P30 Fuel Pump Service Life?

[Cousin_Eddy1]

Trying to be pro active an do preventative maintenance. How long with the fuel pump last in a 1995 P30 chevy motor home chassis? Is it mileage, time or both? Anyone have to replace theirs already? Thanks.

[lonfu]

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.

[BrianinMichigan]

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.

[enblethen]

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.

[rgatijnet1]

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.

[RLS7201]

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

[tropical36]

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.

[enblethen]

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.

[booty51]

I just went through this exercise with a 1996 P 30, thinking fuel pump is bad . there is a way to test fuel pump thru the fuel pump relay to determine if fuel pump is bad. you can check the fuel pump ground and bypass the relay to see if pump runs using a small jumper and a volt ohm meter to check things out.I also was thinking of cutting hole in floor but H2o tank was in the way. It turned out it was a bad fuel pump relay. I do believe in P M but like others have said where do you draw the line. Oh yeah the relays on the 96 p 30 are on top of the steering column in the dash of mo ho, I looked forever to find them. You may also look under coach to make sure nothing is in the way to drop tank. My levelers had a steel brace going across underside of fuel tank from one jack to the other that was in the way of tank coming straight down but I think tank could be dropped enough and lowered on one end to maybe get it out . Read my post " chevy gear heads" it cover some of the issues about the fuel pump.

[tropical36]

enblethen wrote:
Many basement style set ups you cannot get to the fuel pump through the floor because there is holding tanks in the basement.
Look hard before starting to cut holes.
My rig has holding tanks in way from the top and stabilizer brackets from bottom.

Being careful is the key here.
Just so happens that my fuel tank is directly under the floor under the bed and the storage tanks are more forward, but......and there's always a but, the fresh water tank is under the bed and must be removed before doing anything else. Doesn't look all that bad though and a lot better than dropping the tank on this puppy.
Probably won't however, since I'm old and tired, but of course will do the should've, could've routine, if and when it gets towed to the garage and even though the proper diagnosis would need to be made, before going after the fuel pump, even if one had an above tank, access plate.
Back to the access plate routine, at least one could just get to a campground for this, take your time and considering that all the work can be done from the inside now, with the fresh water tank temporarily stored between the cockpit seats.

[enblethen]

Many basement style set ups you cannot get to the fuel pump through the floor because there is holding tanks in the basement.
Look hard before starting to cut holes.
My rig has holding tanks in way from the top and stabilizer brackets from bottom.

[mike_brez]

On my old 1994 PaceArrow P30 I got pretty good at removing the fuel tank. I could have it on the ground in about 20 min. Two straps around tank a two bolts on each end with my motorcycle jack under the tank. I had a bad rust issue from previous owner. I know there was a write up here about installing a frame mounted pump. Mine was still good and working but I replaced it after I got my fuel tank lined.

[tropical36]

Cousin_Eddy wrote:
Trying to be pro active an do preventative maintenance. How long with the fuel pump last in a 1995 P30 chevy motor home chassis? Is it mileage, time or both? Anyone have to replace theirs already? Thanks.

About 96K on ours and keep thinking that maybe I should replace it with another OEM and put and access through the floor in the process.
Gonna be a little late for doing so, if on the road and a shop will undoubtedly drop the tank and still not having the floor access, unless you really want to pay and it will be bad enough, the way it is.
So two fold with this reasoning...
One is to begin again with a new one and keeping the old one for a spare and the other is to have the access plate now available for another possible replacement without ever having to drop the tank in the first place.

[enblethen]

You could experience loss of power. This could also be a fuel filter clogging.
I carry a spare fuel filter and proper wrenches to install it. Check yours out to see what is required. You may want to change it more often. I change our filter about every 5-10,000 miles.
Some people say that you may have engine back firing caused by fuel pump failing.

[Dachristianman]

I believe that replacing mechanical items when there is no indication of failure is a bad way to approach these things. If that's the case, where you stop? There are so many items that could be replaced, that you would be just as well to buy a new motorhome. Wheel bearings, water pump, CV joints, alternator, PS pump, electric fan motor, clutch fan assembly, and on and on we go. The replacement items aren't built as solid as the original items, so run them until they start giving you trouble and then replace them. Instead of throwing money away on replacement parts before they fail, purchase a good tow policy and sleep easy.

Happy motoring.

Tom

[Cousin_Eddy1]

Lots of good points. Thanks! I will let it ride then. The rv gets used evey 6 weeks or so. No chance for old gas. We have Good Sam if it does strand us. I too have replaced parts and had the new ones fail. So, i guess you can say the factory one is known good.

When the pump fails, does it give you warning? Like fuel pressure starts to drop and it pops thru the intake for a while? Or, does it just die?