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Discussion Starter · #1 ·
The new turbo is fitted to the 2.3 stg.1.

The old one was well and truly ******! A lot of movement along the shaft - blades with chunks out of them too.

Now much quieter, smoother and lots more
.

Now the bad news........... keep hitting fuel cut off (reading about 1.4bar at this point as near as I can tell- possibly full scale on 1.5 bar guage.)

Pulled fuses and tried an adaption run.....still hits fuel cut off when I've got the brakes dragging.

........Yes the wastegate is connected!!!!!!!!!

Turbo and wastegate of a 75000 mile engine known to be good........

Any ideas?

Alyn
 

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Discussion Starter · #3 ·
Hi Jason,

New plugs a week ago on service,

New DI about 5k miles ago.

Symptoms are a dead cut, followed by an increase in boost, another dead cut....etc. - the DI that was on the way out was a sort of stutter, a missfire - this is like hitting a hard rev limiter.

hmmmmm......

Alyn
 

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You have more experience than I, my car had a stutter until last week and that was fixed by borrowing a DI from another SaabScener. At the time I didn't recognise the symptom as it was the first time I'd come across it. Your definitely hitting overboost judging by those symptoms.

What fuel are you using, out of interest?
 

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Discussion Starter · #5 ·
Always use sainsbury's SUL

But today I even tried optimax - still does it!

Half a mo though - I haven't checked the base boost since H&S fitted the turbo - might that have something to do with it - if its set too high?
(clutching at straws here - I Know)

Alyn
 

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Is the overboost protection an ECU set parameter or a physical switch (like on my '87 9000 T)? If its physical, you can adjust the setting by using a screwdriver, otrherwise, i dont know.
 

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Originally posted by Grentarc:
[qb]Is the overboost protection an ECU set parameter or a physical switch (like on my '87 9000 T)? If its physical, you can adjust the setting by using a screwdriver, otrherwise, i dont know.    [/qb][/b]
Unfortunately not, Al's car is Trionic. It's doubly unfortunate is that all our trionic guru's seem to be otherwise preoccupised at the moment. :/
 

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Originally posted by Al:
[qb]Pulled fuses and tried an adaption run.....still hits fuel cut off when I've got the brakes dragging.

........Yes the wastegate is connected!!!!!!!!!

[/qb][/b]
Ah... a very useful clue...
This means that the wastegate is failing to open. There can be several causes for this. Your APC solenoid might be faulty, or the wastegate actuator. The pipe work might have gone awry between the APC solenoid and the actuator etc. Assuming it was working before, this seems a likely cause.

There are 3 ports on the APC solenoid, going from top to bottom:

C- Compressor
W- Wastegate
R- Return

The pipes are also labelled C, W & R

The C pipe connects to the compressor side of the turbo, W to the actuator, R to the low pressure inlet side of the turbo. It's worth checking these.

The easiest way I've found of testing the wastegate actuator and wastegate is to use compressed air. One of the little 12V power inflation pumps does nicely, especially if it has a preset cutoff pressure. You might also get some effect from a footpump. Pull the W tube off and apply pressure. You should be able to see the actuator arm move.

If you haven't got a pump handy, then pull the C tube off the solenoid and put it directly on to the actuator, having first removed the W tube. Take it out for a drive. If it still overboosts, then we know the problem is with the actuator or a stuck wastegate. If you've gone under the car first while it's cold, and taken the arm off the wastegate and checked the wastegate moves freely, then you know it's a problem with the actuator. I very much doubt it will be base boost set too high on a standard actuator- more likely a leak in the diaphragm.

If the actuator etc works and if you get base boost connected like this when you take it for a test drive, then the problem lies elsewhere. Check all the pipe connections as I suggested.

Check the electrical connection to the solenoid. With the ignition on, you should just be able to hear it buzzing.

