Fuel rail pressure measuring valve

[Pink_Floyd]

Half way along the fuel rail on the drivers side is a valve that allows you to measure the fuel pressure. As part of the referb I removed it, it was only screwed in a couple of turns. It looks like it might be tapered. Well on replacing it, it leaks fuel from the thread. Is the right thing fitted? do I need to add some sealent to the threads? Again I can only put it in a couple of turns.

[cogrog]

I Would be interested in the answer to this question as i want to depressurise my fuel system to replace some of my fuel lines, this seems to be the ideal place to dump fuel pessure.

[Pink_Floyd]

cogrog said:

I Would be interested in the answer to this question as i want to depressurise my fuel system to replace some of my fuel lines, this seems to be the ideal place to dump fuel pessure.

Yes you can use this, although I would remove the fuel pump relay and run the engine till it stop to remove the pressure. Using the valve thing may spray fuel over the engine.

[blitzracing]

Never had a problem refitting one, just nick it up. You can de-pressurise the fuel rail by undoing the valve slowly, and holding a rag around the top of the valve as you do to catch the fuel. Not for hot engines however.

[Pink_Floyd]

The thing is, it only goes in a couple of turns, almost like one thread is M10 fine and the other is 3/8 fine. Not been able to find any reference to it on the web.
Here is a pic, this is done up as tight as I want to as any tighter and I think something will go.

Edited by Pink_Floyd on Monday 7th May 11:20

[Pink_Floyd]

pic added.

[Simon says]

By default they do have a sealer around the threads but that should screw in a lot further than a few turns, are you sure your chroming the fuel rail as not built up the threads thus reduced the diameter? reason why I have mentioned this is that I have recently removed this very valve to clean the fuel rail and had no problems like yours

[Pink_Floyd]

Simon says said:

By default they do have a sealer around the threads but that should screw in a lot further than a few turns, are you sure your chroming the fuel rail as not built up the threads thus reduced the diameter? reason why I have mentioned this is that I have recently removed this very valve to clean the fuel rail and had no problems like yours

It was like it before I had it chromed. That is why I think that it could have the wrong thread, But I can't find any reference to what the correct thread should be.

[Simon says]

Pink_Floyd said:

Simon says said:

By default they do have a sealer around the threads but that should screw in a lot further than a few turns, are you sure your chroming the fuel rail as not built up the threads thus reduced the diameter? reason why I have mentioned this is that I have recently removed this very valve to clean the fuel rail and had no problems like yours

It was like it before I had it chromed. That is why I think that it could have the wrong thread, But I can't find any reference to what the correct thread should be.

Are you sure your not being a bit light handed with it as its on a taper thread so as you start to screw it in you have to screw beyond the resistance you will feel but obviously in moderation and with a thread sealer applied I just used Loctite thread seal. Def worth checking the threads match though as who knows the past history of these cars at times