Possible wastegate actuator problem

Juffa · Postby **Juffa** » Mon Jul 03, 2006 9:57 pm

I have been trying to set a target boost level for my newly installed (2nd hand)turbo. I have tried to set it to 6 pounds, just until I can make sure I have any real bugs irnoed out, before I increase the boost. What I have found is that I am getting around 9 pounds and would probably go higher if I didn't back off the go pedal. I have a FM supplied electronic boost controller fitted to allow the FM ECU to control the boost.

I suspect that I have a faulty actuator on the turbo wastegate. I did a simple check tonight (as found on the big forum). I disconnected the actuator rod from the wastgate and tried to push the rod back into the actuator housing. The idea is that when you push the rod in, you place a finger over the vac nipple on the actuator, then release the pressure on the rod and remove your finger from the nipple. If the diaphragm in the actuator is ok you should hear a small sucking sound.

I found that I could not push the rod in. I could only pull it out, against the spring. I suspect that the wastegate is fully closed and therefore is not offering any boost control function?

Any help would be appreciated.

If I need to repalce the actuator, wher would be a good source?
J

ampz · Postby **ampz** » Tue Jul 04, 2006 1:46 pm

Hey Juffa,

Just a thought. What if you pull out the actuator arm and release it, does the vacuum hose suck then? It may be fitted in reverse.

ps: i don't really know as i have not seen your setup, but you may have an actuator that operates in the reverse of what is being used in your application. In which case if you have room just put the wastegate lever 180 degrees out to make it push to close instead of pull to close.

That's the best i can do with the lack of sleep due to the world cup!!!

Juffa · Postby **Juffa** » Tue Jul 04, 2006 2:49 pm

ampz wrote:Hey Juffa,

Just a thought. What if you pull out the actuator arm and release it, does the vacuum hose suck then? It may be fitted in reverse.

Thanks ampz
The vac hose doesn't suck if I pull out the actuator arm. I believe that the pressure from the turbo is supposed to push the actuator arm out, thus opening the wastegate until the boost target is reached. It is plumped into the turbo and wastegate similar to when the previous owner had it, except I have replaced the manual screw type boost controller with an electronic one.

J

Garry · Postby **Garry** » Tue Jul 04, 2006 3:57 pm

I can only pull mine

ampz · Postby **ampz** » Tue Jul 04, 2006 4:06 pm

So is this electronic boost controller somehow connected to this acuator arm?
(excuse my stoopidity, but i haven't played with electronic boost control before)
If so, wouldn't it need to have a sense of where/what pressure the turbo is at before it opens the wastegate? (like a solenoid perhaps)
or does it sit between the can and the wastegate lever... with a solenoid in between?

The Pupat · Postby **The Pupat** » Tue Jul 04, 2006 6:28 pm

ampz wrote:So is this electronic boost controller somehow connected to this acuator arm?
(excuse my stoopidity, but i haven't played with electronic boost control before)
If so, wouldn't it need to have a sense of where/what pressure the turbo is at before it opens the wastegate? (like a solenoid perhaps)
or does it sit between the can and the wastegate lever... with a solenoid in between?

I believe most just replace the manual valve put between in the pipe that runs to the wastegate EI interupts the "pressure signal" to the wastegate.

Juffa · Postby **Juffa** » Tue Jul 04, 2006 10:01 pm

Well, I pulled the actuator and arm of the turbo tonight (as you do). I attached a bicycle pump to it and applied some pressure. The arm did extend and held position while the pressure held. So now I'm thinking that the actuator is actually ok. I suspect I did not have the vac hose, that should supply the pressure, attached to the right spot. I'm now going to attach it to the vac nipple on the throttle body, shared with the BOV.

When plumbed correctly into the hose that feeds the wastegate actuator, the boost controller \"bleeds off\" a measured amount of air to reduce the pressure in the hose. This sends a lower boost signal to the actuator, so that the wastegate will remain closed for longer, thus increasing the boost level. The end result is that the turbo is producing more boost, but the wastegate doesn't know. The FM ECU can read the signal pressure and adjust the \"bleed\" to keep the boost at the set target level. (or so the manual says).

J