HTH
 

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Originally posted by Al:
[qb]I haven't checked the base boost since H&S fitted the turbo - might that have something to do with it - if its set too high?
(clutching at straws here - I Know)

Alyn [/qb][/b]
Alyn, I think you have the answer - it is not clutching at straws at all.

Coincidentally, I was experiencing a similar problem as you today. With turbo under full load in third gear the car hit the fuel cut-off.


This was soon cured by checking the base-boost value and adjusting the wastegate actuator rod to reduce the base boost accordingly.


Sounds like your base boost is set too high.
 

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Discussion Starter · #10 ·
Mark E

- Checked all pipes - good connections - right order.

Nice tip about the 12v compressor - actuator arm moves well - saves me going red in the face!


Solenoid hums nicely to itself.

Thanks for the input.

John/

hmmmmmm - overboost in 3rd once, 4th and top - everytime

solenoid hums,hoses good, actuator moves, software works (did before! and I've not changed it!)DI - good, new plugs.

I think I'll ring H&S in the morning and book it in for a little bit of backing off on the old base boost!

Thanks for the confirmation - not clutching at straws - merely barking mad!

Alyn
 

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Originally posted by Al:
[qb]John/

hmmmmmm - overboost in 3rd once, 4th and top - everytime
[/qb][/b]
Yep - base boost sounds like the problem then. I could fully load the turbo in second gear and the car was taking off like a missile, no problem, fully load the turbo in third and it still went like a missile but there was a hiccup as
it overboosted.

Did not get to try 4th or 5th as we had a fairly short, erm, runway to test it on


Can you get H&S to check the base boost at the moment before you adjust it? Mine must have been wound up to around 0.8bar when the standard on the 9-3 is 0.45 IIRC. Acceleration was awesome whilst at incorrect base setting
 

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Discussion Starter · #12 ·
Close inspection in the cold light of day revealed that the MAP sensor hose was somewhat perished at the ends and a very sloppy fit.

I replaced it with a length of Elkparts blue silicone hose (It was all that I could find.

Dead cut only happens in top gear about 50% of the time now - all other gears seem OK - but the roads are so wet maybe I bottled out.

Read somewhere that the MAP hose is critical in both length and material - can anyone confirm?

If it is maybe I should get that replaced first and see how it goes from there?

Cheers

Alyn
 

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the current thinking is that the map sensor hose is critical in length and material (I do not know why but lots have people have said this ....)
however smomething non optimal is probably better than what you had
 

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Discussion Starter · #14 ·
Hmmmmmmmmm.............a little learning etc.

If I was the experimental type, I guess that I could try different lengths of different materials to try to tune out the cut off.......

BUT - oh yes! there always has to be a but, -

I would have no idea what the MAP sensor would be telling the ECU, and what the ECU would do in terms of fueling and advance etc.


New MAP sensor hose I think, then check base boost.

Alyn
 

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Discussion Starter · #15 ·
Ooops forgot to ask...

As a matter of interest does anyone know if the same hose is fitted to all models, i.e LPT,T, Aero,2.0 and 2.3.

Same part number etc.?

Alyn
 

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It's the same hose, but it does vary in length. Persoanlly I'm scpetical abut the theory that it must be exactly the right material and length... I ran mine for a while with silicon tubing and did't have any problems.

Hpwever, you can buy it from main dealers, they keep it bulk on a drum. If you ask them nicely, they might even let you have it for free!

If you're hitting overboost with brakes on, then it's either the base boost set waaayyy too high (which as I said is doubtful) or a fault in the APC system. What sort of pressure did you have ot apply with the compressor to move the arm? Try the direct connection of the C tube to the actuator as I suggested and that will determine where the problem lies.
 

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Discussion Starter · #17 ·
Car booked in for this weekend at Hallam and Southerns, been driving with very light right foot.

Today max boost = 1bar then tapers to less than that.

Lost about .5 bar somewhere....

I think that the wastegate might be sticky - same fuel, nothing changed ........no where near as much fun though.

Anyone got any ideas?

(Did an adaption run just in case........... still the same)

Alyn
 
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