fuel issue

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zabo
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fuel issue

Post by zabo » Mon Mar 16, 2015 6:47 am

I need some trouble shooting help.
As you may have read in other threads i've been having fuel pump issues due to an old leaky one then a nightmare of rebuild kits and aftermarket pump.

I finally found a used 40hp screw inlet type pierburg pump and thought i had it running pretty well. It was never running as good as it used to but i chalked tht up to a tired diaphragm.

Now im having an issue where the car starts up fine and drives fine for about 5 minutes then starts bogging down.
I swapped out the carb with a spare and had the same symptoms.

So let me know if yall have any ideas- Im rebuilding a 36hp right now so id much rather spend $200 on a new 36hp muffler than a vintage werks fuel pump.
60 beetle
78 bus

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SlowLane
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Re: fuel issue

Post by SlowLane » Mon Mar 16, 2015 8:29 am

Heat riser clear? Pre-heat hose in place and functional? Measured the fuel pressure with your new pump? Does your exhaust actually provide a correct path for the gasses through the heat riser (ie. Does it have a path from one exaust port to the tailpipe, or does it simply connect the #2 and #4 exhaust ports?) Functioning thermostat?
'81 Canadian Westfalia (2.0L, manual), now Californiated

"Wisdom comes from experience. Experience is often a result of lack of wisdom."
- Terry Pratchett

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zabo
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Re: fuel issue

Post by zabo » Wed Mar 18, 2015 2:09 pm

Thanks slowLane- it looks like i need to get my hands on a fuel pressure gauge.
I cleaned out the heat risers 2 yrs ago- i hope they are not clogged again.
Exhaust is the stock setup
60 beetle
78 bus

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SlowLane
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Re: fuel issue

Post by SlowLane » Wed Mar 18, 2015 2:52 pm

zabo wrote:Thanks slowLane- it looks like i need to get my hands on a fuel pressure gauge.
I cleaned out the heat risers 2 yrs ago- i hope they are not clogged again.
Exhaust is the stock setup
I was focussing on the heat riser and pre-heat system in my suggestions because the symptoms sound more like a carb icing problem than a fuel pressure issue.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"Wisdom comes from experience. Experience is often a result of lack of wisdom."
- Terry Pratchett

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Amskeptic
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Re: fuel issue

Post by Amskeptic » Thu Mar 26, 2015 11:16 am

zabo wrote:I need some trouble shooting help.
starts up fine and drives fine for about 5 minutes then starts bogging down.
I swapped out the carb with a spare and had the same symptoms.
You *need* to jump on it exactly when it occurs. Drive it until it screws up. Now try to define the variables. Does it get worse when you demand more fuel?
Does it recover if you let it idle a few minutes?
Does it stay unhappy even if you let it "recover" by idling a few minutes?
Colin
(fuel filter clean?
(do you have a tank outlet sock/screen?)
(coil hot?)
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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zabo
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Re: fuel issue

Post by zabo » Wed Oct 14, 2015 7:28 am

Just wanted to update this thread.
About 3 months ago I finally gave in and spent the cash to get a Vintage Werks fuel pump.
-money well spent.
I put it in the car and it fired right up. Drove fine for about a week then one day after work I
couldnt get it started.

I pulled of the top of the top of the carb and the bowl was empty, sticking needle valve.
I had another in my ashtray so swapped them out and was on my way.
Happened again a week later. Both of these valves where from recent rebuild kits.

I checked my parts box and found an old one marked solex and it has been smooth sailing since.
60 beetle
78 bus

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Amskeptic
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Re: fuel issue

Post by Amskeptic » Wed Oct 14, 2015 7:46 am

zabo wrote:Thanks slowLane- it looks like i need to get my hands on a fuel pressure gauge.
I cleaned out the heat risers 2 yrs ago- i hope they are not clogged again.
Exhaust is the stock setup
You can do a feel test on the heat riser (before it gets to branding temperature, hello) to see if heat is radiating through.

If your symptoms occur on a thoroughly warm engine, you can move beyond the temporary bogging that a clogged heat riser would give you.
Does your fuel tank outlet have a mesh sock?
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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zabo
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Re: fuel issue

Post by zabo » Wed Oct 14, 2015 4:47 pm

yes. i did end up removing the risers and cleaning them out real good.

the tank has the mesh sock but i am seeing a lot of junk in my fuel filter.
i had a radiator shop clean and coat the tank abt 8 yrs ago. i guess its that time again.
60 beetle
78 bus

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Amskeptic
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Re: fuel issue

Post by Amskeptic » Wed Oct 14, 2015 6:35 pm

zabo wrote:yes. i did end up removing the risers and cleaning them out real good.

the tank has the mesh sock but i am seeing a lot of junk in my fuel filter.
i had a radiator shop clean and coat the tank abt 8 yrs ago. i guess its that time again.
Seeing as I have six classic cars all but one of which sit for embarrassingly long periods of time and have never ever had a fuel tank or crusty filter issue with any of them, amy I ask if you keep your tanks full, refill between 3/4 and 1/2 down, and do not let them sit for so much as a week without topped off tanks?
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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zabo
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Re: fuel issue

Post by zabo » Thu Oct 15, 2015 4:34 am

hmm the past few years i was driving it daily so filled up every week and a half when it hit reserve. guessing it was probably low when it sat for a few months during the time i was having fuel pump issues.
60 beetle
78 bus

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