RV Issue - Pretty Sure it's the Fuel Pump

[steppinstone]

I'm not sure but / If there is not a signal from the oil pressure switch the fuel pump will not engage. some one might correct me if i'm wrong. also I think the in tank fuel pumps only last for about 25 years. on my sisters coach they have 2 fuel pumps 1 in the tank which is a low pressure pump and 1 on the frame rail which is a high pressure pump .

[DAN L]

My Onan 5500 gas Genny runs fine with the oil switch connector disconnected and tied back.
With the switch connected my Genny would run for about 20 minutes and quit.
This is a known issue with Onan gennys.
Another known issue is the problem of dirty slip rings.
I cleaned mine, no help, it still quit in about 20 minutes.

[George Schweikle]

Benjamin,

Assuming changing the fuel filter doesn't solve your problem. When the engine was running, did you happen to notice if the fuel pump was making a whining noise?. This is said to indicate it will fail soon. Ours made the noise, I didn't think it was very loud, and naturally it failed while on a trip in California. The Coach.Net tow truck driver said his owner was experienced in motorhome repair, so we agreed to be towed to this shop instead of a very long trip to a service center and were allowed to sleep in the motorhome while waiting over the weekend and the new pump to arrive.

The independent shop that did our repair was small and privately operated, and these can be more flexible than a large dealer. Since you obviously have an internet connection, if you can find a similar shop in your area, with a good reputation, you may be able to sleep in the motorhome while the repair is being done.

Also, when our in-line fuel filter was dirty, a "check engine soon" light would occasionally come on. Changing the filter eliminated this.

Originally Posted by behing19

I am hoping to avoid the fuel pump repair, but we shall see. Going to order the filter today....

Benjamin Ehinger

[behing19]

Okay, I changed the fuel filter last Wednesday and the RV started right up with no issue. It actually started better and smoother than it has since the day we bought it.

We left New York and drove to Massachusetts on Saturday. We arrived in the afternoon and the campground was packed so we ended up in an overflow spot, which wasn't level. Due to being exhausted and only staying for the night we decided not to level the RV. It was leaning to the left if you're looking at it from the back and would have probably taken 3 levels of leveling blocks to get it even close to level.....not our smartest decision.

In the morning, it wouldn't start again. We had about 2/3rds a tank of gas, give or take. I could hear the fuel pump trying to pump gas and I am assuming the angle we were sitting at was causing all of the gas to sit in the opposite side of the fuel pump making it very difficult for it to get gas through the line.

I banged on the tank with a mallet and it started up, so we headed on our way to our destination in Maine. We figured, if we could get to Maine, we'd have 3 weeks to get everything figure out and I figure we had enough gas to get us the 130 miles we needed to go.

We stopped twice and didn't turn the RV off, once for food and once to grocery shop as quick as I could. Probably a total of 30 minutes of idle time on our trip.

About 15 miles from our final destination, I notice it started to sputter whenever I'd go up an incline, but it was fine if the road was flat or downhill. I was assuming we were about to run out of gas, so we took the next exit to try to get to a gas station. At the top of the exit ramp, it stopped running and I assumed we had run out of gas.

I had reset the trip odometer when we filled up before heading to Mass. We have a 50 gallon tank and had gone 263 miles (plus time idling) before we ran out. This seemed very low to me, as I had estimated we would get 7 to 8 miles per gallon and should have been able to make it. Obviously, I was wrong.

The Transit Authority in Main brought us gas (about 2 gallons) and put it in. Still nothing. At this point, I assumed due to the downhill angle, it was going to take much more than a couple of gallons to get gas to the fuel pump, especially if we were really out of gas. A very nice AAA guy also stopped (we are not members of AAA) and put out cones to direct traffic. He also put about 2 gallons of gas in, but still nothing.

We called Good Sam Roadside for a tow, which was going to take 3-4 hours, but they were willing to tow us the final 10 miles to our campground. However, they called back an hour later and said the provider had cancelled. About 30 minutes later, they had found someone to do it, but it was going to be another 6 hours of waiting. This would have made it about midnight before they arrived.

I decided to walk to a gas station and see if more gas would help. I got 1.75 gallons and put it in, but still nothing. Through all of this we had a total of $16 in cash and $27 in our checking account, so paying for a tow wasn't an option.

Finally, a very nice lady stopped to check on us for the second time and offered to let us use her AAA card if they'd get there faster. Shortly after a State Police officer stopped by and the very nice lady just offered to pay for our tow.

We were towed to our campground within 90 minutes and we are here for another 20 days. Now for my questions.....

