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Another boost issue...I'm out of ideas.

3K views 28 replies 7 participants last post by  davide c 
#1 · (Edited)
Hey guys!

I know, there are plenty of other threads out there, with a lot of things to try. However, I have tried the most things I've read on forums and tips I get from the Saab community (Absolutely love it, by the way :cheesy: ), without solving my problem.
Long text, but please bare with me! ;ol;

My car is a 9000 CSE -95, low pressure turbo. I got help from Richard Labarre with a new ECU with more power. Great guy, really helpful!
So I installed the ECU, together with the T7 MAC valve and cable adapter that Labarre hooked me up with. If I understood it correctly, he converted the ECU to T7 so that I can run a T7 BPC valve, which is much cheaper than the T5 ones. The car is running great, but lacks boost. No change. Pity! I let it be for a while, but I am now trying to fix the problem. It's supposed to boost like 15-16 psi, but I only get base boost (6-7 psi). The base boost was even lower at first, but I could with some instructions shorten the wastegate arm so that when running base boost only, I get 6-7 psi.

The car has problems holding even this low boost too, so I guess there is a leak but I haven't found it yet. :roll:

This is what I have done/checked:

Wastegate and Turbo:
  • I removed the vacuum hose from the BPC valve (the MAC one) on the wastegate and GENTLY applied throttle. Nothing happend, were too much of a chicken. However, when driving home and not remembering the "mod", I gave it a bit more. Geez! :eek: Lost all traction for a half of a second before letting go by reflex. Haven't tried it since, but that should mean the turbo isn't the problem, right?

Bypass Valve (/Blowoff Valve?):
  • Can't see any cracks or rips in the membrane. Can't hear any high pitch sounds of leaking air from it when idling/revving the engine without load.
  • Unplugged it from the turbo inlet and checked the functionality. Seems fine...I think...please take a look.
  • Unplugged both connections (but not the vacuum hose from the manifold), plugged the hoses and gently tried it. The boost did not increase, but rather decreased. Guess that rules out a BPV leak, right?
  • I did try to test the BPV off the car before though, and it leaked at 6-7 psi. So I though that was the problem, but then I read that the spring inside it needs pressure from the intake manifold (the vacuum hose) to keep closed which made me believe my test was no good.

Vacuum/Pressure Hoses and their connections:
  • I have listened, felt and looked for cracks and leaks. I have used soapy water, no signs of leaks.
  • Hose clamps and zip ties have been added where vacuum hoses didn't have any.

Manifolds and throttle body:
  • I've used start gas around the intake manifold, throttle body and at the fuel injectors. The engine did not run different (apparently a sign of a vacuum leak).
  • I've used soapy water around both manifolds, the throttle body and everywhere on the motor where I suspected a leak.

Intercooler:
  • I have looked for cracks and listened for leaks. I do however need to do a more thorough inspection of the frames and connection before I am sure they are tight.



I'm all out of ideas. Maybe it's a ECU problem, but I've checked fuse #17 (someone told me that was the one for the APC, but I'm not sure because it doesn't say APC at any fuse in the glove compartment). And I rather keep believing Labarre did his job well. Many people have praised his free service (yes he did program ECU's free of charge at that time, before people started using him and not returning the old ECU's), so I hardly think there is a problem in the programming. The car runs great otherwise.

If you know any more tests, or have an idea of what could be wrong, please share it with me! =)


Thanks for taking interest!
//Adam
 
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#2 ·
Cigar test?

Is the cigar smoking test reliable? Even for small leaks? But I should have a big *ss leak if I'm loosing 10 psi...

Would the ECU let you get full boost if it indicates a leak in the intercooler?

Oh, and I do not receive any fault codes when using a OBD2 bluetooth dongle and the Torque application on my phone.
 
#3 ·
Long shot but have you looked at the glued in nipple that connects the AIC valve around the throttle body? Mine fell out but only leaked intermittently at first giving very strange engine performance. Its hard to glue back in so my mechanic cable tied it back together and now all us well again. It's quite hard to see this connection under the intake bellows.
 
#7 ·
Hmm I'm not sure I understand which nipple you mean. A nipple for a vacuum hose or pressure hose?
AIC valve? Air intake controller valve? :confused:
 
#4 ·
Ooops!

Heh, oh well. Here it goes.

When checking the fuses way back, I must have done a horrible job. There wasn't even a fuse in the APC-slot (didn't find it when I checked).

So now I got her boosting at least.
But she's jumping all over the place when boosting more than 0.5 bar. Also, the boost gauge meter leaks a lot of air over 0.6 bar, but that shouldn't be too hard to fix.

Could it be that I just have to let her adjust for a while before she settles down with the extra power, or is something else wrong? When boosting over 0.6 bar, it feels like she is loosing power instead of getting more.
She feels a lot slower when trying to accelerate fast on first gear, she just looses all power after a second. I did get more power before I got the APC to work.

Any ideas?
 
#6 ·
As for the loss of power under boost, did you add an intercooler to match the ECU upgrade? The ECU may be retarding ignition to protect the engine.
Do I really need an upgraded cooling system for 15-16 psi of boost?

I do think I have an extra intercooler already though. But I'm not sure of it. 3 coolers, one which cools down the intake air, and a small one for cooling the turbo oil. I think that's their purposes anyway. Can check next time I go out to the car.

How does the ECU see that? By monitoring the intake air temperature?
 
#8 ·
My mistake, you did mention you had an intercooler.

The IAC fitting is at the bottom of the throttle body, right before the plate.

