| Assorted fuel issues [message #323320] |
Mon, 04 September 2017 15:14  |
pzerkel
Messages: 212
Registered: September 2007
Location: Salisbury, IL
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Senior Member |
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I have a 1978' with a 455 with a Edelbrok performer intake manifold, with what I believe to be the original 403 carburetor installed. Electric choke on the carburetor, but I do not believe the choke has ever Been quite "right" since I Have owned coach. I.e. The choke plate does not completely close when I step up n the accelerator pedal.
I have only the original mechanical fuel pump installed. I did replace that pump ~3 years ago with one from one of the GMC Suppliers.
The coach has always been hard to start after it sits for a couple days. It always took lots of cranking, but would eventually start. I have suspected that my carburetor needs attention as I do not believe it should leak down that fast.
I feel I have a good understanding of how the two tanks are interconnected. Until about 3 months ago, my fuel gauge worked (and seems reasonable accurate-given miles driven and gasoline pumped). But now the gauge reads empty when set to AUX, but seems correct for the main tank. I presume this is due to loose connection in the line to the valve switch.
Also at that time, it became virtually impossible to start the coach, if it has sat for more than 24 hours. I can crank for two or three minutes and no joy.
I have pulled the fuel line out of carb and put in bottle, and I do not see fuel ( which I presume means I need to replace fuel pump again).
I have acquired a boat tank, and hook that to the input of the fuel pump, and it will start on the 2nd or 3rd revolution.
Now I come the part I do not understand....
If I run it from the boat tank briefly (30 seconds - 2 minutes), and then re-connnect the main fuel line, I can drive it that way for miles. I can shut it off, and as long as I start it within an hour or so, it will fire right up from the main tanks. Wait 24 hours, and forget about it though.
Is this is a failure mode of the mechanical fuel pumps?
I have read several of the threads on here about electric fuel pumps, and it seems a lot of people have them, and a lot of people have issues with them too. Also, there seems to be a lot of options about where and how to plumb them and wire them. I must admit, I like the simplicity of the mechanical pump, and I know it used to work better than it does now.
Part of me thinks putting an electric pump in now, would just mask whatever real problems I need to solve.
So what do I attack first?
Thanks.
Paul Zerkel
'78 Eleganza II
Salisbury IL (near Springfield)
[Updated on: Mon, 04 September 2017 16:53] Report message to a moderator |
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