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Home » Public Forums » GMCnet » PowerLossProblem - Gatsbys' Cruiser is ending the year on a good note: (It's been a very VERY long haul, a wheel barrow of money and lots of frustration)
PowerLossProblem - Gatsbys' Cruiser is ending the year on a good note: [message #325172] Thu, 19 October 2017 21:11 Go to previous message
GatsbysCruise is currently offline  GatsbysCruise   United States
Messages: 261
Registered: January 2017
Location: Waukegan, Illinois
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Senior Member
I've watched a lot of message go by with terrible problems, but most of the coaches were still moving.

I took a lot of advice on this fiasco.
To catch up....

I connected an external fuel tank to the mechanical fuel pump and she ran like a top, took her down the highway and was able to get to 75 without missing a heart beat. It is definately the fuel system.

I have replaced the fuel hose from the new solenoid valve to the mechanical fuel pump.

The first test was from the main tank, no electric fuel pump and it wasn't so good. She ran until the float bowl ran out of fuel then died. How do I know this? The reserve tank has an electric fuel pump. When I turn it on to prime the line, I can hear the float bowl fill, with its gurgles and such. It isn't a plugged line or I wouldn't run at all and it isn't a damaged hose or I would see fuel on the ground. this one has to be the hoses or pick up in the tank. -- The mechanical fuel pump is bad you say? Can't be because when I used the external fuel tank, I used the mechanical fuel pump and it ran like a top...

The second test was on the reserve tank, with the electric fuel pump on.
She started and ran fine. we never finished the carb adjustments because she wouldn't run long enough, so I adjusted the idle a bit and ran her for half an hour. she ran strong and smooth. This is good, very good.
I did try some high rpm tests and she ran ok. I felt confident that we had made some ground on this one.

The third test was on the road.
Started her up on the RESERVE tank with the Electric fuel pump, and let her get the engine warm. Put her in Drive and slowly pulled down the drive way. Felt so good to be moving again.
Turned onto the road and slowly increased speed to about 20. I was nervous and hoping for the best. Got onto a deserted road and drove up to 35mph. (This was the last failed speed when I tested, that failed and I lost power). She held the speed just fine. sped up to about 35 and she just ran like a top.
I was feeling pretty good now, up to 45 mph, enjoying the ride of my GMC motorhome, listening to the engine purrr down this road.
I decided to see if we are clear of the problem or where the limit will be.
I took her down a not so busy highway, turned on and started a slow climb in speed. I made it to about 50-55 mph before the power loss showed up again. This is not the best result that I wanted but I AM DRIVING AGAIN. My limit is 50-55 MPH.

My thoughts are there has to be an air leak in the fuel tanks. We must be sucking air from the tank which when the mechanical pump was running, it sucked enough air to run the float bowl dry.

It is harder to figure the RESERVE tank. The electric fuel pump is pumping fuel from the sol fuel valves, to the mech fuel pump and as it does this, it gets air from the res tank, I think!!!..

The project will go on hold until SPRING but I am able to drive her now in town. I am again enjoying the ride and sounds of the GMC motorhome after all this time.

This spring I need to drop those tanks and have not come up with any idea how I can accomplish this yet, but I have 6 months to think about it.

MANY MANY thanks to those who have offered ideas suggestions and just read my rants. I've needed all the help I could get. and it was all good advice, I'VE GOT 55 MPH NOW!! Laughing Laughing Very Happy No weeds growing around her bumpers anymore lolol.

Thanks all for your thoughts

Gatsbys' Cruiser

GatsbysCruise. \ 74GMC260 Former Glacier Model style. \ Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO - UBUNTU VOYAGER - Berzin Auto Center

[Updated on: Thu, 19 October 2017 21:32]

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