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TURBO 3.4DOHC PROBLEMS-WTF NO FMU


dohc v6

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OK so my car ran great and I need to do some things to it, like ball joints, tie rods, front breaks,ect. So I did everything encluding the a/c compressor and lines. I also did change my 3psi spring to a 7 psi spring in the wastgate. I brought it up to the dealer ship and had a 4 wheel alignment and a/c charge and when I got it back it ran good not under boost though. So I go to give it boost and I get to 3 psi and it hits a rev limiter of some sort. I had this same problem with it no boosting before and it was the FMU vacuum line. But I checked everything, FMU fule lines, FMU vacuum lines, all good. So I am asking what would cause the car not to boost past 3 psi. Any help is well appreciated becasue right now when I give it gas it starts to pull and then it just hits a stop.

 

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gapping of the plugs makes a big difference. and yes it could cause this problem cause if the gap is too big it wont have enough of a spark to ignite everything that your trying to by boosting.

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yeah i would say a good place to start is the plugs. get rid of the platinums and go for standards, you changed the spring so you changed and increased the quality and pressure of the boost.

 

I would say at least .30 maybe lower just like was said. Just because you have spark doesnt always mean its strong enough to run it hard.

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well I just drove the car with the fuel pressure gauge hooked up and it went to 80 psi and then dropped. I guess I can go ahead and try gapping the fronts to .25 and then if it seems to work better then I will go ahead and do the back.

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well I just drove the car with the fuel pressure gauge hooked up and it went to 80 psi and then dropped. I guess I can go ahead and try gapping the fronts to .25 and then if it seems to work better then I will go ahead and do the back.

 

Gapping them to .025" may work better. :wink: :biggrin:

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I replaced the FPR and still doing its thing. SO I did a boost leak test. But I have a couple questions. First once I started to pump the IC full of air I heard the wastegate leaking. So I disconnected the vacuum line and pluged the hole on the IC pipe, now I hear a leak at the throttle body almost like its the shaft, but I am not sure. Should the system be pressureized and for how long. I can pump the pump and the air deffinitly leaks right out.

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Well I just took the wastegate off and what do ya know, the vacuum line going to the W/G was melted, I mean melted. So I am going to fix it tonight and take it for a ride. I am 90% sure this is the problem but ya never know.

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I really think you should re-gap ALL 6 plugs. I wouldn't be surprised is this is your issue. .045 might work well enough for the stock NA motor, but it is WAY too big for a Boosted motor. re-gap and I bet your issue goes away

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well the vacuum line was melted to the wastegate again. I just put it on last night and drove 10 minutes. I will replace this and reroute it and seem, if not then I will do the regapping. But they are already at .35 soo. I can not believe silicone vacuum hose could melt so fsat.

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