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Sat Feb 05, 2022 12:45 pm

ok so i have come to the conclusion that the fuel pump was so high, it made the air fuel ratio super rich. but it ran. now i cant seem to rich it up after adding gaskets under the pump. Before, after a few min, the spark plugs were black. now they are not getting fuel at all. is the pump just the fill the bowl or is it suppose to be part of the air fuel ratio itself.

Sat Feb 05, 2022 2:22 pm

https://www.thesamba.com/vw/forum/viewtopic.php?t=764139&highlight=fuel+pressure

Fuel pressure vs fuel volume. Stacking a lot of gaskets is not a great idea.

Sat Feb 05, 2022 5:32 pm

If you have fuel, check for spark at plugs. If you have fuel and plugs are firing it should run.

Sat Feb 05, 2022 6:07 pm

fuel is not reaching the plugs but im watching some go down the throat yet i dont kno if its not enough or im missing something simple

Sat Feb 05, 2022 7:26 pm

It sounds like you have an aftermarket fuel pump that's putting out excess of 5 PSI fuel pressure. The original Pierburg fuel pumps put out 3 PSI plus or minus a tiny amount.

As mentioned, shoving too many gaskets under the pump only moves the pump up and away from the pumps pushrod shortening the stroke. So, you're losing volume more than PSI.

The original German Pierburg fuel pumps for type 1, 2 and 3 using the correct 108 mm pushrod that sticks up 13mm above the fuel pump stand at it's max travel only required 1-2 gaskets to achieve a minor lessening of fuel pressure. Usually no more than 1/4 PSI.

Sun Feb 06, 2022 4:39 am

Are you not using a pressure gauge to check your fuel pressure?

Sun Feb 06, 2022 5:13 am

the fuel pump psi is like 4 and dropping by the time i get to the back of the car. i think im just not getting enough fuel as the spark plugs are dry now. and before they would turn black before i could even test drive. if you disconnect the fuel pump from a proper setup carb would the car run for a min?

Sun Feb 06, 2022 7:04 am

Sounds like you dont understand how a carburetor works. As a piston moves down thru a cylinder, it creates vaccum that pulls air thru the carburetor, that air pulls fuel out of the fuel bowl, and its that mixture of air and fuel that is sucked into the cylinder and ignited by the spark plug. So yes, the fuel pump just fills the bowl. As it fills the bowl, the float in the bowl floats on the fuel, until it pushes the fuel valve to the point the valve shuts off the fuel coming into the bowl. This is the same way your toilet tank maintains water ready to flush. If the pump has too much pressure say more than 3 lbs, it can overcome this valve and feed raw gas down the carburetor. Same thing can happen if the valve is no good, or if the float is set too high. The only reason for you to see wet plugs, is if there is no spark. If the plugs are black, your mixture is too rich. This could be for a variety of reasons. You need to go thru your carburetor settings, check that your float valve is in fact shutting off when its supposed to. Check your fuel pump pressure with a gauge. Check that you are in fact getting spark, and that at least your initial timing is set.
Hope this helps.

Sun Feb 06, 2022 2:23 pm

Good description Joe. See, I told these guys that you're smarter than you look. :D

8)

Yeah, joemama is right. The float bowl is like the tank on a toilet. It just holds fluid at the appropriate level for operation. It does NOT pressurize the float bowl. The fuel in the float bowl remains at normal air pressure. The fuel pump ONLY affects how the engine runs IF it is making too much pressure or too little pressure. The fuel pump does NOT pump fuel into the cylinders.

"the fuel pump psi is like 4 and dropping by the time i get to the back of the car."
This statement is confusing. How are you measuring the pump output pressure? Are you running the engine, then shutting it off and running around back to check a gauge there? If so, the pressure while running would probably be a lot higher than 4psi.

Sun Feb 06, 2022 2:59 pm

ok that helps. im trying to separate the problems. so i need to keeping trying to rich up the mixture till it starts. as long as the pump puts out enough to fill the bowl it should start as long as the mixture is right. i just wanted to make sure pressure from the pump to bowl was not needed. disconnecting the fuel pump on a good running carb should run till the bowl drops.

Sun Feb 06, 2022 4:49 pm

No, you need to remove the gaskets you used for the fuel pump, and use a pressure regulator, or replace the fuel pump altogether for one that does not need a lot of gaskets stacked.

Sun Feb 06, 2022 5:42 pm

i kno taking gaskets off would make it run again. but if the fuel bowl is full and after pretty much cutting the fuel off(stopping the flooding yet still 3+ psi). im using a fuel pressure gauge so 3+ as im trying to start it then falls right off. i would assume the air fuel mixture is off at the carb.

