Fuel problems

[stumplord]

I have a 1986 Holiday Rambler Presidential! Will not stay running , I have replaced plugs and wires and distributor cap and rotor button both fuel filters and rebuilt carb,cleaned fuel tank replaced electrical fuel pump and cleaned out tank, replaced the sock! When I went to get the new fuel pump they couldn't cross reference the part number and gave me one that looked similar! Problem is when idling it runs fine when put under load it doesn't get gas and shuts off! I also replaced the front fuel pump that goes on motor! It has a 454! I think electronic fuel pump is to small!

[stumplord]

Where are the fuel pump fuses or relays?

[stumplord]

Can someone tell me where the fuel pump relay is and where I can buy an owner's manual!Camper sat a while but it was driven up from Fl to Ga about 300 miles and had no problems! Than sat another 2 or 3 months and given to me! Can not bring to a shop will have to figure it out with help from you guys and gals! A friend of mind said to take fuel line loose from bottom of mechanical pump and try and start and if fuel comes out fuel pump is working but that still doesn't address the problem of is it the right size!

[stumplord]

Replaced the rotor! Drained tank and cleaned and replaced fuel! Idles hard and fine! Finally test drive it and it made it only about a half mile and it shut off ! Tried restarting and nothing first few times then fired up and made it about another half mile then shut off! This time I poured gas directly into carb fired right up ! Then I drove it home and shut it off! I am curious if the electrical fuel pump is not keeping up with the mechanical fuel pump! Place I bought electronic fuel pump had no idea if it was the right size! How can I make sure I get right size efp numbers on old one does not cross reference!

[Krusty]

Are you certain its a fuel problem? When you replaced the distributor cap did you replace or at least have a look at the rotor? I have seen rotors with a hole burned through them with similar symptoms.

[time2roll]

DutchmenSport wrote:

time2roll wrote:
... then it is probably fuel. I assume you have inspected all the fuel lines.

When I read the OP's post, my very first thought was "Bad Fuel".

I have seen a carb filled with water and that does cause issues 😉
Fairly rare these days with the amount of alcohol in the fuel.
Seen bad right out of the box rebuilt carbs too. I would only get new if I had a vehicle with a carb (if available).

[enblethen]

Yes! I am not saying not to take it to a shop, but not dealers.
Many after market shops can do a much better job then most dealers on older model vehicles.

[MDKMDK]

enblethen wrote:
I would not take any vehicle to a GM dealer including a Ford! Yes, I know OP has Chev!

Can he bring it to you, then?

[enblethen]

I would not take any vehicle to a GM dealer including a Ford! Yes, I know OP has Chev!

[MDKMDK]

He's cleaned the tank and changed all the filters. I would think it's either vacuum or ignition. Maybe something in the "rebuilt carb" isn't opening or closing properly, causing a partial stall/shutdown. A clogged air filter will do the same.
Take it to a GM dealer and get them to have a look at it. It'll cost you an hour's labor.

[DutchmenSport]

time2roll wrote:
... then it is probably fuel. I assume you have inspected all the fuel lines.

When I read the OP's post, my very first thought was "Bad Fuel".

[time2roll]

You need a pressure gauge to quantify the issue. Seems unlikely that it is the fuel pump itself. Is the bowl of the carb empty as it dies? Does the engine recover immediately to restart or you let off the throttle?

Did you keep the old pump? If so post the number you need to cross.

When did this RV last run well? Was the transfer to failure and shutting down immediate or gradual? Any other work done near the time of failure?

Hard to get a feel for this old school stuff without a test drive. I am not convinced it is not an ignition problem. But if it just falls flat as you get in the throttle and then recovers and continues if you back off then it is probably fuel. I assume you have inspected all the fuel lines.

[enblethen]

Looked at several parts websites. The stripped chassis fuel pumps are listed between 20-35 GPM. I would look into the card floats, needle valve and needles. They may have an issue.
Fuel pump

[MDKMDK]

If it's a (GM/Chevy) 454, shouldn't you contact a GM/Chevy dealership and ask them?

[stumplord]

I need to find out how to find correct size electronic fuel pump!