Where is my fuel?

seacook · Post by **seacook** » Sat Sep 24, 2005 2:45 pm

What a drag, I tried to go home at quitin' time on wendsday and my engine would crank but not start. I found no power to the transfer fuel pump in the tank so I looked at the fuel relay. It was not a pretty sight. Even though I work for a Vw Dealer thay did not have a relay for my car in stock. Guess 1984 really IS history. One of the parts guys call up B.A.P. Even though B.A.P. had it I couldnt get it untill the next day....so in the end I pulled a simular relay from an alarm system and used it to get me home. Thankfully I did not miss that episode of LOST. Now this weekend I changed out the relay with the correct one and took the car for a spin. It was then that I noticed the power loss. Then it died...hmmm....Seems like even more of a fuel issue. My in-tank fuel pumps performace was lacking. I changed the pump out and while I was at it also changed the air filter and Fuel filter. The fuel that poored out of the fuel filter was a disgusting black tinted muck. Now after charging the battery back up, I got her to run again. But it took considerable effort due to lack of fuel in the lines.The power still seems substandard but at least its a running rabbit.

Post by **SoCal_Cabby** » Sat Sep 24, 2005 2:55 pm

if your tranfer pump was toasted its just a matter of time that your main pump goes out, from being over worked to make up for the tranfer pump not doing its job, so plan on getting a main pump soon so you're not in the same predicament again

CalAltaDubber · Post by **CalAltaDubber** » Sat Sep 24, 2005 5:47 pm

Because you said tat the fuel comming from the fuel lines was "black" I strongly suggest draining the fuel tank, cleaning it out and replace your fuel filter.

I've had this problem before and you will find that it is the only way to prevent other problems from arising.

Post by **Briano1234** » Sat Sep 24, 2005 9:54 pm

I second that and would like to add that your rubber hoses are probably going south, black colored fuel would indicate to me that your rubber is lost and is being etched by the gas.

Why does a transfer pump do and what are the indication of it dying?

A Transfer pump does just what it says it does. It transfers fuel out of the tank and into the Primary pump. The primary pump is designed so that it dosen't have the great suction power that the transfer pump has and depend on the transfer pump to supply it with fuel. The Main pump has the hi-pressure that fuel injection requires.

If the transfer pump is bad, the pump itself become a restriction to fuel flow and can cause the main pump to go out. Indications of this are an abnormally long start cycle, and it groaning under the strain of trying to suck fuel, loss of power, fuel starvation issues.

Fuel Pumps (electric) uses fuel to lubricate the pump, and cool the motor.
This is why when you run your car less that 1/4 of a tank or on empty, and usually run it on empty the motors on the transfer pump weaken, become sticky, or stop running. This is also why your car runs fine for about 20 minutes, then the motor over heats and becomes flakey as in loss of power.

The external pump uses air flowing around it to keep it cool. As Gas in the Tank can warm up in the sun and driving down the road from heat transfering from the exhaust a weak Transfer Pump will overheat.

I always wondered why on my in-tank pumps they always crapped out only when I had a full tank.

Practicle demonstration of a working Fuel system:

Tools / Parts needed:
2 large bowls (fill one with water)
1 Turkey baster bulb removed
1 stop watch
1 plastic coffee stirrer/sipper

Place the turkey baster in the bowl filled with water and using it as a straw siphon out as much water as you can in 3 seconds. Place this amount in to the empty bowl.

Now looking at the former empty bowl you know know how much fuel you can raise in 3 seconds un restricted.

Now try to suck the partially filled bowl empty of water in 3 seconds using only the coffee stirrer..

This shoudl have graphically shown you why the main pump whines so loudly when the transfer pump goes out.

CalAltaDubber · Post by **CalAltaDubber** » Sun Sep 25, 2005 9:54 pm

Good explaination Brian.

CalAltaDubber · Post by **CalAltaDubber** » Fri Sep 30, 2005 10:11 pm

Hey Seacook,

How did you make out with this problem?

seacook · Post by **seacook** » Fri Sep 30, 2005 11:20 pm

The rabbit is in running condition however I have not yet put it through a long distance trip after the pump replacement. This weekend I probably will after I adjust the airflow a little. Right now its burning too rich. Yesterday I installed the missing bushing/insert that goes between the cable/hook & the gas pedal hole. Complete throttle control ....
what a rush!

CalAltaDubber · Post by **CalAltaDubber** » Sat Oct 01, 2005 5:00 pm

seacook wrote:Yesterday I installed the missing bushing/insert that goes between the cable/hook & the gas pedal hole. Complete throttle control ....
what a rush!

Been there. Was on a cruise when the cable pulled out of the bushing.

Now I carry a spare in the ashtray