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Discussion Starter #1
Hi everyone.. thanks to everyone who helped me before.. I was hoping if anyone could throw some light on a problem Im having with my Saab 2002 HOT aero

Suddenly its got very loud when I accelerate, especially in low gears. Also it seems to vibrate a lot! The turbo seems to be working fine, no smoke and in 3 4 and 5th gives power fine. If however I try and accelerate hard in 1 or 2nd it BOOMS and vibrates so much I have to change gear as it sounds terrible!

Also when I change gear the revs seem to stick momentarily then drop, which I have never had before...


Anyone got any ideas, am I in the middle of a turbo failure? Any help greatly appreciated...



Cheers

G
 

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Discussion Starter #2
Me again.. having driven the car a bit more today, I was wondering if a problem with the exhaust could be the issue? Are there any sensors that would fail causing the momentary stick in the revs? I had the mid section replaced but notice it had a slight burble to it a few days ago.

again any help is massively appreciated from you guys as Im a novice with Saabs!
 

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Could be many things. The exhaust plays a part in stabilising the engine, maybe the flexy section has failed. Also look at the engine and gearbox mountings.

If things move about too much the noise and vibration could be from the drive shafts or the engine touching some thing. The lower gears generate more torque on the drive shafts. Twisting the unit further.

But it could also be a gearbox problem as the two lower gears use the same shaft.
 

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Discussion Starter #4
Thanks so much for the reply I will check those. I replaced the midsection a couple of months ago with the flexi joint in so Im hoping that is ok. I get no vibration at higher speed.. its a hard one to describe as it seems to vibrate due to the increased 'roar' when accelerating - perhaps Im not describing it well, its a very deep roar as you build up revs then it vibrates due to the increased noise.

Like I say everything seems to run fine and there's no error or faults coming up ( would they just appear in the sid?)

Could I have 'blown' a pipe off somewhere? Or a tube has cracked?

Sorry for a millions questions I'm hoping I don't have to take it into a garage as its xmas and money is tight and I need to visit people :-( Is there a tell tale sign for exhaust leaks/ issues as it sounds ok when revving it gently when stationary

Thanks again sgould really appreciate the advice.


G
 

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You can try and check an exhaust for leaks by blocking the end with a rag. Make it a thick one, the exhaust will be hot! If yo have a leak you may see where it is from the smoke. If you don't have a leak, the engine will probably stall.. Don't do it for too long and it's not a 100% reliable check, but you may be lucky.

Do check all the inlet pipes for problems - splits or collapse. Does the engine smoke when you get this noise?
 

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Discussion Starter #6
Thanks again for this really appreciate it sgould I will try that tonight and see what happens.

It's really strange it sounds 'rough' when I accelerate kind of like a boy racer with a fat pipe on, but it performs fine. There's no smoke from the engine, although theres a little rattle I havent heard before.. but that could be me looking for problems..

It its pretty quiet when idling, in fact you wouldnt know anything was wrong until I put my foot down...

Thanks
G
 

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Discussion Starter #7
Right here's an update...

I tried the rag in the exhaust, pressure is so good it just kept blowing the rag out with huge force, even when I tried to hold it in.. think the exhaust it fine by the look of it.

Checked the pipes could see any cracked or broken..

On the throttle body is it possible that something is stuck 'open' or wider that it should.. it sounds little like too much air is getting in/ out of the turbo/ into the mix?

I sat with it idling and sounds great, even when revved on the spot it sounds perfect, its just when you drive away and accelerate.


I did think my manifold was cracked then like a complete fool realised they are made that way with the splits in between the pipe fittings... DOH.. spot the noob


anyone got any ideas... HELP!
 

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Right here's an update...

I tried the rag in the exhaust, pressure is so good it just kept blowing the rag out with huge force, even when I tried to hold it in.. think the exhaust it fine by the look of it.

Checked the pipes could see any cracked or broken..

On the throttle body is it possible that something is stuck 'open' or wider that it should.. it sounds little like too much air is getting in/ out of the turbo/ into the mix?

I sat with it idling and sounds great, even when revved on the spot it sounds perfect, its just when you drive away and accelerate.
I did think my manifold was cracked then like a complete fool realised they are made that way with the splits in between the pipe fittings... DOH.. spot the noob
anyone got any ideas... HELP![/b]
If you say you have a problem in 1 and 2 and that in 3, 4 and 5 all ok before I would say it's the gearbox, that I first looked at when such a symptoms
 

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Discussion Starter #10
thanks again guys really appreciate the answers. I will have a good check and see if the mounts are failing and see if I can get someone to check the gearbox.

just as side note, Ive noticed my fuel consumption has suddenly shot thru the roof.. I think Im only getting about 14 to the gallon!


thanks again

G
 

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That makes a lot of choices too. Maybe the air meter is broken and the mixture is all wrong. Same thing as a split pipe.

I don't have any info for the 9-3, but I believe that you can check the resistance across the terminals of the meter.
 

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Discussion Starter #12
Me again.. well Ive been trying everything recently and wondered if Im getting any closer.

The car is running fine, its just this 'over boosting' type issue which is more noticeable in 1st gear plus revs stick momentarily as you change gears as if theres too much 'boost?' being applied as standard.

Basically I cant accelerate as long/ hard as I used to as it seem to 'clog' the engine and I get this deep roar ultimately with a heavy vibrating if i go to far, which sounds like the exhaust moaning at there being too much boost/ air flow ( could be some exhaust issue or some valve not opening correctly - theres no leaks in the system BUT it did have a new mid pipe on shortly before this started.

I'm going to have one last look over the engine and if I cant find anything looks like I have to take it to a dealer..

So the question I'm getting round to...

If the Boost control valve has gone, would it cause something like this, or if the wastegate was faulty? If the throttle body was at fault or somehow 'slipped out of position' would this cause a problem ( I ask as all this started when I accelerated too quickly from a cold start and it never settled down as if something had blown or stuck on/ off open/ closed

Im running fine in higher gears, but then I done put my foot down much now..

so far Ive checked engine mounts, all pipes, oil, turbo (for signs or noises that could indicate its gone) - everything seems fine.



Appreciate any advice before I get stung at a garage. :-(
 
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