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StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

My car has a fuel problem in which no fuel seems to be going to any cylinders. When I crank the car, it usually backfires out the manifold after a few seconds. The strange thing is, fuel leaks from two fuel lines. One is a fuel return line, and the other is the fuel control line.

Anyway, I went to a german import shop and asked the guy there if he could buy me those lines, and if he had any advice. He said it was most likely the warm up valve. Is this a common problem? He said that the valve is wrather expensive new. If anyone has suggestions or parts, I would like to hear from you

Ryan
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1978 924 NA
-250lb lowering springs, Euro Pistons

Ozzie · Posted: Sun Apr 30, 2006 8:21 am Post subject:

IIRC, you can loosen off the fitting to each injector and see if the injector is getting fuel.
You can even pull the injector and check its spray pattern to see if its blocked.
The WUR wont prevent them from getting fuel.
Check the fuel pumps.
If all seems ok then check spark and timing.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

I am positive I have spark, and I just recently set the timing, correctly. What is the WUR?

Ryan
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1978 924 NA
-250lb lowering springs, Euro Pistons

Ozzie · Posted: Sun Apr 30, 2006 1:13 pm Post subject:

Warm Up Regulator/valve.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

D Hook · Joined: 02 Nov 2002 Posts: 3158 Location: Omaha, NE

Performance products has them for around $90 each, rebuilt.
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'80 924 n/a SOLD

StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

If I do the rebuilt thing, what all do I do? Do I send them my WUR, and $185 or whatever? So I ever get the $100s back? Sounds like a pita.

Ryan
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1978 924 NA
-250lb lowering springs, Euro Pistons

Ozzie · Posted: Sun Apr 30, 2006 6:29 pm Post subject:

The WUR is only used during warming up the car.
When hot it closes off and doesn't (shouldn't) affect the fuel.
Even when cold a faulty WUR will give you trouble idling but wont stop it starting.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Smoothie · Posted: Sun Apr 30, 2006 9:44 pm Post subject:

WUR = "control pressure regulator" or as your mechanic said, "warm up valve".
Actually, it should never close completely. It's opened more when cold to allow the control plunger (and air metering plate) to travel further which enriches the air:fuel mix. It regulates the "control pressure" above the plunger to something in the 20-30 psi range when cold, depending on just how cold it is. After it's warm, it closes some and regulates the control pressure to about 55 psi, leaning it out to the correct mixture for normal warmed-up running.
Some cars, like the 931, use a WUR that has a vacuum-line connection. This version enriches the mix again whenever you're at full throttle, even after warm-up.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

D Hook · Joined: 02 Nov 2002 Posts: 3158 Location: Omaha, NE

Call and order the part. Your out-of-pocket cost is the part plus the core charge. They'll refund the core charge when you send them your REBUILDABLE core. I emphasize that so you don't pull it apart and send it to them in pieces. You may not get your core charge back then.

I've ordered two of these from them and have had no problem getting the core charge back. If you can do it w/a credit card, it'll be easier because they can just issue you a credit on the card and not have to cut you a check, which can delay things.
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'80 924 n/a SOLD

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

It is possible the mechanic meant the cold start valve which could also be causing the problem. Before throwing parts at it, a good diagnosis should be performed.

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

Eturbo924 · Joined: 09 Nov 2002 Posts: 2212 Location: Londonderry NH

Not sure if anyone else said this but the check valve on the fuel pumps can go bad. So the fuel runs back to the tank.... thus no fuel in the lines. It takes some time to get the system back up to pressure and engough fuel at the engine to get the old girl started.

The 1977 that I just purchased has this problem. Interesting thing is that the previous owner also bypassed the fuel pump relay and also put in a push button to fire the cold start valve. So at the moment I turn the key to the run position... let the pump run for about 20 sec... then turn the car over. If there is still not enough fuel... I push the button and give it a quick shot from the cold start valve and it comes to life.

Anyway think about the check valve. Especially if it is real bad after sitting over night.

Eric
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1982 924
1992 968
2003 C4S
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