Problems with the 3.4 TURBO-again

[d.o.h.c]

It does this but it makes a little boost before it happens

http://www.youtube.com/watch?v=HY7NBZvROpM

[d.o.h.c]

checked the line going to the external wastegate and its ok

[1988GTU]

So the a/f ratio is fine? Not lean or anything abnormal?
I personally think the wastegate crapped out or is getting weak.

What are the specs or your setup? Is the tC non internal gated or did you use a internal gated tc and jam the flap shut? If you can, pull off the wastegate, cap the pipe and test the car then. DONT rag on it, and if it builds boost... well there's your answer.

[d.o.h.c]

well the gauge at less then 3 psi is green then once it hits 3psi it goes all over the place. Its not like it stays at 3 psi, it gets to 3 psi and kills the rpm and it feels like the car is surging

[d.o.h.c]

thats very dangerous to do. The waste gate is a tial, with a 7 psi spring. I really doubt that its that, if it was the wastegate it would vent the boost not surge it right? The turbo is a brand new garrett with an external turbine side so no flap, just straight out.

[d.o.h.c]

What I can do is disconnect the vacuum line to the wastegate. If it boost past 3 psi then that is the problem, but I doubt it. I think that is is the fuel.

[timg]

It really sounds like a fueling issue. Do you have any way to watch a fuel pressure gauge while it begins to boost?

Are you still on the stock fuel pump?

If you're having trouble, a decent shop with a chassis dyno should be able to troubleshoot and fix your problem within an hour or two with basic tools (scan tool, fuel pressure gauge, a/f ratio, etc).

Tim

[timg]

One more question.

How is your normal FPR? Does it leak fuel from the vacuum feed, or is it ok?

Tim

[d.o.h.c]

I called vortech they told me how to test the fmu with the car running. Basically take the plate off on top and push down on the diaphram and the fuel should psi should go up. I have a walbro 255 pump. As far as the FPR, is there anywya to tell from the end of the vacuum line. I dont want to have to take the plenum off

[d.o.h.c]

what will the FPR do?

[1988GTU]

Do a couple fuel pressure tests.

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I was just trying to find something until you maybe located a gauge to test the fuel pressures. Why can't you disconnect the vacuum line sourced to the stock fpr at the tb?

[mrsleeve91]

From the vid sounds like its spooling, did you check the bolw off / intake pipe conections?


or the external gate is not sealing shut....

Alan

[d.o.h.c]

I did take the wastegate off, I will have to double check that. The vacuum line that runs to the FPR on the 3.4 dohc is under the plenum. I dont want to take it off unless I knoe for sure that is the problem. I can disconnect it at the port on the side of the plenum and see what that does. I will have to check everything over and see if I cant find a loose connection.

[d.o.h.c]

Ok I checked the fuel pressure and all good. I took the FMU apart and it works as well. So what should I do next? I did look at the wastegate and it looks good, vacuum hose is hooked up so.

[d.o.h.c]

http://s169.photobucket.com/albums/u230/dohcv6/?action=view&current=10-30-07_1031.flv