1984 GTI Rabbit Fuel Pressure Problem

Hello

I have a 1984 GTi Rabbit.

For the past month or so the car is difficult to start after it sits an hour
or more. What happens is that the car starts right away and then dies after
5 seconds or so. It will start right up again and then after a few seconds
die. If I start it with my foot on the pedal and have it rev at 2000rpm and
hold it there for 1 minute I can release the pedal and the car will run
fine. I can start and stop it fine, if the car sits for more then about an
hour I am back to the problem. Temperature doesn't seem to affect it.

I think I am losing fuel pressure. I went to change the fuel filter in the
morning after the car sat overnight. When I went to loosen the banjo bolt
on the output side of the fuel filter the fuel didn't spray as I loosened
the banjo bolt. This tells me that the system was not under pressure. I
noticed that the output side banjo bolt has a little spring in it is this a
check valve?

Now I have to narrow down where am I losing pressure: fuel accumulator?
Leaky injectors? Cold start valve?

Is there a way to narrow down and divide the system? If there was no
pressure at the fuel filter does that mean that the leak could be before or
after the fuel distributor?

About a week ago I pulled the car into the driveway, the car was cold but
the fuel system was under pressure. I had a spare warm up pressure
regulator so I decided to swap it. When I went to loosen the lines at the
warm up pressure regulator the fuel was under pressure and gas sprayed out
as expected. I did however notice when I put the spare fuel accumulator in
that the car started up pretty much right away. I am just trying to use
this in my troubleshooting logic, that the fuel pressure got back up pretty
fast after losing pressure at the warm-up regulator.


This is what I think is going on:

My fuel accumulator is leaky. And after it sits for a while, fuel pressure
drops as fuel goes back into the tank. However there is fuel pressure up on
the fuel distributor side that is why the car starts right away, but then
dies as the fuel pump has the bring the capacity of the system back up as
pressure has dropped from the accumulator to the fuel filter / fuel
distributor input.

sorry for the rambling.

Any ideas?

On Mon, 04 Jun 2007 16:20:05 GMT, "Tube Audio" <murphysf DeleteThis @hotmail.com>
wrote:

>Hello
>
>I have a 1984 GTi Rabbit.
>
>For the past month or so the car is difficult to start after it sits an hour
>or more. What happens is that the car starts right away and then dies after
>5 seconds or so. It will start right up again and then after a few seconds
>die. If I start it with my foot on the pedal and have it rev at 2000rpm and
>hold it there for 1 minute I can release the pedal and the car will run
>fine. I can start and stop it fine, if the car sits for more then about an
>hour I am back to the problem. Temperature doesn't seem to affect it.
>
>I think I am losing fuel pressure. I went to change the fuel filter in the
>morning after the car sat overnight. When I went to loosen the banjo bolt
>on the output side of the fuel filter the fuel didn't spray as I loosened
>the banjo bolt. This tells me that the system was not under pressure. I
>noticed that the output side banjo bolt has a little spring in it is this a
>check valve?
>
>Now I have to narrow down where am I losing pressure: fuel accumulator?
>Leaky injectors? Cold start valve?
>
>Is there a way to narrow down and divide the system? If there was no
>pressure at the fuel filter does that mean that the leak could be before or
>after the fuel distributor?
>
>About a week ago I pulled the car into the driveway, the car was cold but
>the fuel system was under pressure. I had a spare warm up pressure
>regulator so I decided to swap it. When I went to loosen the lines at the
>warm up pressure regulator the fuel was under pressure and gas sprayed out
>as expected. I did however notice when I put the spare fuel accumulator in
>that the car started up pretty much right away. I am just trying to use
>this in my troubleshooting logic, that the fuel pressure got back up pretty
>fast after losing pressure at the warm-up regulator.
>
>
>This is what I think is going on:
>
>My fuel accumulator is leaky. And after it sits for a while, fuel pressure
>drops as fuel goes back into the tank. However there is fuel pressure up on
>the fuel distributor side that is why the car starts right away, but then
>dies as the fuel pump has the bring the capacity of the system back up as
>pressure has dropped from the accumulator to the fuel filter / fuel
>distributor input.
>
>sorry for the rambling.
>
>Any ideas?
>
Leaks can be anywhere and they can be multiple.

I think if the pressure accumulator was bad you would see fuel under
the car. The accumulator is actually a surge device next to the fuel
pump. It also does have bit of gas stored to prevent vapor lock. I
have not had one fail but I only had 300,000 miles on one Rabbit and
about the same on the second. Do the injectors drip when you do the
drip test? Have you changed the fuel distributor? Not a part many have
laying around in their spare parts pile. How do you know the cpr you
swapped is good without a pressure guage?

My problems were related to a bad control pressure regulator one time.
Bad fuel distributor another time. Bad fuel pump relay another time.
Probably leaky injectors but I tended to replace those at regular
intervals.

It costs lots of money to guess without a pressure guage and a fused
jumper wire.. Of course a good repair manual helps you use the
pressure guage.