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Discussion Starter · #1 ·
When accelerating the car, eveything is fine until the boost hits the end of the white. At that point, the car basically loses any additional boost. It's as if the engine is the only thing making the car go faster at that point. Slight hesitation occurs at that point if you really punch the gas, but no bucking or anything crazy, it's pretty slight. The car will go faster, but just at a slower rate of aceleration, and a little less smooth than if the turbo was fully functioning. The boost gauge won't go past the end of the white.

From my searches it seems like this could be from 3 things.
Bad boost pressure control valve, bypass control valve, or a stuck waste gate.

The boost pressure control valve has 2 prongs for the plug,
but I don't know the specs to test it in terms of resistance, if that's even possible.

The bypass control valve I know you can apply vacuum to one side,
closest to the battery, and it should have resistance/no flow.

The waste gate I have no idea how to diagnose or test.
It seems like you have to rip it apart and see if it's intact mechanically or something.

Any input would help, thanks. Vacuum lines seem fine. The car is actually more responsive (up until the yellow boost mark) than my 9-3SE HOT which has 90k miles! This one is a 9-3 convertable, dunno if it's HOT or not, but it has 115k miles and is within +/- a year or two of mine, which makes me sad.....but yeah, that's another story.
 

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The white area indicates vacuum, not boost, so you really aren't making any boost.

The first thing that I would check is the rod that actuates the waste gate. It may have fallen off. While you're looking at the waste gate, move the rod (it's kind of hard to move) to see if the waste gate is stuck.

Do you hear anything like air rushing out? If you do, you may have popped an intercooler hose, or punctured the intercooler.

Finally, make sure that the delivery pipe is attached to the top of the throttle body... Ron
 

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If you popped a hole in the intercooler or popped a pipe loose you probably won't be able to keep the car running because of the MASS.

My guess is the Turbo is blown.

Pull the intercooler pipe off and check for oil in the pipe..
Pull the cobra pipe off and see if the compressor wheel is loose.
I'd also check the actuator and rod.

Make sure u do all of this with the motor cold.
 

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The white area indicates vacuum, not boost, so you really aren't making any boost.

The first thing that I would check is the rod that actuates the waste gate. It may have fallen off. While you're looking at the waste gate, move the rod (it's kind of hard to move) to see if the waste gate is stuck.

Do you hear anything like air rushing out? If you do, you may have popped an intercooler hose, or punctured the intercooler.

Finally, make sure that the delivery pipe is attached to the top of the throttle body... Ron

Was it a sudden loss of power and boost? I'm with Ron and would check the wastegate actuator rod first. This popped off on my car a few years ago and behaved as you're describing.
 

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Discussion Starter · #5 ·
When I punch the gas it seems like the turbo kicks in just fine.
Even more power than my 9-3 with 25k less miles on it - which now has new spark plugs and new vacuum lines..and is a HOT..
There is a typical delayed acceleration and then power from after the turbo spools up after a second or so.

But then, after another second, by the time the gauge hits the beginning of the yellow, it stops and stays there.
Acceleration of the car seems like it would if the gauge was at the end of the white, but the...acceleration of the acceleration stops.
From there on in it's the engine making the car accelerate. Slight hesitation after that but only very slight.

So, I should be able to push (into the wastegate assembly)/pull (away from the wastegate assembly) the wastegate rod with my hand?
I'll try it on my working 9-3 and then compare on this one.

I don't hear any air or any odd noises, the car sounds fine. I'm pretty sure everything is all connected up. No oil burning either.
I looked at vacuum lines and they are all fine.
 

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I'd pull an intercooler pipe off and look inside for oil.
Sounds to me like a bad Turbo. Could be a bad boost valve or bypass valve too.
 

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calm down with the blown turbo, guy


start with the simple things
check for boost leaks
check your bypass valve (is it the original? you probly need a new one now)
check the wastegate arm
 

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2002 will be T7 and the boost gauge in the dash is not a 'boost' gauge it's an engine power guage. Inability to make power may be turbo limited or it may be some other fault causing the ECU to restrict power.
 

