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Hey guys, i have a 92 GTSt Type M that ive been having some starting issues and after some talking between myself a another mechanic we came to the thought that it may have a stuck open purge valve, alas information is short in english. So why might i have raw gas in this line here?

Its not a lot of gas but enough to be of concern, especially since its infront of the throttlebody?

 

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That hose supplies air from upstream the throttlebody to the idle control valve at the back of the plenum chamber.  If by "raw gas" you mean petrol, then.....WTF?!  There really shouldn't be any liquid petrol just rolling around in the plenum chamber, let alone finding its way back through the ICV and into that hose.

By purge valve, are you talking about the fuel tank breather system?  If so, there should never be liquid fuel in that either, just vapour.  It would have to be dead cold for fuel vapour to recondense in there.

17 minutes ago, GTSBoy said:

That hose supplies air from upstream the throttlebody to the idle control valve at the back of the plenum chamber.  If by "raw gas" you mean petrol, then.....WTF?!  There really shouldn't be any liquid petrol just rolling around in the plenum chamber, let alone finding its way back through the ICV and into that hose.

By purge valve, are you talking about the fuel tank breather system?  If so, there should never be liquid fuel in that either, just vapour.  It would have to be dead cold for fuel vapour to recondense in there.

Well therein lies my problem haha. It was definitely petrol and there was maybe a half teaspoon of petrol in the line. 

Ok after digging through every article i could find,  i found out the line is run to the IACV and an air regulator valve. So there shouldnt be fuel in the line, however there is a small vacuum line that runs to the rear fuel pressure regulator. 

So i think the rear FPR might be going bad and pumping fuel into the lines off the IACV and air regulator

  • 2 months later...

Not sure if anyone was following this but i removed the fuel pressure damper and replaced it with a fuel pressure regulator adaptor and 90° brass fitting and the car now runs 100% again.

The damper ended up having a ton of fuel in the vacuum line and on the wrong side of the diaphragm.

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