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1

Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by fka on 13 July 2020, 09:12:31 PM »

Again it's been a while since I tried the bolt mod on my 9-3 (I ended up removing the hose highlighted in Will's pic as it's a slightly more elegant solution). What you did is probably correct, assuming the boost leak is due to a failed non-return valve on that line to the EVAP system.

The APC is normally open (C port to the W port) - i.e if it's not working at all (When on boost it should be diverting the pressure from the compressor away from the wastegate, to the return port) you'll get base boost.
As you know, the signal to it is PWM, the higher the PWM number on openSID the harder the APC (and ECU) are working to to try and divert pressure away from the wastegate. You'll see PWM hit 980 when you floor it and then it should slowly level off. If you're not achieving MREQ and PWM stays at 980 then the APC is incapable of controlling the actuator/ achieving target air mass . Which could be a weak actuator, or at higher target air masses - that the return port is too restricted or the the C port not restricted enough.. or a boost leak..

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Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by carrera on 13 July 2020, 08:32:15 PM »

I really need to get my head around how it all works.

Yesterday I was reading other threads for suggestions, I'm fairly sure one had contributions from Karl Noobtune, while the other was over on Saabcentral, so was just following instructions really.

The illustration above is one I recognise, I thought that is what I had done, but I am not so sure now.

It seems there are any number of bolt mods too 

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Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by fka on 13 July 2020, 08:21:01 PM »

The "APC" / T7 control valve on the top of the cobra I have not swapped, but I did remove the top pipe and block the connections with a bolt on that pipe and the cobra.

It's been a while since I've looked at one but isn't the top port the return, going to the cobra? You'd need to remove either the collector (bottom, that goes to the compressor housing) or wastegate (middle, that goes to the actuator).
Then in theory you should hit overboost fuel cut when you give it some welly.
0.55bar is close enough to be base boost.

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Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by sgould on 13 July 2020, 05:47:53 PM »

The bolt mod on the APC is a bodge that tries to mimic the removal of the second EVAP non-return valve.  Saab removed the second valve for 2006 onwards.  It won't improve things if the remaining valve is leaking...

the picture shows the pipe to remove.

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Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by carrera on 13 July 2020, 03:27:24 PM »

 

So many things with similar names where the descriptions people use are different to Saab WIS. I'm easily confused.

I was talking about the control valve on the bulkhead, that manages over run situations and according to WIS can cause low Mair if it is failing.

The "APC" / T7 control valve on the top of the cobra I have not swapped, but I did remove the top pipe and block the connections with a bolt on that pipe and the cobra.

No difference so I assume it's working correctly.

I need to re-remember the bolt mod I saw on Saabscene about 15 years ago with the one way valves, one of them is on the right hand wing. I had that problem on the blue car. I thionk that's more related to the EVAP part of the system, but it has the same effect

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Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by fka on 13 July 2020, 02:52:42 PM »

Are you talking Bypass Control Valve or Boost pressure control valve, APC? I meant the APC.

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Classic Saab 9-5 (MY 1998-2010) / Re: 2.2TiD - potential upgrades and remaps?

« Last post by Audax on 12 July 2020, 06:14:44 PM »

That is something I have noticed. Whereas a petrol car is thirsty for the first 5 minutes or so, the diesel really takes time to get efficient, probably 15-20 minutes before it is giving good mpg, even when going straight onto a dual carriageway.

Yes, it's because they take ages to heat up, a common complaint of 1.9 diesel owners was that their car was always cold when driving to work but when asked they wouldn't be commuting more than 5 miles to work and as a result also got poor fuel economy.

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Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by carrera on 12 July 2020, 04:30:58 PM »

There was not enough room to chuck the spare BPCV in with the loom so I removed the rivets and swapped it over. No change, so my BPCV is good.

I removed the MAF in case there was a blockage, and noticed that the lower rubber section where the outlet pipe connects to the cobra was bent over. Ah, potential for unmetered air. Fixed that, mReq increased to 1200 but Mair remained at 900. Little tease, more potential, but no delivery.

I also put an airline onto the cobra having blocked off the intercooler pipe to the plastik intake pipe. I didn't detect any leaks.

More thinking required, and I probably need to learn how the T7 valve works

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Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by carrera on 12 July 2020, 07:25:11 AM »

Well that's encouraging as that's exactly the areas I was thinking about. I tried to bypass the BPCV with no difference, in fact I did go to swap it out and then found it is help onto the metal plate by rivets not screws. Why, oh why oh why Saab ?

I might just chuck the whole spare engine loom into the engine bay for a test

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Classic Saab 9-5 (MY 1998-2010) / Re: Graphite Green 9-5 Aero rescue

« Last post by fka on 11 July 2020, 11:58:10 PM »

must be a boost leak somewhere or something's opening that shouldn't. BPCV mechanically not working despite PWM appearing to be ok?