You can see it if you pull the elbow off the throttle body.

How are the spark plugs? Weak DI cassettes can have trouble firing under high boost pressure.

Does the car build boost around 2K RPM?
 
#9 ·
Well, I haven't done a service yet this year. I wanted to get her boosting before doing a more thorough service; new gaskets, thermostat, motor and gear box oil change, stuff like that. But maybe I should buy a new set of spark plugs to see if that works.

Which ones are good for it? 9000 CSE -95, boosting 15-16 psi.
NGK recommends the BCPR7ES-11 or BCPR7EIX-11 (Iridium IX, which they claim is "for the performance enthusiast") for the aero, which is approx. 10hp more than my car should have.

Or should I just go for the standard ones? (BCPR7ES-11)

I don't know that much about the difference of the spark plugs. I've always bought the ones they tell me to. For me the gap is the important stuff, are there any real difference between the high power ones (e.g. NGKs Iridium IX) and the standard ones?
 
#10 ·
Before doing power modifications you need to do basics like plugs and ensure the DI is strong. Since the plugs are part of the knock sensor/timing control system I would only use the ES style plugs. The DI wasn't designed with/for the Iridium plug.
 
#12 ·
The specified NGK plugs are ~2mm longer than others, which has direct effect on the DI's goofy spring connector/ contact lashup.
A shorter plug, not adequately seating against that spring does Bad things to the DI.
IMO quite a mickey mouse design detail in such a sophisticated Electro Gizmo.
 
#13 ·
But which spark plugs do you guys recommend? The ones recommended for the aero, or the ones for a standard turbo (isn't it a difference between the LPT and FPT?).

15-16 psi turbo boost.
 
#14 ·
I think there's no difference for 95 model year.

Anyway, I use the iridiums in my stock tuned 97 Aero and they work really well.

I had good results using platinum tipped NGK but switched when it was pointed out to me that NGK recommend iridium but not platinum for the 9000 turbos.
 
#17 ·
I think there's no difference for 95 model year.
Yeah, well my car was stock LPT, but now it's supposed to boost 15-16 psi instead. My question is if I need to get spark plugs for higher performance for the extra ~40 hp my car theoretically have. I'm sure I'll try the iridium if they are not too expensive, but I'm wondering wether to go standard plugs or the ones recommended for a stock aero.
 
#16 ·
A couple of videos of the car boosting

Yeah okey so I've tried to record the car boosting. The recordings are not great and I don't really know if you can get anything from them. The lack of power is something you feel mostly, but maybe you see it on the speedometer. I believe there is still a leak in my boost gauge meter, because the needle behaves strangely when I'm trying to boost as hard as I can (the car is supposed to boost ~1.15 bar, not the 1.5 bar the needle reaches sometimes.).

Haven't installed new spark plugs yet. Need to wait a month to get some money for that, I'm all out of it right now.

Vid 1: http://youtu.be/b-lGblup_Zg
Vid 2: http://youtu.be/7IzI-LlZtwg
Vid 3: http://youtu.be/8wHnFIdGAE0
 
#20 ·
Ok, so you're saying I shouldn't expect 16 psi then? I thought the FPT boosted around 15-16 psi.

But what bugs me is that somehow all my power is lost when accelerating. Got any ideas? Could it be that simple that it's the old spark plugs that need to be replaced? Seems to easy...usually it's not that easy :)
 
#25 ·
Fuel cut is when the injectors stop firing for about a second due to excessive boost.

It's a complete and sudden loss of power, not a fuel pressure issue.
That actually sounds like my power loss, but sometimes the loss of power is longer. Like for 5 seconds. This happens when I push the throttle down all the way and don't let the boost build up slowly. Maybe that happens to all turbo driven cars? Can you floor it and still get a good acceleration?
 
#26 ·
Well after some driving, I've noticed that I don't loose power on second gear, and when continuing accelerating "hard" on third gear I won't loose power. I boost around 1.15 bar (the boost drops somewhat but not fast enough to bother me right now. I guess there still is a leak somewhere).

If I start accelerating from around 60km/h on third gear instead, the car tugs along with a quite unstable power distribution (seconds of accelerating alternating with seconds of total lack of power) as soon as I boost over 0.5 bar.

When finally reaching a higher speed/revs, the power returns.

What might do this behavior when boosting on low revs?
 
#27 ·
Fuel cutoff at overboost is Unmistakeable One's face tries to plant itself on the windshield. No ambiguity whatsoever.
As a Guess :) perhaps your Wastegate actuator has lost some of it's hold the wastegate disc fully closed.. strength.
An age issue..that happens to most all Actuators... eventually.
ECU limits boost in 1st And 2nd gear, in a 5 spd and 1st range in an Autobox.. by design.
 
#29 ·
Do the check above ..until you run into the "real" Fuel cutoff :)
Once.. is enough to verify healthy actuator spring function.
IF.. it passes that test then there is probability that you have one of the wrong sized C hole Boost control solenoids A few T7 valves were fitted with an oversized (certainly so for a T5.5 car retrofit )~1.4 mm.
Not nearly as simple as simply dumping a different code into the memory chips and calling it stge x :)
Suggest diying a small plug with a 1mm drill hole and inserting it into the first 1/2 inch of the C hose where it attaches to the T7 valve (top one but it's marked)
Test this with care It will either work perfectly or you will run into real :) fuel cutoff ..frequently..in which case that hole is a bit undersized. Resize it to correct.
Good luck
 
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