I finally have a chance to disassemble my turbo and find out what cause the chattering noise when the turbo start to build up pressure. I check both primary and secondary turbo and they looks good with minimal shaft play. Then I look at the Turbo Control flapper and it is very loose. Is the Turbo Control flapper suppose to be that loose (please see photos). I can use my hand and pull it in and out, side to side and rotate it a little.

Thanks

BC

 

Yes it is supposed to move. What does the noise sound like?

 

any update?

 

When turbo build up boost, i heard chattering noise from the turbo area. My PFC cut off fuel because it see huge knock # and the engine will not rev up. When i press on the throttle easy, the engine can rev up to high RPM with no boost without problem. I test the car with stock ECU and i can still hear the turbo grinding/chattering noise. So I suspect I have a bad secondary turbo that is grinding when it start to spin, however the both turbo looks ok when I took it apart this morning.

I know some one has the same problem like me. What could be wrong and please help.

Thanks.

BC

 

Any help please?

Thanks

 

Hi All:

Today, I have time to work on the car and suddenly thought of pulling the HKS Twin Power off the car and do some test drive.

Bingo! My car is running good once again after sitting in the garage for months.

My car has been having problem cutting fuel at around 3K rpm under boost. I thought my turbo was grinding the housing which cause chattering noise and trigger the knock sensor to cut fuel and ignition. I check almost everything in my car, turbo, engine code, turbo control solenoids and still can't fix it.

I can not think of the HKS Twin Power went bad because I hardly drive my car. Maybe the engine heat caused it to break down. I am running PFC and tuned at 14psi max 2 years ago and only put around 5000k miles after the tuning.

Have anyone had their Twin Power went bad? Will PFC tuning cause any damage to the Twin Power?

BC-FD3S

 

I don't even know if you're talking about the same problem that you originally posted about, and I can't tell if you've come up with a solution, but as far as the rattling/clicking/chattering noise, I don't think it's a fuel OR ignition issue.

Here's my problem - tell me if it's exactly the same as what you are/were experiencing: under heavy load (50%-100% throttle) at around 3000rpm, the chattering begins. The engine loses power and is hesitant to rev. The volume of the noise is more or less related to the throttle position - less throttle equals less noise, more throttle equals more noise. When you come off of boost, the engine revs easily and you can then step on it, around 3500rpm, to get full power.

I think it's the turbo control valve you found in your first post. Yes, it should move, but how freely, and in which directions? It seems like it's too loose by your description. That would explain several mysteries... One - that the chattering only occurs at the transition between the turbos. It is not an exclusively secondary problem... if it were, don't you think you'd hear it throughout the rest of the rev range? Two - that it does not occur under light loads with minimal boost. This since there is not a lot of pressure acting on the system, there won't be a lot of force acting on the valve, and therefore, if it DOES move within the housing, it will not make enough noise to be noticed.

Your injectors are obviously working and you've got spark throughout the rev range. The only thing missing is air. It wants to go, but it can't... the throttle bodies are open, but the secondary turbo isn't getting to blow hard enough to adequately pressurize the manifold.

Eh... just guessing. <--- Often wrong.

 

And you know... how would the HKS Twin Power change your fuel cut? I think it's an unrelated issue. I doubt that fuel tuning with the PFC would do anything to a separate ignition module... all that thing does is provide bigger spark...

 

When the turbos chatter, does it almost sound like a leaf in a fan blade type noise coming from the passenger side floorboard?

 

I have try everything to troubleshoot the problem. I pulled the turbo, check for problem and readjust all turbo control actuator and problem still exist. Finally today I pulled the Twin Power off the car and the car ran fine again.

I have started another post just to talk about Twin Power problem. I will keep the car running for few days without Twin Power. If no problem found, I will put the Twin Power back and see if it will cause the same problem again.

Thanks

BC-FD3S

 

Not to threadjack, but at least in my case, that's pretty close. It almost sounds like it's coming through the tranny sometimes.

Well, BC, good luck... hope you can track down the problem!

 

Bringing this topic up. Besides my other issues with the car, when I start to build boost (3-5 psi) I get this chattering. I know I have a ported WG and that the flapper is a little loose, but doesn't anyone else know what it could be????

Trev

 

guys im having the same problem a noise like something hitting a tin sheet but only under load. i first thought maybe it was a heat shield or something. it only seems to happen when building boost quickly and the knock goes crazy on the pfc right?? theres another thread abou having the harness that connects to the ignition coils rearranged. ive also determined that this is not a mechanical problem but an electrical one. im going to be checking this out within the next day and i will let you all know what i find and if i fixed it.

 

If it's an electrical problem then it's not the turbos.

FYI, the wastegate and turbo control doors have looseness between the door and swing-arm. This is normal.

When the actuator is hooked onto the swing-arm, there should be tension from the actuator that keeps the door pressed closed. It's about 1/16" to 1/8" that you should need to stretch the actuator arm to fit onto the swing arm. So the assembly should not be loose when full assembled and at rest.

Dave

 

Also check the actuator to manifold mounting bolts for looseness. I had a situation in the past where I was getting a similar issue, which sounded like clangy, metallic chatter under boost.