Viggen only making 3 pounds of boost! :(

[SkyWarp]

My 2000 Viggen is really slow! When i bought the car it was only making base boost. I installed a boost gauge not to long ago and it was reading about 6.5 pounds of boost. I had my ECU tuned to stage 2 and had the SID info displayed. After that it makes even less boost, only about 3 pounds max in every gear. I tried a different MAF no change. I changed all the vac lines and also did that vac mod that nick from GS recommends. Other than the low boost the car runs fine. I removed the W hose and no change, also plugged up the R hose and no change. Could it be a clogged cat? or a major boost leak?

Rob

[losacker]

i would check your diverter valve. i was only getting about 5psi then switched to a BOV(yours has to recirculate) and that was the issue. it could be boost leaks but i would think it would still boost more than 3psi even with that. also base boost on my car is 10.5psi so it seems like soemting hasnt been correct for a while. check the wastegate and see if it is a little hard to move the rod or if it moves freely. if it moves freely, then the wastegate is bad. good luck! trying to figure out low boost is a PITA

[SkyWarp]

Diverter Valve is good i changed it not to long ago. The wastegate is also in proper working order. I put a cat back exhaust so thats not the problem either. Car runs great its just not making any boost. New plugs and air filter and i also changed the fuel filter, but your right what a PITA!

[condaddy]

I think if it doesn't boost good with W hose off I think it has something to do with your turbo

[Fox Fader]

If it were leaking I'd think you'd be able to hear it. At least I could hear mine.

You're either up against a boost leak or a turbo problem.

How's the air filter and intake hose?

[SkyWarp]

The air filter is brand new and the intake hose seems fine also. You guys think it might be a clogged cat?

[SkyWarp]

Im learning how to read the open SID. Its pretty neat to see how it works

[Shirozina]

Like has been said - if you remove the hose to the actuator and it still doesn't boost then you have a broken turbo or a blocked exhaust. I've seen this problem before and it was a partialy melted cat. What sometimes happens is that when the DIC starts to fail it misfires and unburnt fuel gets into the cat which then burns there and melts the cat. One way to check is to loosen off the exhaust at the DP to turbo flange so there is a about a 1/2" gap and go for a drive - it will be loud and the engine may throw a CEL as the O2 sensor will read wrong but if it boosts you have found your problem. The other thing to check is the ECM value in open SID - this code relates to what limiter is active in the ecu that is restricting power. There are lists published on various sites as to what each number means. BTW - has the DIC been replaced as if it's fauty the symptoms show under boost as it's harder to ignite the mixture. Also check the SID value Fcod as this is the fault code stored and should say if it's misfiring.

[SkyWarp]

Originally Posted by Shirozina

Like has been said - if you remove the hose to the actuator and it still doesn't boost then you have a broken turbo or a blocked exhaust. I've seen this problem before and it was a partialy melted cat. What sometimes happens is that when the DIC starts to fail it misfires and unburnt fuel gets into the cat which then burns there and melts the cat. One way to check is to loosen off the exhaust at the DP to turbo flange so there is a about a 1/2" gap and go for a drive - it will be loud and the engine may throw a CEL as the O2 sensor will read wrong but if it boosts you have found your problem. The other thing to check is the ECM value in open SID - this code relates to what limiter is active in the ecu that is restricting power. There are lists published on various sites as to what each number means. BTW - has the DIC been replaced as if it's fauty the symptoms show under boost as it's harder to ignite the mixture. Also check the SID value Fcod as this is the fault code stored and should say if it's misfiring.

Thank you very much! i will def check all these things!