Hi all. I have 92 1g dsm awd tsi. My car doesn't start properly. I have to pinch the fuel pressure return line in order to start it. I have changed the fuel pump to an evo 8 ran a new -6an line to the new oem fuel filter, -6an line to the fuel rail and I have swapped out 3 fuel pressure regulators.
All studs have been replaced with rtm stud repair kit. I still have to rewire the fuel pump with the stm kit.
Bow when I unclamp the return line the car starts to stutter and wants to die. The vaccum goes close to 0. And if I give it gas it bogs and sputters. Removing the maf sensor throws a CEL but car starts to run ok but still sputters. And if I give it gas it wants to shut off for a second then runs fine. I've been told that it could be a boost leak or i may not have enough fuel pressure. Please help me. Can anyone help me do a boost leak test. I'm in mississauga. I will pay you for ur time I need this car running as I don't have another car and need to go to work.
Thanks everyone in advance

I would start by searching for a leak, maybe your o ring isn't good or anything between the pump and the rail could be the issue.

The fuel pump is off an evo 8. I used a new fuel pump install kit from ziggy. Got a new 6an line from the fuel pump sending unit to the new oem fuel pump. I doubt that there's a restriction between fuel pump and fuel rail. Pump does need to be rewired with the stm kit.

Is your vacuum line to the regulator plumbed after the throttle body??

Sorry don't really understand what u mean by that. The vaccum line is on the fpr. All vaccum lines on top of the throttle body are cut and blocked.

What shape is the fuel filter in?

It's brand new oem mitsubishi fuel filter

Ok turn the pump on and pinch the line then turn the car off.
If the pressure drops you have a leak.

Mike is asking where the FPR line is coming from. Can you take a picture of everything and post it.

Ok will do..I'll take a pic tomorrow morning. How do I post a pic here. Had a hard time before too.

Picasa works well and photobucket is popular too.

I use photobucket.com

Create an account.

Upload pics from your mobile.

Click on the share icon and copy and paste the [IMG] hyperlink.

Post here.

Alright I definitely will.

There's an app for Android for photobucket. Not sure about Apple..? Gotta be..

I'm guessing bad seal at the fuel pump neck to sending unit.

I suspect something similar. He used one of my repair kits for the studs in the tank and said the bolts were too short. I kept telling him if the bolts are too short, you have done something wrong...

Clamped return line and maf on 70 psi.
Clamped return line no maf 70 psi .
Unclamped returnline maf on 30psi
Unclamped return line maf off 38psi.

Got the fluid filled rtm racing gauge and connected it right before the fuel rail.

What do you mean maf on, maf off?

I mean maf connector plugged in or out.
I disconnected the maf to see if the car would run differently and it did.

Yeah it would cause it goes into limp mode.

See what you pressure is with the vacuum line off of the fuel pressure regular is

I didn't check that. So u want me to take off the vaccum line

Yeah while the car is running and tell me how much fuel pressure, then clamp the return and turn the car off and tell me how much fuel pressure. If it drops tell me how fast it drops.
You will need two people for this, or I guess a camera would work

Ok will post results in a couple of hours. What will this determine tho. I'm thinking that my injectors are bad. Because the fuel that came out of the fuel filter was brown and sludgy full of rust.

Did you clean your tank when you opened it up? you have the sock on the fuel pump?
They may be dirty.
This will determine if your fuel system is at the right pressure, then the pressure drop will tell us if you have a leak before the regulator.

If the fuel that came out of your filter was rusty, that would suggest your problem is before the filter. Its job is to stop that crap from getting to your injectors. However, some may still have gotten there.

Bryan's suggestions would be good next steps: car running with vacuum line off the regulator shows you your base fuel pressure. What fuel pressure regulator are you running?

If you're on a stock regulator and the pressure comes up as being too low, you've got a flow issue in your feed, likely caused by crap getting sucked up in the tank.

Let us know what you find!

I have changed the fuel pump with an evo 8 pump. New install kit with new sock. 6an line to the filter. Fresh gas. New oem fuel filter. The crud and nasty fuel came out of the old fuel filter.
I'm running a stock fuel pressure regulator. I have 3 of them and have tried all of them on.

Yes but if the problem was in your fuel tank, changing all that wouldn't eliminate the problem. How did the old sock look?

Anyway, still think checking base fuel pressure is your next step. If it's low, the fact you've tried 3 means the problem is not likely the regulator.