hypothesis: failing fuel pump?

[jtauxe]

An odd thing happened yesterday after I did a compression test and checked the timing on the single cab. This is a 1975 pickup with an 1800-cc CB case and newly rebuilt heads from Headflow Masters.

It may be that the futzing I did is purely coincidental to the current problem, however...

When the engine got rebuilt, I got a new electric fuel pump and installed it underneath, more or less above the transaxle, and screwed into the floor. Not having rubber mounts at the time, it is screwed directly to the metal floor, and so made quite a racket with ignition ON. But yesterday, as I fired it up for a test drive, I noticed that the fuel pump was no longer making its racket. The engine started anyway, however, and I did some driving.

But it would stall at odd times, and was sometimes not happy maintaining an idle. It would stall out while cruising along at 40, forcing me to the side of the road. After awhile (5 minutes?) it would start again (with some persistence), and then I could go a ways again, but then it would stall out again. I finally limped home.

Since the fuel pump quit its racket, I figured that perhaps it had failed, but if it had failed, how can I go at all? It seems to me that with a fuel pump failure, I would not get the engine started, much less go anywhere. I am trying to reconcile the data with my failed fuel pump hypothesis, but it does not make sense to me.

Is there a possibility that even without the fuel pump working, fuel can drain from the tank into the line by gravity, and provide enough fuel for brief periods of running? Could the carburetors somehow suck fuel up the line for a bit of time? If so, then I may stick with the failed fuel pump hypothesis.

If there is no way the truck could run with a failed pump, then what else could be causing this behavior?
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[suffecool2]

When my electric pump failed, it would still run, although very badly. But I didn't try to go anywhere though. Maybe a intermittent clog in the fuel line?
_________________
'71 Hightop - rolling resto/customization in process
'87 Golf - tranny's toast, but still runs
'70 bone stock Westy - gone

[Wildthings]

Since the tank is higher than the engine, gravity may be able to supply enough fuel for the engine to be able to idle and run short distances.

[FreedomBuild]

[jtauxe]

No relay -- it is just powered off the coil, with an in-line fuse.
I believe it was a Facet pump, 3.5 psi. Failed in just a few months.
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[FreedomBuild]

The PO had a Carter fuel pump wired to the ignition coil but after going through two in a month I decided to get a Facet electronic pump and wire up a relay. Easy peasy. Also you won't have to worry about your pump running on when you have the ignition on or running if you get into an accident. Here is my setup on my 73 Campmobile. I haven't had an issue since.
-- Knocks on wood--

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_________________
1973 Campmobile rustoration in progress..

1700 Type 4 engine
Manual Transmission
Pertronix Mechanical advance distributor
Pertronix Flame Thrower coil
Weber Progressive

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[Randy in Maine]

[jtauxe]

Is there another brand that you would recommend?

Something that will deliver 3.5 psi...
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[Randy in Maine]

I put one of these on a bus with dual carbs a few years ago and it is still working well and quiet....

http://vwparts.aircooled.net/Rotary-Electric-Fuel-Pump-3-25-psi-7mm-Fittings-p/rotary.htm

or

http://www.cbperformance.com/ProductDetails.asp?ProductCode=3193

[FreedomBuild]

[jtauxe]

[Randy in Maine]

I think that the FI pump has a 10mm low pressure line that goes in from the fuel filter and a 7mm high pressure line leaving the pump.

This one uses a 7mm or 5/16" line on each side.

Of course that was about 4 years ago, and I can't remember what I had for breakfast this morning.

I used to say it is not the years but the mileage, but the years might have something to do with it also.

[jtauxe]

Well, Randy, they say that the memory is the second thing to go.

What I was really interested in is the overall diameter of the "can". That is, would this pump fit into the same clamp that holds the FI pump? Hose diameters I can manage.
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[germansupplyscott]