Sun Feb 06, 2022 6:19 pm

Stacking gaskets is causing your problem.

Once again fuel pressure vs fuel volume.

And your fuel pressure is not even good per your testing and psi readings after stacking the gaskets.

Get a new pump, or remove the gaskets and get a good fuel pressure regulator and get your psi and fuel volume set right.

Sun Feb 06, 2022 6:27 pm

To answer one of your questions. Yes, your car should run for a short time on only the fuel in your bowl. When I shut off my fuel at the shut off valve I installed near my tank, it takes at least 30 seconds to drain the fuel bowls and stop running.

Mon Feb 07, 2022 4:20 am

I just looked at your pictures and I see you do have a proper gauge to check pressure with and yes 5+ psi is too high. With the tank mounted as high as it is and so close to the engine I seriously doubt that you need a fuel pump at all. The tank should gravity feed that carb all day long so to eliminate the fuel pump question I would bypass it and go from the tank straight to the carb.

Here is what else I would check:

Take the top off the carb and check that the float valve actually seals by blowing in the fuel inlet and operating the float by hand. You could have a bit of crud lodged under the float valve. Then check that the float is set at the right height.

Check that the choke element works, is getting power and is adjusted properly. The instructions for that are in any VW repair manual.

Check that the fuel shut off solenoid is getting power and clicks/retracts when you touch it with the wire.

Reset all your mixture adjustments back to the starting point outlined in the repair manuals.

Now that baby should start and run long enough for you to fine tune it.

As I think about it some more... is there any possibility there is water in your gas? When you have the line off the carb, run some into a clear glass bottle and have a look.

Tue Feb 08, 2022 6:56 pm

oprn wrote: I just looked at your pictures ...

Pictures? I don' see no steenkin' pictures!

oprn wrote: ...
and I see you do have a proper gauge to check pressure with and yes 5+ psi is too high. With the tank mounted as high as it is and so close to the engine I seriously doubt that you need a fuel pump at all. The tank should gravity feed that carb all day long so to eliminate the fuel pump question I would bypass it and go from the tank straight to the carb.

Here is what else I would check:

Take the top off the carb and check that the float valve actually seals by blowing in the fuel inlet and operating the float by hand. You could have a bit of crud lodged under the float valve. Then check that the float is set at the right height.

Check that the choke element works, is getting power and is adjusted properly. The instructions for that are in any VW repair manual.

Check that the fuel shut off solenoid is getting power and clicks/retracts when you touch it with the wire.

Reset all your mixture adjustments back to the starting point outlined in the repair manuals.

Now that baby should start and run long enough for you to fine tune it.

As I think about it some more... is there any possibility there is water in your gas? When you have the line off the carb, run some into a clear glass bottle and have a look.

Otherwise, I agree with oprn. Although, at this point, I don't even know what carburetor is in the car or what sort of offroad VW it is.

Wed Feb 09, 2022 6:36 am

Just click on his name and then click on his photo album.

Wed Feb 09, 2022 6:37 am

Just click on his name and then click on his photo album.

Wed Feb 09, 2022 9:35 am

I viewed the photos as well.

There is a photo of one of those cheap dial a fuel pressure regulator in there. I think it was removed but not sure. It should be since it does not work well.

The fuel pump that is installed appears to be visually a generator model (straight up and down as compared to an angle), but it may require the shorter alternator pushrod depending on how far the push part sticks out on the bottom. This may be the problem using the wrong length pushrod.

Just a suggestion at this point.

Wed Feb 09, 2022 7:58 pm

I checked his page yesterday and at the time it said "0 photos". Then today it showed me the pics. Not sure what was up with that.

But anyway...

Yes I see a fuel pressure regulator. I've read horror stories from some people who have had trouble with those. But I've also read lots of horror stories from people who are using Holley and other high dollar fuel pressure regulators lately. I was looking for a regulator for my Chenowth because it was having trouble with fuel feed to it's HPMX carb. After reading more horror stories about the expensive ones than about the "cheap" dial type I decided to go ahead and buy another dial type. As it turned out, the fuel feed problem was that the PO had set the float level 19mm too low. He was apparently setting it with the float needle compressed, instead of hanging loose. So the regulator is still sitting in the garage in its box. I've been using that type since the early 1970s and have never had a problem with them. That does not mean that those currently being sold are certain to be good. I recently saw an offroad racer with a Holley regulator that when firing up the car in the morning before the race it spit the adjuster screw out of the regulator and spewed fuel all over before it got shut down. Right now, I don't trust ANY brand of fuel pressure regulator. But it's obvious that the OG on this thread needs a regulator. And I also want to point out that no matter what brand it is, it needs to be set using the fuel pressure gauge as he has done.