78 FI Super Convert.Will Not Start When Hot.

[lakes73]

Just installed new fuel pump...If I push in the AFM flap and try to start the car,the fuel pump runs,but is making a strange gurgling sound...the car will crank and crank,but no fuel is making it back to the engine,I pulled the hose off the cold start valve,no fuel..What do I look for?..Thanks for any help,Chris.

[SlowLane]

Just installed new fuel pump...If I push in the AFM flap and try to start the car,the fuel pump runs,but is making a strange gurgling sound...the car will crank and crank,but no fuel is making it back to the engine,I pulled the hose off the cold start valve,no fuel..What do I look for?..Thanks for any help,Chris.

You probably have hooked up the electrical connections on the fuel pump backwards. It's very easy to get wrong. Try swapping them and see if you get fuel.

[lakes73]

Hi SlowLane,Noob here,Would the pump even run at all if the wires are backwards?....I have the Red on the positive and a tan one on neg.Chris.

[SlowLane]

Yes, it runs fine, just backwards.

Fine, that is, until it heats up and burns out due to not having any fuel passing through it to cool it off.

Just try swapping the wires and see if it makes a difference. It should be quickly obvious if it does.

This is assuming that you have not installed the pump itself backwards. On the Bus/Vanagon pumps, the inlet and outlet are different sizes, so they're virtually impossible to mix up, but I don't know about the Beetle pumps...

[lakes73]

Hey SlowLane,You were right,the wires were backwards,the Red wire is the ground,tan is hot..Now the pump is running,with no strange gurgling sound..But still no fuel back at the engine where I pulled the fuel line off to check right before it goes into the cold start valve..What now?..Thanks,Chris.

[SlowLane]

Here's the Bentley fuel pressure troubleshooting list:

If, after replacing the pump, there is still no fuel pressure, check for the following possible causes:

1. Fuel filter blocked.

• Rust or other foreign matter in fuel tank.

• Defective pressure regulator.

• Wires for fuel pump or fuel pump connections interchanged.

• Hoses interchanged at pump or at pressure regulator.

Check again that you have the inlet and outlet hoses correctly connected to the pump. If you discover that they are reversed, then reconnect them correctly and then change the pump wire connections back to how you had them originally. The photo of the fuel pump and filter in my Beetle Bentley is rather poor in detail, but it looks like the inlet to the pump is on the rounded dome part of the pump at the opposite end from the electrical connectors.

When the pump is running, you should have fuel positively shooting out of the disconnected CSV hose. Be sure to have a good-sized container ready to catch it.

Good luck

[lakes73]

New fuel pump runs...No fuel coming out of the outlet on the pump at all...Fuel Filter is dry as a bone also...The only fuel that was in the line started pouring out when I removed the hose that ran from the outlet from the pump going back to the engine fuel rail..!@#$%^&*!!!!...Chris. P.S.I also used a new fuel filter also.

[Amskeptic]

Hey SlowLane,You were right,the wires were backwards,the Red wire is the ground,tan is hot..Now the pump is running,with no strange gurgling sound..But still no fuel back at the engine where I pulled the fuel line off to check right before it goes into the cold start valve..What now?..Thanks,Chris.

What is this? I see past tense "the wires were backwards", and the present tense used to describe "red wire is the ground" and "tan is hot". This reads like it is NOW backwards.

Can we be specific with our writing here? Actually, I will be specific.
Make sure that the tan wire is grounded and going to (-) on the pump.
Make sure that red/blue is going to 88d and the (+) on the pump.
Make sure you have clear fuel line from tank to filter.
Colin

[SlowLane]

Fuel Filter is dry as a bone also

This points to a problem independent of the pump. The filter sits between the outlet of the tank and the inlet of the pump. So you either have a blockage in the tank which is preventing fuel getting out of the tank, a blockage in the plumbing between the tank and the filter (which includes the filter itself), or you don't have any fuel in the tank. Or some combination of the above. Figure out which.

Given this new information, my former advice about backwards-wired fuel pump isn't worth the paper it's not written on. Suggest you wire it back to how you had it originally, then sort out the reason why fuel isn't getting to your filter.

[lakes73]

OK,I`ll let you know what I find..Thanks again for your info.Chris.

[lakes73]

Re-wired the pump..Red +/Tan -....Pump ran...No fuel coming from outlet..No fuel coming from tank to filter..Removed hose from gas tank..it was clear..Stuck a coat hanger wire into outlet coming out of the tank to see if I could find some kind of blockage..I can only get the wire in 3 or 4 inches before it stops and won`t go in any more..I don`t want to force it..I can`t tell what it is hitting...There is no fuel coming from the outlet..What next? Thanks,Chris..

[RSorak 71Westy]

Try blowing into the tank to see if the line is clear.

[SlowLane]

I don't know about the later Beetle tanks, but the earlier Bay window tanks had a removable outlet pipe screwed onto a bung. They also had a mesh sock on the inside to filter crud out of the fuel before it got into the line. Try to see if your tank has a removable outlet: it would probably look like a hex nut.

Suggest you siphon out as much gas as you can before chasing down the root cause of your blockage. You might be best served at this point to remove the tank from the car. It'll be a lot easier to work on. Just be careful about flammable fumes when the tank is out and empty.

[lakes73]

I replaced my new fuel pump with another new one..The beetle fired right up..Took her for a 20 min. test run,before the rain was to fall,She ran good..Came home,let her sit for 30 min...and she started right back up!..I want to thank all of you Itinerant Air-Cooled folks for all of the help you have given this noob! Chris.

[Amskeptic]

I replaced my new fuel pump with another new one..The beetle fired right up..Took her for a 20 min. test run,before the rain was to fall,She ran good..Came home,let her sit for 30 min...and she started right back up!..I want to thank all of you Itinerant Air-Cooled folks for all of the help you have given this noob! Chris.

Does this mean that the first new fuel pump was defective? If so, what brand and vendor?
Colin
(p.s. I bet you are relieved)