Fuel Pressure? Weber Progressive 32/36 DFEV, T-4 1800

haydenslides

I have a ’74 Bus with an 1800 cc Type 4 engine. It is fitted with a Redline Weber conversion Kit, K297 which uses a Weber Progressive 32/36 DFEV carb. The Weber 32/36 instructions state that the carb requires 3 lbs maximum fuel pressure.

The van is currently fitted with a Mr. Gasket 42S electric fuel pump (rated at 2 to 3.5 psi) which is putting out only 1.5 psi at my fuel pressure gauge. As it stands now while I’m testing, the tank is connected to a new fuel filter which is connected to the 42S fuel pump which is then connected to my fuel pressure gauge.

The engine is hesitating and bogging under heavy throttle. I am assuming that at least part of the problem may be inadequate fuel pressure. I’m thinking that I need to switch to a fuel pump with higher psi output.

I was considering the Mr. Gasket 12S electric fuel pump, which is rated at 4 to 7 psi. I have a Weber fuel pressure regulator which is adjustable for 1.5 to 8 psi flow.

My question is: Would the Mr. Gasket 12S fuel pump be a good option? I’m assuming I can drop my fuel pressure to the carb to 3 lbs. If I install the fuel pressure regulator between the fuel pump and the carb…shouldn’t this be correct?

I’m a little concerned that since my current fuel pump (Mr. Gasket 42S) is rated for 2 to 3.5 psi and I’m only getting 1.5 psi out of it, that a higher flow Mr. Gasket pump would also be flowing less than what it’s stated output is…

Thanks for any input you may have! I am finally spending a little more time on Bonnie the Bus and would like to get her rolling again Smile

-haydenslides

Randy in Maine · Posted: Tue Jul 28, 2015 12:43 pm Post subject:

Are you providing for heat to this center mounted carb?

What distributor are you running and how do you have it timed?

SGKent · Posted: Tue Jul 28, 2015 12:52 pm Post subject:

1.5 PSI is a little light at 8,000 RPM but it probably doesn't matter at 60 MPH and 3500 RPM. Regardless I'd shoot for 2 1/2 psi with that carb. 4 or 5 is too high. All that said, many of these progressives have been so tampered with that fuel pressure is the least of your worries.
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Tcash · Posted: Tue Jul 28, 2015 1:10 pm Post subject:

How to make a progressive work properly on a VW engine.

Good luck
Tcash

haydenslides · Posted: Tue Jul 28, 2015 1:25 pm Post subject:

thx for the responses! I'm using a pertronix electronic ignition with a 009 distributor and MSD Blaster2 coil. as of right now it bogs so badly that I'm not getting out of second gear, so not much over 15-20 mph... the progressive carb hasn't been messed with since coming from Redline...the former owner (my buddy) just installed it and didn't do anything else with it. And no, no heat is being supplied to the carb. Right now I'm just trying to get it to run good enough to go to the store, a new carb setup isn't in the budget (starving college student Laughing

)

I've static timed the engine.

Cash thanks for the reply, I'll check out your link!

So will I be ok if I have say 5psi coming out of my fuel pump and use the fuel pressure regulator to turn it down to ~2 1/2 psi?

-haydenslides

Randy in Maine · Posted: Tue Jul 28, 2015 1:29 pm Post subject:

Well at least time it to the 28º BTDC when all of the advance the distributor has to offer is all in ~ 3500 RPMs.

See if that changes how it drives.

SGKent · Posted: Tue Jul 28, 2015 1:34 pm Post subject:

busdaddy · Posted: Tue Jul 28, 2015 1:36 pm Post subject:

A 74 should have a strainer in the tank as well. We should also discuss vent lines and charcoal canisters.
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Wildthings · Samba Member Joined: March 13, 2005 Posts: 50352

You may have a screen on the inlet to the pump. Wouldn't hurt to pull and clean it. FWIW progressives don't seem to need much in the way of fuel pressure, that just isn't one of their common issues.

Some electric pumps will put out varying pressure depending on the angle they are mounted at.

mnskmobi · Posted: Wed Jul 29, 2015 7:57 pm Post subject:

What jetting do you have?

Wildthings · Samba Member Joined: March 13, 2005 Posts: 50352

One way to determine if the fuel pump is the problem is to get up to speed and then let the engine coast for 10ish seconds. Now when you hit the gas do you get good power for 5-10 seconds and then does it drop off? This is not including any bog when you first hit the throttle.

SGKent · Posted: Wed Jul 29, 2015 10:38 pm Post subject: Fuel pump test

Aerindel · Posted: Fri Aug 07, 2015 12:16 am Post subject:

I have a progressive on my sand rail that I have been fighting for about a year and finally have it running pretty good.

Things that I had to fix.

un-capped vacum port on carb.

re-jetting.

un drilled heat risers. This was a big one. I literally had a puddle of liquid gasoline laying in my intake before I fixed this.

Hot air intake.
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Homemade woods/street, bug out rail. IRS, Balljoint front end. 1967 1600cc DP, Weber 32/36 progressive, tri-mil quiet pack. Rear only cutting brakes.

http://www.thesamba.com/vw/forum/viewtopic.php?t=630046


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