P30 Fuel Pump Service Life?

The fuel pumps run 10 to 15 sec when the ign is turned on to prime the fuel rail, once started the oil pressure switch proves the motor is running and keeps fuel flowing on the GM's
fuel pumps is one thing that can go at any time like a headlight bulb, best to go with the OEM type, found less problems. also if you rig has steel lines coming out of the sending unit make sure the lines are in good condition as well, not a bad idea to coat the top side of the gas tank and lines with undercoating, some of the newer fuel pumps come as an assemble, fuel pump/ sending unit all plastic , and plastic lines and no rust problems..

Thought I'd mention this, dropping the tank is no problem once you get the fuel out of the tank. A floor jack works the best with some 2x6 on the jack, some 4x4's on the floor to lower the tank onto and some clear safety glasses to keep the dirt out of you eyes.

Nice! Those are some respectable miles. Thats like 4000 hrs plus. This is a good data point. Thanks

workhorse service rep told me it was 1000 hours.
mine dies after 187000 miles
2002 winnebago chieftain

Depends, in tank units usually just die. Engine mounted units will feel like your running out of gas when you put a heavy load on the engine, then eventually die. I have 125k on my original 98 chevy in tank unit. My 2nd gas tank is on it's 3rd pump. That said, EGR valve and MAP sensors are usually pesky critters when it comes to maintenance. Also, if you are having higher rpm problems then look at the TPS sensor.

Well Eddie, I just replaced the pump after dropping the tank. The main reason was there are a lot of people with units as old or older than mine that are having fuel hose cracking and sucking air. On my tank there was a custom hose that I had to have made up because it had hydraulic style fittings on the ends. There were 3 or 4 hoses that I replaced so if something was to happen down the road I could get to the rest. There was absolutely no way to get to the top of the tank without dropping it. I used a harbor freight hydraulic table to drop it. I had to jack up one side of the MH about 4 inches to be able to roll it out. It took awhile to find and order the intank pump. Make sure you get the correct "O" ring for sealing up the pump assembly. Now that I have done this my fuel gauge is off. Maybe that will be another day.

The normal power to the fuel pump goes through the oil pressure switch.
The fuel pump relay is to charge the line for easier startup. It is indicated as a "primer" on my drawing.
The orange wire at the fuel pumper oil pressure switch comes off the 20 amp ECM/fuse and is splice to the normally open contact on the fuel pump relay which is controlled from the ECM pin F6
The grey wire on the oil pressure switch feeds power to the pump itself.

RLS7201 wrote:


But the fuel going through the pump offers more cooling than the fuel surrounding the pump. I still don't see the added value of cooling from the outer surface of the pump. The pump itself generates little heat, which is carried away by the fuel flow.

Richard

Do a quick search on the internet about what causes in tank fuel pumps to fail and you will see many EXPERTS saying that low fuel is a major cause of failure. Heed their advice or ignore them is your decision.

Rick Jay wrote:

RLS7201 wrote:
I've seen this rationale many times. But why would fuel tank level affect fuel pump temperature if the pumped fuel flows through both the pump and the pump motor housing?

Richard,

The fuel pumps to which they are referring are inside the gas tank. By keeping the tank level high, the gasoline surrounding the pump acts like a heatsink to keep the pump cooler. If the gasoline level drops below the top level of the pump then the pump will run warmer because of the loss of this cooling action, potentially accelerating wear and increasing the likelihood of pump failure.

To that, the other variable I'd add is to make sure the gasoline stays fresh in the tank and to add fuel stabilizer if the fuel will sit in the tank for 6 months or more. I find this especially true for my small gasoline engines, and wonder if the fuel pumps could also be effected by a build up of varnish. The price of a bottle of Stabil is cheap compared to a new fuel pump and installation. Pluse the Stabil helps keep the generator fuel system in top shape too.

~Rick

But the fuel going through the pump offers more cooling than the fuel surrounding the pump. I still don't see the added value of cooling from the outer surface of the pump. The pump itself generates little heat, which is carried away by the fuel flow. Externally mounted electric fuel pumps cool quite well from the fuel flowing through them.

Richard

enblethen wrote:
The fuel pump relay only operates for a few seconds when the ignition switch is turned to "ON". After that the power comes through the oil pressure sending unit.

Are you sure you're not just saying that the ignition initially powers the relay and then the relay is held in by the sending unit.
I would think that the relay itself is always in use and with whatever might be powering it.
Also thinking that the sending unit is in essence a ground return for the relay, as well as it is for the oil pressure gauge.