Hey guys/girls, my car is running like crap, I've had the motor out and apart so there's every chance something isn't put back correctly. I checked the fuel pressure going into the rail, it's reading 3bar(1 bar too much). I pulled the vacuum line off the pressure regulator and it has no vacuum going to it. The line is coming from what looks like an electronically controlled vacuum switch mounted on the plenum. Can anyone offer any advise? Thanks.

Oh yeah, forgot to say it's turbo. Standard pressure regulator.

I think the solenoid your talking about raises fuel pressure to help start the car easily when it's hot. So maybe you have the vacuum hoses on the wrong ports of the solenoid? There is also a one-way valve in there somewhere, which if hooked up wrong could explain why vacuum is not seen at the regulator. Somebody may have a diagram?

by adding engine vacuum to the pressure reg your only gonna pull the pressure down in accordance to the engine vacuum. the fuel pressure is always changing depending on engine vacuum. you may have the vacuum lines the wrong way round but if u still got no vacuum you will have to check the sensor itself will will take too long to explain. or for a quick fix you can just put a T-peice into another vacuum source and away u go

Yeah a diagram or something would be pretty useful, there's so many vacuum lines in there it's pretty hard to remember where they all came from. I thought about running vacuum off another source to get it running properly, but would still rather try to fix it properly as I'm sure there's a reason for that solenoid to be there. Might just try switching a few things round and see if I can get it right.

i think its called the "fuel pressure regulator solenoid valve" and yeah it's made to stop vacume decreasing th fuel pressure when the ingine decides, ie stine cold or hot start. just by pass it, run one of the small rubber hoses from the plenum streight on to the plenum, if this fixes it then you know its a problem, then figure out which pipes go on what. or another way to test it is to take the pipe of the plenum of, the pipe of the regulator of and blow into the plenum end, with the car turned of you should be able to blow air through it, and if you want you can test the solenoid, it should show an impodence of 35ohms, i think, and if you supply power to it it should stop air going through it, make sure you run neg/pos correctly though or you could blow a diode in it. hmm, after all that i dont think this is your problem, if you solenoid valvle was hooked up wrong then the fuel regulator would always have the same pressure, causing the engine to possible run rich at cruise, and definatley lean under power, being lean it would probably pop and sound like its backfiring, you did not mention this so i doubt air getting through the s/valve is a problem.

I have pictures on my other computer, I'll post them up this afternoon if you haven't already figured it out.

I got a mate from work to draw a diagram as he's got a VLT sitting at home. What he gave me says the vacuum lines run from: -Manifold to T piece,one side of the T piece to the front of the solenoid, the other side to the surge tank via a one way valve. -From the rear most connection on the solenoid to the surge tank -From the middle connection on the solenoid to the pressure regulator Does this sound right? This is the way I had it set up before, I put a vacuum line straight from the manifold to the pressure regulator to check it and it still runs the same. Idle's O.K but won't rev at all. Still has 3 bar of pressure in the rail, doesn't change much when revving it.

man the only thing that controls pressure is the reg so id be trying a new reg or before you do that. take off your fuel cap and return line and see if you can blow through it freely. if not theres a blockage or a pinch somewhere along the line. if not id be swapping regs with a mate