86 951 Driver

After discussing with my wife about a certain 944 S2 on rennlist I guess old girl(951) is angry. The car ran great yesterday no issues. Full boost when appropriate, and overall ran fine. I did use the A/C yesterday, but that is the only difference in my routine.

This morning I start the car up and idle and vacuum both look fine. I drive a few miles before merging onto the highway, I go WOT nothing happens. The car just slowly creeps along. No boost what so ever. So I let out and just get it enough throttle to get up to speed. I tried to go WOT a few more times in 4th, 5th gear nothing. No boost at all. As I am getting off the highway I thought I would try a lower gear for boost. No boost in any of the gears.

When I got to work I checked the vacuum lines that I can see(mind you my vacuum is around 17-18 on the boost gauge). Nothing appears to be unhooked or changed since yesterday.

Car is stock minus a gutted cat and K&N cone filter. Turbo(K26/6) was rebuilt 3 years ago by Lindsey Racing.

Could this be an AFM or wastegate issue?

Paulyy

Id check the compressor wheel.

86 951 Driver

I really hope that isn't the issue. If it is I will most likely shiz myself.

divil

Did you check your TPS connector? I tried unplugging mine a while back to track down another problem, and it almost completely eliminated boost. In almost every other way the car was the same.

86 951 Driver

Would you get any boost at all? My car is making 0 boost. Should I try to hook up that test light to the test port?

User 52121

0 on an aftermarket gauge?

divil

I couldn't swear that it was zero, I only have the stock gauge to it was hard to say for sure.

User 52121

A stock WG with no boost control will only run about 4psi, which will certainly FEEL like "0 boost" and I imagine 0psi will barely register on the dash gauge.

Kinda depends on if it really is making, truly, 0psi. An aftermarket gauge will tell that for sure.

If it's truly making 0psi, then I'd pull the J-boot and have a look at the compressor wheel. Otherwise I'd have a look at your boost controller.

86 951 Driver

I have an external gauge and both that and my stock gauge were reading about 0. Might have been 1 or 2 PSI tops.

My boost control is all stock. Nothing has changed. How much damage will be done if my turbo is seized up?

odb812

How does the car behave on the way to 0 psi? Does it come out of the vacuum as it normally would, just not make any boost pressure? Or is it slower to approach 0 psi?

86 951 Driver

To me it acts normal until you get to the point where you would normally have that turbo spooling up. It doesn't seem any slower approaching 0 psi.

Tom M'Guinn

Could be the wastegate too--stuck open, bad diaphragm, burnt out wg valve, etc. Or even a nasty exhaust leak...

86 951 Driver

The car drove perfectly fine yesterday. Spooled up good and everything.

User 52121

I'd check the compressor wheel (easy enough, just pull the j-boot and have a look). If that's fine, then look at the WG. Could be stuck open. Easy way to tell... the short pipe that ties the WG into the exhaust will be hot as the car idles because the exhaust will be flowing through it. (Normally at idle the WG is closed...)

User 41221

If it was fine yesterday and you have nothing today, I wouldn't immediately jump to the conclusion that its your turbo. You are still running the factory cycling valve, correct? I'd start there. After that, I'd clamp the wastegate line and see if you get boost. IF that doesn't do it, then you can start thinking about the turbo.