How to connect a fuel pressure gauge to 1978 fuel injection engine.

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dennisvwman
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How to connect a fuel pressure gauge to 1978 fuel injection engine.

Post by dennisvwman » Mon May 22, 2017 12:42 pm

I have a 1978 fuel injection super beetle convertible. I have been trying to get it started for the past several weeks.
I have the fuel injection trouble shooting guide and several other pieces of documentation on how to test fuel injection
parts and how to get your car started, but I have had no success. I do not think there is any gas getting to the engine.
I have replaced most, if not all of the fuel injection parts so they are fairly new. I have to test the fuel pump to see
if the engine is getting gas or if there is any fuel pressure. I have a fuel pressure gauge and tried to follow how to install
it but it is not clear.

Is there anyone who knows how to do this?

Thanks.

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panel
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Re: How to connect a fuel pressure gauge to 1978 fuel injection engine.

Post by panel » Tue May 23, 2017 4:48 pm

Can you bypass how the fuel pump is triggered and just run a remote toggle switch to it so you can manually turn it on and off ?

dennisvwman
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Re: How to connect a fuel pressure gauge to 1978 fuel injection engine.

Post by dennisvwman » Wed May 24, 2017 11:42 am

The orange VW Bentley book shows what looks like the fuel line disconnected from the cold start valve and the fuel
pressure line connected to that fuel line. Other documentation explains this and also disconnecting the vacuum line
from the fuel pressure gauge, then remote starting the engine for a few seconds to get a reading. This sounds like
several steps you have to do in order to check if there is any fuel pressure.

Any thoughts on this?

Thanks

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kangaboy
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Re: How to connect a fuel pressure gauge to 1978 fuel injection engine.

Post by kangaboy » Wed May 24, 2017 2:56 pm

Simplest way is to just take the hose from the left fuel rail going to the cold start valve and put the end of the line in a soda bottle. Crank the motor for 10 seconds. If no fuel, then you have a variety of things to look at next (clogged lines, bad fuel pump, clogged filter, rusty fuel tank, etc.).
I would test the leads at the fuel pump as well. Make sure its getting 12v and has a good ground.
As far as the pressure gauge, do you have the fuel rail with a 7mm access port on it? My bus has one of them, and I can just take the nut off and put a line on that for fuel pressure. The only real reason to look at fuel pressure on a stock bug would be for diagnostic purposes...as in, I wouldn't leave it on there full time. First, do some variation of what I mentioned above and see if there is any fuel getting to your motor from you gas tank.
'74 Standard- 1776T, MS3X3
'76 Westy- Stock 2.0L L-Jet

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Dale M.
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Re: How to connect a fuel pressure gauge to 1978 fuel injection engine.

Post by Dale M. » Thu May 25, 2017 8:12 am

I don know it VW did it, but may later cars with EFI have Schrade valve in system to actually hook pressure gauge into system for testing....

IF no test port... Remove line from pump to fuel rail and put in "tee" fitting, connect pressure gauge into "tee" fitting... IF you do not want to leave gauge in place, remove gauge and put plug in place and keep tee in place for possible future testing...

Dale
Lives his life vicariously through his own self.
1970 "Kellison Sand Piper Roadster"

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