A little background first:

Newly installed mild street ported motor
New PFC/Commander/Datalogit & WBO2
w/ boost set to .75 50% & seq boost control off
Non-Sequential Stock Twins
All the bolt-on's
Home depot Needle Valve boost controller

Here's the problem:

I can't seem to be able to adjust my boost to a level between 8 psi or totally uncontrolled overboost(15-16 psi before I let off)

No matter how I adjust the needle valve, I either get 8 psi or massive Overboost, and I have to let off. I'm thinking that a signal isn't getting set to the waste-gate solenoid or something. Hell, I don't know. I just know that I can't get the car to hold 12 psi. I used to be able to dial in 13 psi when I had my old stock ported motor w/ an M2 Stage 3 EC and the same HD needle valve.

I've tried switching the solenoid plugs behind the vacuum chamber. That didn't work.

Does anybody know what is going on here? How can I fix this? I'd like to be able to turn up my boost(12-14 psi) an tune my AfR's with my WB. Then I'd like to get some professional help and go for some dyno tuning to dial in my timing.

TIA,

John

 

what dose your boost pattern look like VS rpm?

 

When I first put my avc-r, it shot upto 21lbs of boost.. crazy.. I thought my engine was gone..

I finally realized the cheap silicone hose has melted, by the wastegate actuator..

But by what you say, either 8lbs or 16+lbs.. I would say your home depot controller is messed up..

check your lines and pressure test your depot controller (make sure it opens up at pressure you set)..

 

Just to make sure.. did you set your PFC to non-seq mode??

 

I hit max boost by 3600-3800 rpm. 8psi or it shoots to way over 15 psi. This is dependant in how I set the needle valve.

Quote:

Just to make sure.. did you set your PFC to non-seq mode??

I've tried both Seq. Boost control on and off. The wastegate actuator doesn't seem to be getting a signal to open or close. However, the PFC does activate FUEL CUT when I overboost .25 over the PFC boost setting. I guess that's a good thing.

Quote:

I finally realized the cheap silicone hose has melted, by the wastegate actuator..

This isn't the problem with mine. My hoses are intact.

Quote:

But by what you say, either 8lbs or 16+lbs.. I would say your home depot controller is messed up..

I've tried three different needle valves. Same result. Thanks for replying. Anymore ideas or advice?

 

Your wastegate itself could be sticking.

Let me ask you, does your overboost happen at an exact RPMS every time?

Let me give u a little short story.

My PFC shorted out a few months ago and filled my motor with fuel, fouling my plugs beyond belief. I had to send my ECU to get fixed ( where it is currently) and RIght now im running the stock ecu with no air pump and cut wires. Let me tell ya, it runs rich as crap. So my plugs are still fouled to hell.

I borrowed my friends ecu and went out to test drive to see how my car would run. For some reason every time in third gear at exactly 7k rpms, it would go from 11psi to 17.8 psi faster then you could blink.

I called Steve Kan because I was confused, and he expalined to me that because of my fouled plugs, at that RPMS it could be basically not firing and all the fuel goes directly out the exhaust port, detonates basically at the exhaust turbine and spins up the compressors instantly causing a boost spike.

When was the last time u changed your plugs? Just somthing that could POSSIBLY cause that.

 

Nope, that sounds like an entirely different problem. I used to be able to dial-up the boost by simply by closing the valve off more, restricting the flow throught the vacuum line. Now, It seems react like its either fully open or fully closed.

 

Did you block off the line that tells the ecu to control the wastegate. The line goes from the wastegate area to the engine. I wish I had a camera to take pics to help explain it better.

R.K.

 

I wish I knew what you were describing, too. My car has been this way since I got it back from having a motor installed. It IS very possible that they may have made a mistake in putting my car back together....

My Non-Seq system was done the Rikki(po' man's way)

 

I believe its the orange line on this diagram. There is just a 4" rubber hose in between those two hard lines and all you do is pull it off and cap the ends.


R.K.

 

I know that the nipple on the wastegate is capped. I'm not so sure about the other end. I'll have to check that. Thanks

 

try bypassing your MBC and just run those two lines together. You should get a steady 8 PSI . if not , it somthing else then the boost controller.