I have a 1986 27ft Class C RV on a E350 chassis, 460 ci with about 140,000 miles on it. I inherited it when my Dad passed. I live in the southwest and I am have trouble with it, it seems to be a fuel supply problem, I think?

It runs fine on level ground, but we tried to go to the white mountains this weekend and could not do it. On an incline the engine would start to starve for power. At times we could only drive at 25 mph! It kind of seemed like it was running out of gas, if I tried to give it more throtle it would just die or fall on its face, if I let off the pedal and gave it gas again, it would run for a bit and then do the same again. We were lucky to get it back home. I replaced the electric fuel pump (on the side of the road) during the trip, but that made no difference.

Has anyone ever heard of anything like this? The engine ran cool the whole time! it has only one 40 gallon tank. I can find any other fuel pump on it. but dont understand all the lines going to and from the gas tank either?

I noticed tthere are these silver metal tubes that feed off the exaust manafold up to a cyinder looking thing on both sides of the block. One of the tubes is broken from the ex manafold and the manafold is plugged. Not sure how this got damaged or what this parts funcyion is but was wondering if this could be a problem

I'm lost, any help would be great!
TYVM
Ernie...


Thanks, this is my first post.

 

The tubes in the exhaust are A.I.R. injection tubes for the smog pump. Shouldn't effect performance.

Has the filter been changed? Have you scanned the computer for any codes?

 

Hi yes the filter was change a few months ago, I didn't realize this had a computer? Where would the port be?
thnx
LxMan

 

Ah! E-350 woes...

Also 460 engine, and fuel.

A lot of forums available for advice on the different things it could be - you have an older chassis that is probably stored more often than run.

My first rule when it comes to a fuel issue is to grab a fuel filter, but run berrymans B-12 through the system first. I bet there is a lot of junk in the system, and likely water in the fuel itself. Frankly - I'd keep some self tapping screws around with a wide top and neoprene washers in case the tank springs a pinhole leak from rusting (settled water).

But the issue itself may not be fuel - it may be VACUUM!

All the rubber parts in it, including vacuum dashpots are now more than twenty years old. Rubber rots, and can stiffen and crack as it ages and dries (Sort of like Mick Jagger, come to think - but I digress...) so checking all the rubber lines (vacuum, fuel, and brakes among others) is a must at this point.

Also hunt down the vacuum senders for the machine. Your tranny kick-down is probably a vacuum operated solenoid. Also even if you have an EEC (Or ECM, or ECC, or ABCDEFG...) there is a vacuum sensor somewhere - but it's called a "MANIFOLD ABSOLUTE PRESSURE" (MAP) sensor for reasons I've never fathomed... this device tells either the computer or plain old distributor that the engine is under load or it isn't. If the diaphram inside leaks - your timing will be way off! Especially if someone tweaked the timing to compensate for it without checking for a bad part...

I don't think it's a leaking fuel line, since it runs under normal conditions. A holed fuel line would suck air all the time - or you'd see fuel leaking under the coach. One of the two - depending on suction or pressure side of the pump.

DO THIS: Pull the BOOT in the cab, and see if you have a carbuerettor or what under there! If it's EFI, it's one can of worms. If it's carbueretted - it's another whole ballgame...

~Wolfie

 

Is this carbed or EFI? If it's carbed, my guess would be the float level is too low. 86 seems a little late for a carburetor though.

 

That's a good question. There's really only one way to know for sure - open it up and look in there!

Float level is a great thought, it should have occured to an old schooler like me....

 

It has as carburetor I think it is a Holly not sure yet. Gonna go look at it now. I had a thought that it could be related to the float, i guess an incline could effect that if it is stuck or something, but it does run fine on level ground.

Thanks for the replies.
Ernie..

 

yes sir it is a Holley. don't know what size, what is a double pumper. cause it has front and rear bowls?

Thnx

 

I just found a tag on carb by choke, says"Fred Jones MFG with stamped numbers
E5TZ EX is this realivent to what kind of carb this is?

Thanks again

 

Double pumper refers to the accellerator pumps - there is one for each float chamber.

On the side of each float chamber there is a round plug about 3/8 inch diameter. The floats should be adjusted so the fuel level just comes even with the bottom of them. There is a screw with a locknut on the top of each chamber to adjust the float level.

But I still think rubber lines and parts need looking at.

 

I think the 86 was the last one to have a carburetor.

 

I just found out the fuel line going into the carburetor is loose! I think that might be the issue here. I am going to replace the internal filter and tighten that line. I will post back either way.
Thanks for all the help and suggestions. I appreciate it very much!

Ernie

 

That would cause a leak - and it's a good thing you found it! But it's on the pressure side, so the jury is still out on this issue.

I'll stay subscribed...

Hmm, if there WASN'T a leak, this could be a fuel pump itself.

 

Can you explain "Its on the pressure side"? Wouldn't everything after the pump be on the pressure side?
Seems to me but don't know, if it was related to vacuum wouldn't run rough all the time. After tightening the line today I put some seafoam in it and took it for a ride with the inside cover off. It ran smooth as can be.

Also LxMan mentioned a computer, I can't locate one, does anyone know if this year had one?
Thanks,
Ernie

 

You may also want to check the fuel tank for an electric fuel pump. A lot of motor homes have a pump in the tank as a supplement to the engine mounted fuel pump.