[johncc]

Me again! Went to look at another 9000 CSE 2.3 FPT, P Reg, 85,000 miles. Nice tidy car, but one problem... it was sloooow!

It has a full dealer history, loads of receipts, last service at 79,000. The guy says it drives now as it always has.

To me it seemed really sluggish and lacklustre. It doesn't seem to misfire or run badly, and it boosts up to the broken yellow/red section.

What could this be? I've heard people say that no two turbo'd cars are alike, depends how they've been driven, etc. I'm just worried it may indicate a problem, but that's hard to believe on such a well maintained car.

Also, I've only got mine to compare to, and who knows, that may be tweaked! It does boost mid-way into the red, but I'm used to that surge forward when you floor it, and this one just didn't have it.

Any kind person want to come and drive mine and tell me if it's standard?

 

[slidejules]

Hi John,

What were you comparing it to? Several different factors can affect the performance like you say, even down to the petrol you used. I have found that my car is noticeably quicker if I fill up with petrol from my local Tesco than if I get it from the BP next to where I work, plus I get better mpg. Weird huh?

Also, if you compare earlier against later 2.3 FPTs, the earlier will feel quicker because of different final drive ratio I believe. Not sure of exact crossover details etc. and this may only affect manuals, but I'm sure I remember reading that on this BB somewhere.

Seeya, Jules

 

[johncc]

Thanks slidejules, they are both manuals. Mine is a '91. Guess that could be an important factor!

As for fuel, I know what you mean... I fill up with all kinds of things, and my car seems to have slow days and fast days, also depending on temperature, humidity, phase of moon, etc. Still, the range of variation is nothing like the difference between my car and this other car.

Is there anyone in my approx area (Dorset/Wilts/Hants) with a modern 2.3t manual who'd be up for arranging a comparative drive?

 

[slidejules]

Ha! Found it! From this thread:

Yours, being a 91, probably has this gearbox:

Version 3:
GM75403
'91-'92 2.3 turbo, ABS (ABS/TC in '92)
4.05:1 final drive with bushings behind spider gears

where the P (97?) probably has this one:

Version 6:
FM751xx
'95-'98 CSET and Aero
3.61:1 final drive with bushings behind spider gears

That final drive would make a big difference to what you feel when you

it!

'Fraid I can't help on finding another one to test but I'm sure someone else here will!

Jules

 

[aeropilot]

John,
Also it could be to do with how it's been driven over these 85K miles. If it's been poodled about and not given the

factor too much Trionic will have adapted to this driving style and it may need the ECU fuse pulled, or battery disconnected and then given an adaption run to restore the

....see BillJ's website for the "how to".....
http://www.saab9000.com/procedures/powertr...adaptation.html

 

[johncc]

Thinking about it, could it also be to do with cat/no-cat? Not sure if my '91 has a cat or not... it does have a lambda sensor though. How much difference does a cat make?

 

[johncc]

The vendor is offering to sort the car out. He tried Saab who said the turbo is either working or not working, and if it's not working they replace it! He goes on:

"However I did get the name of a recommended local turbo specialist who would do problem identification (if there is one !) and repair. They will have a look at the car on Wednesday this week with a view to test the boost pressure and see if they can spot any malfunction."

Should I let him go ahead with this, or would it be better to ask for a Saab 40 point check, as someone else suggested to me?

Given how well-maintained the car is, perhaps I should just take the risk and use it as a batering point?

 

[ylee coyote]

It really does not sond as if there is any prob with the car. The main prob being the different final drive ratio...It really does blunts the accln..
I ended up changing the final drive in my aero to the older setting yo give it more

 

[cdcarlsson]

John,

See what the boost pressure is like, it's relativly easy as there is usually a spare nipple on the intake manifold. Just remove the rubber cover and hook up a length of tubing and a boost gauge.
My Aero was decidedly sluggish and had always been like this, it was showing a similar boost on the APC dash gauge to the one you're looking at, but had a shot ECU which meant the APC was not working

The boost was just 10 psi (according to the Snap On datalogger) and a manual bleed valve soon brought back the

at 14.8 psi (1 bar).
Have a look at the fuse for the APC, if it's blown this is the likely problem.

Nick.

 

[adrian]

Also, I've only got mine to compare to, and who knows, that may be tweaked! It does boost mid-way into the red, but I'm used to that surge forward when you floor it, and this one just didn't have it.[/b]

OK so we shouldnt rely on the in dash boost gauge to compare but if your 91 is boosting mid-red and its like my 89 thats about 20 psi

Like the others have said get the boost pressure measured on the new one, should be approx 14 psi. Might be worth getting your current car measured - I bet its tweeked or maybe its Jason special

 

[johncc]

Originally posted by cdcarlsson:
[qb]My Aero was decidedly sluggish and had always been like this, it was showing a similar boost on the APC dash gauge to the one you're looking at, but had a shot ECU which meant the APC was not working  

   

Have a look at the fuse for the APC, if it's blown this is the likely problem.

[/qb][/b]

Would a trionic car run at all without the APC? Does anyone know what they check on a 40 point check, and if they'd pick this up?

