I am Stumped. Video Inside

[EIPtuningR32]

Okay, so I have always thought i had a bad fuel accumulator. Well, i bypassed the accumulator and and still no start. I disconnected the fuel line going to the farthest cylinder from the passenger side (its been so long since i have worked on the car i forgot whats what.) There was no fuel coming out of that line. So i took the fuel pump off and tested that. It was in good working order. So I then took off the fuel feed line to what I am pretty sure is the warm up regulator and attempted to start the car to see if there was flow.... to my surprise, the car started right up. Fuel was flowing out of the line i disconnected. I then reconnected the line and started the car again and it would kind of run for a little while then it was die off and crank endlessly like it was doing beforehand. Any ideas why the car runs with the fuel line disconnected but does not run with it connected?

Here is a picture of the fuel accumulator bypass:


I disconnected this fuel line and nothing came out:


Here is the video. I turned off the car when the fuel line was disconnected. Something about running the car without fuel =/

http://s573.beta.photobucket.com/user/EIPtuningR32/media/VIDEO0002_zps0873212f.mp4.html

[Maleficio]

Fuel pressure dying off with regulator connected. Flow sounds like it's being routed back to the tank instead of pressurizing injectors.

[EIPtuningR32]

So what should I do? New WUR?

[Maleficio]

I have zero experience with your fuel system. It just sounds like that's what's happening.

[Maleficio]

But I'd say you've located the source of your problem.

[EIPtuningR32]

Yeah, I think the warm up regulator is the culprit, but I would: a) like to make sure b) like to understand what's going on.

[Maleficio]

Porsche 928 Forums dot com - View topic - CIS Warm Up Regulator Made Simple

[BoiseShark]

How long will it run with that line undone? I'll check tomorrow on my car, but I'm pretty sure that line runs back to the top of your fuel distributor to simply control pressure there...it's kind of a back flow thing going on. fuel runs into the WUR and then it allows a certain amount of pressure back to the distributor through that line you took off which controls the plung of the plunger to mix proper fuel to air at the distributor. It is not the gas intake, it is simply a fuel operated pressure valve if that makes any sense.

I would agree that the WUR is sending out the wrong pressure. Put a pressure guage on it and you will know right away.

[MPDano]

My Video when I installed a brand new WUR from 928 Motorsports. Although it smoothed it up a bit, my real problem was my Heads being a US port and running Euro CIS. It created a huge vacuum leak upon acceleration. Once I removed the use of the Diverter Valve, it no longer had that vac leak. Also, passed smog without it as well. The new cats really clean it up without pumping air into the cats. In a nutshell, I have a good used WUR but not willing to just give away. I'd sell it for 1/2 the going rate for a used one. First, I can also make a video of it running on my car. Then we know it's good when it left here.

[rjm65]

I would start off with the easiest thing to check. Jumper the fuel pump, adjust the mixture screw until you hear the fuel injectors start to buzz, then back off just enough so the buzz stops. When the injectors are buzzing, they are actually flowing fuel into the cylinders, so you want to be quick about it, don't want to run the risk of hydrolock.

Now try to start the car.

When you disconnected the line at the WUR, you eliminated control pressure. Lower control pressure = richer mixture.

If you don't have a long allen wrench to reach through the airbox to adjust the mixture screw, remove the airbox for easier access.

If the car doesn't start, then you at least know you have your baseline mixture where it needs to be and now need to hook up a set of pressure gauges to further diagnose.

[BoiseShark]

Yep, do that!

[EIPtuningR32]

Originally Posted by rjm65

I would start off with the easiest thing to check. Jumper the fuel pump, adjust the mixture screw until you hear the fuel injectors start to buzz, then back off just enough so the buzz stops. When the injectors are buzzing, they are actually flowing fuel into the cylinders, so you want to be quick about it, don't want to run the risk of hydrolock.

Now try to start the car.

When you disconnected the line at the WUR, you eliminated control pressure. Lower control pressure = richer mixture.

If you don't have a long allen wrench to reach through the airbox to adjust the mixture screw, remove the airbox for easier access.

If the car doesn't start, then you at least know you have your baseline mixture where it needs to be and now need to hook up a set of pressure gauges to further diagnose.

I'll give this a shot tomorrow sometime and post up the results with video. Thanks for the help peeps.

[AirtekHVAC]

Start adjustment clockwise,. or counter....

[rjm65]

Clockwise to richen until the injectors start to buzz, then counter-clockwise until they stop.

[EIPtuningR32]

sorry guys, its been raining like no other here in Florida. It should be sunny tomorrow. I'll try and get at it after court. =/