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PostPosted: Mon Feb 11, 2019 9:47 pm 
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Joined: Mon Mar 28, 2016 11:31 am
Posts: 80
Car Model: '95 9000 Aero
Hi everyone

My 9k is acting up again, just when I thought I had everything fixed.

It's showing the following symptoms:

The idle has trouble settling - sometimes it will stay at 1200-1400 RPM for tens of seconds, when coming to a stop, clutching out during maneuvering or just revving the engine a bit in neutral. When moving, the idle sometimes won't go down at all, e.g. I'm in second gear at 30 km/h, so like 1500 RPM, and when I go off the gas the car will just keep on pushing until I go on the brakes. The revs also fall mostly much slower than they should.

Basically, it feels like it's running rich or has a vacuum leak somewhere. My carbed motorcycle behaves exactly the same when the choke is on. I have not been able to find any actual vacuum leaks and all vacuum hoses are pretty new. However, there is a very suspicious hissing noise coming from the fuel pressure regulator - the diaphragm seems to be fine though (judging from a "suck test")... I've ordered a new one cause they're nice and cheap, it should arrive some time this week.

The IAC valve is out of the question as my car is a TCS model and doesn't even have it in the first place. I've already tried recalibrating the throttle body (which is rather new - about 15k km on it).

I've also cleaned the ECU ground contact thoroughly, didn't help. Does anyone have an idea what else this could be? And/or how I might put my Tech II to use to diagnose the issue? Else I'll have to whip out T5Suite, which would probably mean hours of standing next to the car with my laptop... Could this be the O2 sensor on its way out? What makes me doubt that is the fact that the car behaves like this already from a cold start - as far as I know, a cold engine will be running in open loop mode, so the O2 sensor couldn't possibly cause these symptoms on a cold engine, no?

Thanks in advance,
Georg


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PostPosted: Mon Feb 11, 2019 10:45 pm 
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Joined: Mon Feb 19, 2007 4:12 pm
Posts: 8587
Location: Portsmouth
Car Model: 96 V4 & 9-3 Turbo-X
Check the check valves on the bulkhead and the wing.

They both connect to the manifold and should be using the vacuum to hold the emergency throttle out of the way and limit boost by keeping the dump valve open when in limp-home mode respectively. If they were leaking it could cause the hissing noise you're hearing.

Also check the one-way valve on the breather pipe, and the breather connection to the cam cover.

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PostPosted: Tue Feb 12, 2019 12:08 am 
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Joined: Wed May 12, 2004 9:46 pm
Posts: 14903
Location: Mulbarton,Norfolk
Car Model: TTid's only now :-(
air intake leak most likely.

Check pipes and bungs after throttle body (including under TB)

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PostPosted: Tue Feb 12, 2019 10:52 am 
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Joined: Thu Oct 08, 2009 10:19 pm
Posts: 4459
Location: Island of Sodor
Car Model: The Pizza Taxi
Also check the Coolant Temp Sensor.

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PostPosted: Tue Feb 12, 2019 1:36 pm 
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Joined: Sun Jan 26, 2014 9:41 am
Posts: 3304
Location: Royal Tunbridge Wells
Car Model: '03 9-5 2.3 Vector Auto Estate
I had something similar on a non TCS 9k and it was the MAP sensor. Presumably with TCS you still have that?

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'03 Saab 9-5 2.3t Vector Estate Auto Noob Stg 1
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PostPosted: Tue Feb 12, 2019 4:59 pm 
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Joined: Mon Mar 28, 2016 11:31 am
Posts: 80
Car Model: '95 9000 Aero
Thanks for the replies, I'll check all of those and report back!

One of the bungs going into the manifold is indeed a bit loose (can be turned and pulled out by hand if you grip it real hard), but that's been the case for a long time and has never caused problems until now. I'll glue it in tonight anyway! Luckily I still have a new, unused MAP sensor waiting to be installed, so that's another easy thing to check.

I really hope I can get this thing running right again!


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PostPosted: Wed Feb 13, 2019 10:52 am 
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Joined: Mon Mar 28, 2016 11:31 am
Posts: 80
Car Model: '95 9000 Aero
I replaced the MAP sensor yesterday and can't decide if it's gotten much better... Subjectively it seems a bit more stable now, but still not as nice as I'd like, on startup it still oscillated a bit for some minutes. And the hissing noise is making me think there's a small vacuum leak somewhere around the fuel pressure regulator - when I touch the regulator/press on it, it changes pitch or disappears entirely. Unfortunately, the regulator I ordered turned out to be the wrong model (fits for late 9000s and 9-3/9-5) so I'll have to order another one. Still haven't glued up the bung either.


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PostPosted: Thu Feb 14, 2019 8:28 pm 
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Joined: Mon Mar 28, 2016 11:31 am
Posts: 80
Car Model: '95 9000 Aero
Well, might as well triple post at this point...
I took another test drive today, the issue is definitely still here. I glued the bung tight, but it didn't make a difference - sometimes the idle will rest at 1100+ when warm for 10-20 seconds, and it still "pushes" too soon with closed throttle. The hissing sound seems to almost disappear when I press on the fuel pressure regulator, but I haven't had the chance to have someone else rev the engine for me yet so I can't say if that fixes the actual problem, or if I'm just hearing the fuel return flow. There's no valve or plug where I could hook up a pressure tester, so I don't know what fuel pressure I'm getting... I'll have to do some checking with the Tech2 over the weekend.


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PostPosted: Mon Apr 01, 2019 6:34 pm 
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Joined: Mon Mar 28, 2016 11:31 am
Posts: 80
Car Model: '95 9000 Aero
Well I was definitely wrong about negative tank pressure being the cause. It's still happening, and I keep opening the tank cap. Sometimes however, it completely disappears for a while - like when I tried to find the problem with T5suite yesterday. I'm stsrting to think it might be a bad joint in the ETS/TCS ecu - the intermittent nature of the issue pretty much rules out a mechanical problem. Plus I've read an account of somebody with the same issue who fixed it by swapping that ECU for a new unit. So I'll be opening that guy up in the near future to see if I can find any cold joints in there.
I also noticed that (as would be expected) it's much worse when the A/C is on - it's as if the load compensation didn't work correctly.

Edit: this is actually in the wrong thread... I was referring to the problem I was having here: viewtopic.php?f=2&t=180956

Basically sometimes (most of the time nowadays, it would seem) the idle dips after giving the car some gas, or when coming to a stop with the clutch disengaged. When there's some additional load on the engine, e.g. from turning the steering wheel at low speeds or from the A/C, it's much worse and sometimes the engine even dies. New MAP sensor definitely didn't fix this, for a time I thought it was negative pressure in the tank but that was a fluke. So now my only lead is that it might be the TCS ECU...


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