 

[cdcarlsson]

Definatly, pull the fuse out and drive, you'll just get base boost at whatever level it's been set to. All the APC does is allow a higher level of boost within programmed limits when the fuel etc. allows it (simplistic, I know).

The ECU doesn't see this as a fault and won't light the 'CHECK ENGINE' on the dash.

Nick.

 

[alan_b]

I agree with all that has been said. When I first drove my Aero I thought it was really slow compared to my old T16. It's the gearing that does it!

Alanb

 

[billj]

The 2.3T's base boost is rather lower than the Aero, so you wouldn't get anywhere near the broken red/yellow if the APC wasn't working unless someone has cranked up the base boost to compensate. I don't think a Trionic car will run if you pull the APC fuse, as that fuse (Fuse 5?) supplies the ECU. That's the fuse I pull when I want to reset the ECU prior to adapting it. Perhaps the '93 Trionic like cdcarlsson's was different (it was different in many other respects).

The factory boost gauges are variable and are really only intended as a general indication of what's going on. An auto will only boost into the broken red/yellow, but a 2.3T manual might touch the red. Your '91 is boosting a bit higher than expected, but Jason's car also does this and previous owners swear that it's unmodified. Does the '91 have TCS? Jason reckons that the TCS cars were allowed to boost a bit higher than non-TCS models because the system could modulate the throttle to prevent wild overboost spikes.

I did find that my Aero felt sluggish at first, compared to my '90 2.3T (which had TCS), but it didn't take long to become accustomed to the higher gearing and being able to power all the way from 30 to 70mph without changing gear is great fun. There is a smoothness with the later 2.3T not so apparent on the older ones, which can be a bit "hectic" (but not so much as the likes of a 2.0 Carlsson).

As has been mentioned, the lower boost might be down to poor fuel, perhaps 95 RON, and was it a warm day when you test-drove it? I wouldn't expect the cat to make much difference, and I'd have thought your '91 probably has one anyway. My '90 did.

When you gun it and let off the gas, does the boost gauge go well to the left on overrun? If not, perhaps the bypass valve is ruptured. This would lead to slight loss of boost. So would a weak wastegate actuator spring. Neither of these is a hugely expensive problem. Another possibility is the intake air temperature sensor which I have had go out of tolerance and cause a lean mixture. In my case, I was still getting full boost with a lack of power, but in more extreme cases I imagine it could cause detonation which would limit boost. Even the spark plugs could be at fault. Saab specify a ridiculously long 30-odd K mile interval for them. My dealer-serviced 2.0LPT manual had 1.4mm (!) gaps when I got it and the DI cassette was on the way out (not apparent on the LPT, but when I tried swapping it to the Aero, it could hardly take any boost without misfiring).

I must say that if it's a decent price, the service history would swing it for me. I'd cross my fingers, hope that it was OK (or that if not, one of the many cheaper fixes turned out to be applicable) and grab it. That's just me, though, and I am quite comfortable with working through the 9000's systems to get it running nicely.

I really can't believe there's anything wrong with the turbo and therefore anything that a turbo specialist could sort out, barring perhaps a faulty bypass valve.

 

[johncc]

Thanks all for the advice.

My '91 doesn't have TCS so who knows why it's so quick! It's a shame it needs so much money spent on it (gearbox, engine mounts, DI, windscreen, wishbone bushes, shocks, discs, headlight glass, leaking sunroof, a bit of rust around the arch) when the book price is only £850 for a good example... it's _still_ a great car in so many ways. But you have to be hardheaded I guess.

Even so, it has to be better to buy a good new car and tweak it up.

I am thinking along the lines of what you say Bill.. I dread to think what a "Turbo Specialist" might do to Saab... I am inclined make the offer in cash again minus the cost of a couple of hours London garage labour for an immediate sale and just take the risk that a good service history means no major problems.

Thanks again everyone..

 

[billj]

Good luck. Keep us up to date.

 

[1989agoodvintage]

Originally posted by JohnCC:
[qb]My '91 doesn't have TCS so who knows why it's so quick! [/qb][/b]

It would be interesting to get hold of more technical data on the old APC units, many of them do underperform (or run too conservatively) whilst others do seem to overperform, suggesting that they've been reprogrammed even if when they haven't. I know Sevenman went from a '92 CD 2.3T to an Aero and was disappointed with the Aero's performance.

Of course the benefit of buying a Trionic car is that there are a wider range of ECU upgrades available if you need more

.

 

[Paco]

Hmm no further mention of the Trionic adapting to the gentle driving technique of the previous owner?

Has this been ruled out?

Go for it John!

Hasn't anyone bought that Aero yet????

 

[johncc]

For better or worse, I've decided to let them go ahead and pay these people Boxer Motor Works have a look at it. Sounds like they will spend an hour giving it a once over, test the boost etc. and make a report, without modding anything. They reckon they will spot anything obvious and "after that it's a grey area" as the mechanic said. Still, probably worth doing.

I asked Saab about their "multipoint check" as I think it's called and it seems no more thorough than the sort of check thee or me would give a car before buying it, so not worth it.

If Boxer Motors give it the all clear, I'll go for it.