First, the tow company unhooked our drive shaft and it's currently unhooked. If we wanted to fill our gas tank and try to start our engine, is that safe to do with the drive shaft unhooked? I know it's not safe to try and shift into gear, but I didn't know if it was safe to start the engine.

Second, should we assume it's the fuel pump and not just the filter at this point? It started just fine when we were leveled, but didn't when it was cold and we were not level. Are we stupid to think putting more gas in it would make a difference?

Third, can a mobile mechanic re-install the drive shaft or will we need to be towed to a shop for this type of repair?

Thank you again for all of your help. We have some time now and are working for some clients of ours to get some money to deal with all of this. We just want to make sure we are making a good, informed decision before we just start having work done on our RV/home.

Thank you,

Benjamin & Christina

[CampDaven]

You changed the filter, right?

[behing19]

Originally Posted by CampDaven

You changed the filter, right?

Yes. Changed the filter and it started up better than it has since we bought it last February. Actually sounded like an engine should when it starts.

[behing19]

Originally Posted by CampDaven

You changed the filter, right?

Sorry just noticed the error in my post and changed it.....I changed the Fuel Filter, NOT the Fuel Pump.

[Gordon Dewald]

Originally Posted by behing19

Sorry just noticed the error in my post and changed it.....I changed the Fuel Filter, NOT the Fuel Pump.

I would change the filter again. It seems possible you have sludge or something else in the tank that is getting to the filter. With the new filter on I would cut the one just taken off to see what is inside.

[CJ7365]

Yes you can start the engine without connecting the drive shaft just don't put it in gear.

Because you posted in an earlier post that you hit the fuel tank with a rubber mallet and it started again I would suspect a fuel pump, measuring the fuel pressure would confirm this

[behing19]

Originally Posted by CJ7365

Yes you can start the engine without connecting the drive shaft just don't put it in gear.

Because you posted in an earlier post that you hit the fuel tank with a rubber mallet and it started again I would suspect a fuel pump, measuring the fuel pressure would confirm this

How do I go about measuring the fuel pressure?

[CJ7365]

Earlier I believe you mentioned that you have the Chevy motor I don't know if its the 8.1 or 7.4 but there should be a Schrader valve located on top of the motor looks like a tire valve stem you can go to the auto parts store and get a fuel pressure kit it attaches to that and you should be able to check the pressure.

You can purchase the fuel pressure kit, and you can return it after your done for your money back

Orielly and autozone does this

[behing19]

Originally Posted by CJ7365

Earlier I believe you mentioned that you have the Chevy motor I don't know if its the 8.1 or 7.4 but there should be a Schrader valve located on top of the motor looks like a tire valve stem you can go to the auto parts store and get a fuel pressure kit it attaches to that and you should be able to check the pressure.

You can purchase the fuel pressure kit, and you can return it after your done for your money back

Orielly and autozone does this

Okay. Thank you for the help. This may be the step we take.

I think we are going to try to walk to the close gas station a few times with out fuel can and get the tank close to full. Then, see if it starts up. I still suspect that we ran out of gas or were too low to get any gas to the pump and I still think the 4-5 gallons put in were not enough at the angle we were sitting at.

If it won't start even with a close to full tank, it will be time to check the pressure and figure out if it's the pump. I may swap filters again, as was suggested by another member of the forum, as well.

Trying to take the cheapest, easiest route first and see where it leads us.

Thank you,

Benjamin & Christina

[behing19]

Originally Posted by Gordon Dewald

I would change the filter again. It seems possible you have sludge or something else in the tank that is getting to the filter. With the new filter on I would cut the one just taken off to see what is inside.

Okay. I just changed the filter again, but don't have the tools to cut open the old one. I can look in one end and it looks very clean.

I don't know if this signifies anything, but the first time I changed the filter it had no gas in it at all (had been sitting for about a week). This time, the filter was filled with gas (had also been sitting for about a week).

The new filter made no difference, although we have only put a total of maybe 8 gallons of gas in the tank since we thought we ran out of gas. Planning to put another 20 gallons in and try again.

Am I correct in thinking that 8 gallons may not be enough to get the gas to the pump? We are at a slight angle towards our passenger side back bumper, so I am assuming the gas we have put in would be collecting in that corner of the tank.

We have until 10/16 to get this figured out or the campground we are at is going to close down. Plus, we are working with limited funds (trying to take on work to get more money) currently.

Any ideas? Is it for sure the fuel pump?

[kwittintime]

Did you try blowing thru the old filter to see if it's stopped up?
Also with the filter unhooked you can put a hose on the line from the tank in to a jug and then turn the switch on and you should get gas pumped into jug if pump is working