GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.
Home » Public Forums » GMCnet » Trip Report II (Mechanicals)
Trip Report II [message #364974] Thu, 24 June 2021 23:20 Go to previous message
Carl S. is currently offline  Carl S.   United States
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma:
Senior Member
In my previous trip report, I stated that the coach ran great the whole trip EXCEPT for some fuel starvation issues while climbing long steep grades in extremely hot temperatures. Here is the back story and the reason I was a little surprised by this:

I have had "vapor lock" issues ever since the first drive with this coach back in 2008. I have done nearly everything conventional wisdom says should fix this problem, from installing a heat dissipator under the carburetor, Making sure all my fuel filters are fresh, adding an electric pusher pump by the gtas tanks, installing a Gary Rockwell aluminum intake manifold, without a heat crossover, mking sure my fan clutch is working, and even insulating the bottom of my gas tanks.

Finally, after rebuilding the engine and transmission about 3-1/2 years ago, I relocated my fuel hoses to the OUTSIDE of the frame, added a canister type filter, and installed a Carter 4070 electric pump, fed electricity by a relay, also outside the frame, and the problem was finally gone. For a while anyway.

The last few hot weather Summer trips, it has begun to happen again, usually after several hours of driving in the heat.

I guess I will change out all the filters again, check the integrity of the tank bottom insulation, and probably do a tune-up and see what that does.

I suspect the quality of the gas may have something to do with the problem and I admit, I am guilty of buying the cheapest gas I can get. I have had mixed results with gas from Flying-J and even Chevron in the past, so I'm not convinced that's it.

Do electric (or mechanical for that matter) fuel pumps tend to get weaker as they age? The Carter is only a little over three years old and has about 25,000 miles on it. I will replace it if the consensus is that they wear out and it might help. b ut it seems like it should not be the problem either.

It's very frustrating to know you have the power to easily climb a long grade, but you find yourself limping along the shoulder at 20 mph until you top the hill.

Any ideas or advice?

Carl Stouffer '75 ex Palm Beach Tucson, AZ. Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member

Report message to a moderator

[Message index]
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: [GMCnet] Rear Hub/drum/rotor diameter
Next Topic: [GMCnet] Steering Turns
Goto Forum:
  


Current Time: Tue Oct 01 02:23:48 CDT 2024

Total time taken to generate the page: 0.03400 seconds
.:: Contact :: Home ::.

Powered by: FUDforum 3.1.1.
Copyright ©2001-2021 FUDforum Bulletin Board Software