I jumped in the old jelopy the other day and went for a short drive. Turning left out of a side street on to a busy road I gave it some and my god did I get a surprise. Took off a lot harder than I expected. Then BANG!

It was just an IC coupler blowing off so no big deal.

I drove home with no boost and put it back together tightly. Took it for a test drive and noticed that my boost was not being limited by the wastegate. It was going as high as 1.5bar (23psi) with audible detonation and awesome power.

Decided to have a think about it. Either the wastegate solenoid is playing up (unlikely), a vacuum or pressure line is crimped (possible) or the wastegate is jammed.

Took it for a quick run this morning and it was over boosting but after a while started behaving again. But i still need to get to the bottom of this.

Some background: LoveFab V1, GT3071R, Tial 44mm wastegate, GM boost solenoid and AEM EMS. Wastegate has a 6psi spring but AEM/solenoid is set to 8.5psi.

I had a cracked manifold recently so have had the thing in pieces but it was working fine when i put it back together.

Questions:
Are Tial wastegates prone to jamming?
Does a fault in the solenoid usually result in no boost limitation or revert to being controlled by the spring?
I assume a crimped boost line from the turbo would result in no wastegate control?

 

try bypassing the boost solenoid conect a vacume line directly from the wg to the turbo compressor housing if u only boost 6 psi its not the wg

 

I was going to do that, but now the problem has gone it really won't show anything.

 

t bolt clamps

 

Thanks JDM. Maybe try reading the question first.

 

 

Check the power source to the solenoid. I had mine connected like the water pump on a comptech kit (to the heater hose relay). When my Rad fans kicked on my solenoid would freak out and didn't do what it was supposed to. I had to move to another power sourse to get it working right. And it was like that for almost 8000 miles, for some reason it just started doing it one day. It has worked fine since the change.

 

I had this problem and it turned out to be a vacuum line that looked fine, but on closer inspection it was slightly cracked on the end that connects to the waste gate. Apparently months of heat cycles weakened it and caused it to crack.

 

AusS2000 I had the same problem a while back once I had to weld the mani as well.
Try to check all vacuum lines.Take the vacuum line off the boost controller and blow into it. It should be tight. Mine's wasn't and I found out that the fitting on the side of the WG got loose. Had the same thing going on as you, it worked once it got hot, just to overboost 10min later.Do not overtighten in in case it got loose, it's really soft and easy to ruin the thread. Don't ask me how I know

Regarding your manifold, I feel kind of sorry for you but on the other hand it feels good to know that I am not the only one who cracked it. Hold up fine since I welded 2 brackets on top of it in a V shape to support the weight of the turbo. Try that.

 

LOL Jakub, I suspect there are a lot of people out there that are glad my manifold finally cracked. I've been impressed by everyone's restraint.

I have a feeling it's line related as they all had to come off for the repair and some were pretty tight and needed to be forced. Mind you, mine are all high quality red silicone hoses.

I'll drive again before the weekend and see if the problem reoccurs. If it does I'll try the solenoid bypass as per GDm's post and can check the vac lines at the same time.

ANd if it turns out to be a the solenoid I'll check it's operation too.