..check it out.

knugent · 08-23-2012, 07:43 PM

So, I would be concerned with the No. 3 in that picture? Where did you find something that clear and concise?

DonDee · 08-23-2012, 09:19 PM

Quote:

Originally Posted by knugent

So, I would be concerned with the No. 3 in that picture? Where did you find something that clear and concise?

#3 yes. I would unplug and check for volts with the key on. If one side has volts then I'd jumper across and see if the pump runs. If it runs the switch is bad if not then on to plan B which is a bit more involved.

I drew it myself...JK, a search engine found it!

DonDee · 08-24-2012, 06:30 AM

Maybe some help here:

http://www.irv2.com/forums/f65/help-...se-132307.html

wa8yxm · 08-24-2012, 09:11 AM

Quote:

Originally Posted by DonDee

You won't have power unless you have oil pressure. Start the engine and then check for 12v or find the OP sender and go from there.
HTH let us know what you find.

Close.. there is power to the pump when cranking too (There is a relay on the relay rack that takes care of that)

How do I know this: 1992 Chevy Lumina, the dang relay failed, in fact over time I had total electrical failure, but that's what went first. I installed an override.

DonDee · 08-24-2012, 09:53 AM

http://www.irv2.com/forums/f65/1985-...y-61112-2.html

DonDee · 08-24-2012, 09:58 AM

Quote:

Originally Posted by wa8yxm

Close.. there is power to the pump when cranking too (There is a relay on the relay rack that takes care of that)

How do I know this: 1992 Chevy Lumina, the dang relay failed, in fact over time I had total electrical failure, but that's what went first. I installed an override.

You are correct, the #3 siwitch is to shut off the fuel when there's no oil pressure. I am learning here as we go along too.

Theberrys · 08-24-2012, 10:15 AM

Congratulations to all posting in this thread (except me

)

Lots of facts and data here. This is what this forum is all about

Dick

knugent · 08-24-2012, 07:42 PM

You guys are giving me info that even the Chevy dealership mechanics can't. They have no idea!. I checked this morning, and DonDee, you are right on regarding the pressure switch. I have not been able to put a tester on it yet, though. I did note that it has a blue and an orange wire, and I kept digging around until I finally found a relay hidden behind the fuse block that had an orange and a purple wire, but the orange wire leaving the relay had been snipped and taped at some time, and I'm not really sure what that is all about. I am going to do some more digging this weekend, and I will let you know what I find. Thanks.

knugent · 08-25-2012, 02:27 PM

Well, I have an update. I did have power at the oil press./fuel switch, and I jumpered across it, but the pump still did not run. But, when I would join the jumper wires, I could hear the fuel pump relay clicking, so I was able to follow the sound to locate it. For future reference to anyone having this problem, THE FUEL PUMP DOES HAVE A RELAY, AND IT IS LOCATED ON THE FIREWALL, JUST ABOVE THE UPPER LEFT CORNER OF THE RADIATOR. It can be reached by removing the rubber cover between the hood and engine compartment.
Since I can hear the relay clicking, I assume it is good, but I still have no power to the pump. I traced the tan/white wire from the tank back to the fuse block. After it passes through the firewall, it goes behind the fuse block, and I lose it. I snipped it in two and direct-wired it, and the pump runs, so I know the wiring is good from the hood to the pump.
DonDee, you made reference to Plan B if the pump did not run after jumpering the oil press. switch. I think I am ready for Plan B.

DonDee · 08-25-2012, 05:08 PM

Quote:

Originally Posted by knugent

Well, I have an update. I did have power at the oil press./fuel switch, and I jumpered across it, but the pump still did not run. But, when I would join the jumper wires, I could hear the fuel pump relay clicking, so I was able to follow the sound to locate it. For future reference to anyone having this problem, THE FUEL PUMP DOES HAVE A RELAY, AND IT IS LOCATED ON THE FIREWALL, JUST ABOVE THE UPPER LEFT CORNER OF THE RADIATOR. It can be reached by removing the rubber cover between the hood and engine compartment.
Since I can hear the relay clicking, I assume it is good, but I still have no power to the pump. I traced the tan/white wire from the tank back to the fuse block. After it passes through the firewall, it goes behind the fuse block, and I lose it. I snipped it in two and direct-wired it, and the pump runs, so I know the wiring is good from the hood to the pump.
DonDee, you made reference to Plan B if the pump did not run after jumpering the oil press. switch. I think I am ready for Plan B.

Plan B WAS drop the tank but your pump is OK. I would replace the relay (we'll now make that plan B ;-) You are making progress.

knugent · 08-25-2012, 09:25 PM

Thanks. Yeah I dropped the tank about 3 weeks ago. That's what started all this. The innards of the tank were pretty horrific. She had been set up for about 4 years, and the fuel pump/sending unit were corroded away. They are all new now. I'm feeling much better now, thanks to your help.

DonDee · 08-25-2012, 09:39 PM

Oh yes I remember, I am following 2 threads about this issue on 2 different forums.