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calm down with the blown turbo, guy


start with the simple things
check for boost leaks
check your bypass valve (is it the original? you probly need a new one now)
check the wastegate arm

Hey, I gave all those options too. But its not like a blown Turbo isn't possible.
 

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Discussion Starter · #10 ·
Thanks all, I was going to check the boost pressure control valve, I thought I read somewhere that there were three plug prongs and you could check resistance across them and they should read 3ohm. Then I pulled it off and there were only two prongs.

I'll give the bypass control valve a check by sucking on the vacuum line, although last time that failed on my other 9-3 it threw a code for that.

Not sure how to check the boost pressure control valve, I read things about removing this or that vacuum line on it and driving to see what happens to see if fuel cutoff is engaged, to verify if the turbo/vacuum system is working, but this isn't my car and I really don't want to slam the engine until it abruptly cuts fuel off, that sounds like a terrible idea to subject an engine to and I want to avoid that, so I'm not doing that. Plus, if the bypass control valve wasn't working you'd think it'd throw a code. There are no codes.

If I had to guess it seems like the wastegate is at fault but who knows. Will check what you guys said and get back to you all, thanks so much for the info, always greatly appreciated.
 

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calm down with the blown turbo, guy


start with the simple things
check for boost leaks
check your bypass valve (is it the original? you probly need a new one now)
check the wastegate arm
Agreed. Dont assume the absolute worst right away. Look for simple things first...leaks, etc.
 

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WOW, same thing happened to me about two weeks ago on the highway. Traveling to work one morning I downshifted and put my foot on the gas and the "wall" as described earlier by the OP was felt. No CEL, no funny smells, no increased air sounds or anything. Car is a 99 S-model with 146K on the clock. Checked WG and it springs back find. visually checked VAC lines coming from Boost device to the left of the radiator and fan.

I did read from some owners overseas that there is a chance that the fiber filled mufflers breaks down after many years and basically clogs the exhaust which limits power. I found a small plumbers snake to put into the exhaust pipe to see if anything could be felt and pulled out but nothing. Also, I was told that if I disconnect the dump pipe where it connects to the rest of the exhaust and run the car that if power returns then a clogged muffler would be the culprit. Any takers?
 

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Discussion Starter · #14 ·
I ended up not having the time to check the relatively simple things suggested in this thread, but the car was brought to a pretty reliable saab certified independent mechanic and we are being told that the DI is bad and is retarding the timing and therefore messing with the turbo and that's why the car is hitting 'the wall'
 

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I left work on Wednesday and unplugged the vac line from the bpc to the Wastegate and nothing changed. Going to check my charge piping leading to the throttle body to see if oil is visible. Also, after we get situated with the move, then I will unbolt the exhaust at the DP to see if boost comes back, meaning a clogged exahust somewhere.
 

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Did your engine light on the dash go on too? Had my Viggen on the highway today got a flashing engine light, no check engine on the SID, then about 15m later the engine light came back on as a constant. Rest of the ride out the turbo wouldn't spool past center (middle orange). Engine runs and sounds fine so hoping it's just the DIC (especially since I've only had the car for 300miles). But that light freaked me out a bit.
 

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Discussion Starter · #18 ·
Well, got the $314 DI cassette from Eeuroparts. They claim it's "high quality." Hopefully it'll fix this issue. We'll see next week.
 

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BBaller. No flashing CEL or anything. As a matter of fact in late December early January the car did what you explained. However I disconnected the Negative terminal for about 2hrs or so and car was back to normal. I tried the same thing this time thinking it was a similar problem, however nothing. So I have ruled out the BPV, have not checked the charge pipe going to the throttle body for oil or disconnected the dump pipe from the rest of the exhaust. I need to figure out something. Car feels like my 95 Civic DX 1.5. All of 95hp I beleive and 60lb of torque.
 
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