Wastegate Issues

[CDeutsch]

If possible, recirculate your BOV and see if it goes away. I'd start there to rule it out.

Could be spark blowout if it's happening at WOT, I've only had problems with BOVs at part throttle (so far).

[sleepydsm]

Ok, well I tightened the BOV. That problem is solved. BUT with a boost controller on, the boost flies up to whatever it wants. It acts as if the wastegate is not hooked up.
This is hard to explain, sorry. The car only jerks and studders when you're at partial throttle, and the boost is building up. It gets to a certain point and just bucks and jerks around. At WOT, the car is fine, its just the boost is uncontrolled so that is a problem. Without a boost controller, my wastegate works fine. When the MBC is hooked up, the wastegate acts like it isnt seeing boost/vaccum. (so basically the boost is uncontrolled, and goes to whatever). I originally had an Elite MBC, so I tried another one. And the same problem is happening. And yes the screw is back out as far as possible. Any ideas? I'm gonna do a boost leak test, and see if possibly the MBC is leaking somehow, and therefore the wastgate acts as if it is NOT hooked up.

On another note, I wasn't having an issue with knock at all. I was hoping to run about 18-20 psi on 92 pump gas.

Thank you all for your input!
Kevin Swalchick.

[Shane@DBPerformance]

Are you hooking the boost controllers up backwards?

[sleepydsm]

They were not hooked up backwards. I put an Elite MBC back on, and it actually controls the boost. The other shitty one I had... the spring was WAY too stiff.

Ok, now on another note. The BOV is set a lot stiffer, I have a MBC that controls boost, and its set at about 20psi in 3rd. In 2nd gear at about 5-6K RPM I get a loud pop the car jerks. Again, it feels like the wastegate is opening. Could it be the BOV again? (too stiff, not stiff enough). Some sort of ignition problem? Or just some kind of tuning issue (way too rich)?

Again, thanks for all the help. Thats why this board is awesome.

[JET]

Alright, set the boost to 15 lbs and tune the car there. That will get you a rough tune, then bump it up from there. Don't try and go straight to 20 lbs, it is way too difficult to tune it close to the ragged edge, especially with nowhere to start and a novice tuner. I don't even think you should run around at 20 psi until you have it totally dialed in at 17 or so.

[Shane@DBPerformance]

In 2nd gear at about 5-6K RPM I get a loud pop the car jerks.

Fuel cut? If it's a hard jerk, it might be fuel cut. If it's just a sputtering then it could be an ignition problem or just way too rich.

[dsm10sec]

Look on your MAFT and find out if the dipswitch on it is set to fuel cut on or off.

[sleepydsm]

OK. Thank you all for the advice. I will do what JET suggested, I'm gonna turn down the boost and work from there. I'm pretty sure its a tuning issue. At about 4500 rpm, I would get 20 counts of knock, no matter how much more fuel I'd add. As soon as it hits about 4500rpm, in any gear above 1st, as long as I'm making boost, it jerks and knocks.

BUT... I did get a check engine light, it said Code 44. Ignition coil... This problem has been around for a bit, I replaced the ignition transistor pack thing (not the coil) and it seemed to go away. Could a faulty coil be one of the causes for this problem?

Could an ECU on the way to Shitsville cause any of this either... I've never replaced the caps...

[slowbubblecar]

The coil can cause a misfire because a cylinder or 2 might not be getting spark. I think the wastegate has a 20 pound spring in it. I had the car run good at 20psi and pump gas before with that turbo. The 60 trim worked well at 25 pump with no knock.

[sleepydsm]

The spring in the wastegate is yellow. Looking in my handy HKS catolog, the yellow spring for a standard wastegate is 14.7psi, or 1 BAR, as it says on the wastegate written with a Sharpie ;) Well then I'm gonna get an OEM coil, and see whats going on then.

No matter what I get a misfire/popping/jerking motion at 4500rpm. About 20 counts of knock no matter how much fuel I add.

I'll get a coil soon. Until then I'll try and take 'er easy. Driving like a grandma sucks.