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PostPosted: Sun Jul 08, 2018 8:37 pm 
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Joined: Sun Aug 21, 2016 3:48 pm
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Location: Sussex Coast
Car Model: 9000 AERO, C900T16S, C900i
Since swapping the Abbott ecu with t5 apc and bleed valve for a Jules mapped ecu and brand new t7 apc I've been struggling with an intermittent fuel cut on my 9k Aero, the apc is working as it reduces boost in 1st gear as per original spec but occasionally cuts on full boost in 3rd,4th and 5th it also happened in 2nd yesterday.

So far I've checked the vacuum hoses and unions on the manifold, looked for boost leaks, changed the map sensor and checked that the actuator isn't sticking. Base boost appears ok.
I'm hoping that someone can point me in the right direction of what to check/where to look next. TIA


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PostPosted: Sun Jul 08, 2018 10:49 pm 
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Location: West Sussex
Car Model: 9000 Aero......GM900i
Are you using the stock fuel pump?
I was having big boost cut but a new Walbro 255 pump cured the fueling issue.

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PostPosted: Mon Jul 09, 2018 8:26 am 
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Location: South Wales
Car Model: 900 SE Stage 3
It's not particularly unusual when pushing boost up to 1.35-1.4 bar as you only have a tiny amount of headroom between requested boost and the fuel cut off limit. (1.54 bar)

Easiest solution is probably to switch to a 3 bar map sensor and raise the fuel cut to say 1.65 bar giving you more headroom.

Another quick alternative is to adjust the size of the restrictor in the C port on the APC valve. Going to far here will really reduce the rate of climb of boost and the peak. (removing the restrictor altogether will show you the effect at it's strongest.

The only other alternative is to get the boost control tables tweaked in the map to suit the way the car behaves.

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PostPosted: Mon Jul 09, 2018 9:02 am 
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Joined: Wed Jul 29, 2009 6:21 pm
Posts: 11615
Location: All over town.
Car Model: Mapped S60 D5
Nick71 wrote:
Since swapping the Abbott ecu with t5 apc and bleed valve for a Jules mapped ecu and brand new t7 apc I've been struggling with an intermittent fuel cut on my 9k Aero, the apc is working as it reduces boost in 1st gear as per original spec but occasionally cuts on full boost in 3rd,4th and 5th it also happened in 2nd yesterday.

So far I've checked the vacuum hoses and unions on the manifold, looked for boost leaks, changed the map sensor and checked that the actuator isn't sticking. Base boost appears ok.
I'm hoping that someone can point me in the right direction of what to check/where to look next. TIA


It could be just adapting to the new setup. Give it plenty of adaption runs and see if it still does it. Have you got a boost gauge plumbed in just to see what it's doing? Easiest solution would be just to get Jules to remove the fuel cut as long as it isn't spiking massively over (again you can monitor this with a boost gauge)

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PostPosted: Mon Jul 09, 2018 6:25 pm 
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Joined: Sun Aug 21, 2016 3:48 pm
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Location: Sussex Coast
Car Model: 9000 AERO, C900T16S, C900i
Thanks, I don't really want to reduce the boost. No gauge other than standard but will be fitting an aftermarket one soon. I presumed that the fuel cut would of been raised when the map was loaded?

Out of interest what is the "safe" boost limit on standard injectors and turbo etc?


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PostPosted: Mon Jul 09, 2018 6:43 pm 
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Location: South Wales
Car Model: 900 SE Stage 3
I'd say the safe limit on the TD04 is around 1.6 bar for a short duration peak in the mid rpm range. (2.5-3.5k) Hitting 1.6 bar beyond that rpm will push the turbo outside it's comfort zone, it won't break it but it'll really heat up your inlet. The stock fuel system won't have much headroom left either. You should be able to comfortably push 1.4 bar out to 4.5k, 1.2 out to 5.5k and around 1 bar at the limit.

To get get more than the 1.54 bar fuel cut limit, you'd need to replace your current 2.5 bar MAP sensor with a 3 bar MAP sensor. The ECU map would need to be adjusted to suit it with a raised fuel cut. (A 3 bar sensor can support up to 2.04 bar fuel cut)

Filathome is right in that the ECU will adapt itself as much as it can, but there are limits to these self trimming parameters in the map and if you disconnect your battery, it is all lost.

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PostPosted: Tue Jul 10, 2018 6:26 pm 
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Joined: Sun Oct 15, 2006 7:02 pm
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Location: Reading, Saabshire
Car Model: Merc A220d AMG 7sp DCT
Kei wrote:
It's not particularly unusual when pushing boost up to 1.35-1.4 bar as you only have a tiny amount of headroom between requested boost and the fuel cut off limit. (1.54 bar)

Easiest solution is probably to switch to a 3 bar map sensor and raise the fuel cut to say 1.65 bar giving you more headroom.

Another quick alternative is to adjust the size of the restrictor in the C port on the APC valve. Going to far here will really reduce the rate of climb of boost and the peak. (removing the restrictor altogether will show you the effect at it's strongest.

The only other alternative is to get the boost control tables tweaked in the map to suit the way the car behaves.



Exactly this. ^^^^
The rising boost rate is far too fast for the aging Wastegate. I had this also with Jules high end map for the stock turbo.
On mine i found completely removing the plug in the C port worked perfectly. It just sat at 1.4 bar boost all the time, no matter how hard or quickly i stamped on the loud pedal.

You should ideally have a large downpipe ?. Also remove the snorkel from the air filter box, as its designed to throttle air flow.

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PostPosted: Tue Jul 10, 2018 11:05 pm 
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Joined: Sun Aug 21, 2016 3:48 pm
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Location: Sussex Coast
Car Model: 9000 AERO, C900T16S, C900i
A lot of food for thought here. What actual effect does removing the c port restrictor have? And it's on a standard dp with decat and 2.5" stainless single box system.


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PostPosted: Wed Jul 11, 2018 12:27 pm 
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Location: Queenborough, Kent
Car Model: 9k, 9-5 Aero & a Jaaag
'C' port is the "Compressor" connection - i.e., the pipe which connects to the turbo compressor housing. The APC valve/solenoid can route this air back to the inlet side ("R", or Return connection), or to the wastegate actuator ("W" connection). My understanding is that removing the restrictor means that more air reaches the wastegate actuator - and quicker - meaning it can start to open (and thereby bleed off some of the boost) sooner, thereby reducing the size of the boost spike.

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PostPosted: Wed Jul 11, 2018 7:03 pm 
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Location: Reading, Saabshire
Car Model: Merc A220d AMG 7sp DCT
Nick71 wrote:
A lot of food for thought here. What actual effect does removing the c port restrictor have? And it's on a standard dp with decat and 2.5" stainless single box system.


If your going over 1.3 bar boost i would highly recommend getting a 2.5", or 3" downpipe.
You will be absolutely floored by the power difference. It completely changes the power and torque curve.

The factory 9000 downpipe is one of the worst designed in all automotive history.
Gasses come out of turbo at Warp9, and hit a wall, then get redirected down.

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92 9000 CSE 2.0T TD04, Wasaabi II
08 Vauxhall Astra 1.8 Elite.


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PostPosted: Thu Jul 12, 2018 7:46 am 
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Joined: Sun Aug 21, 2016 3:48 pm
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Location: Sussex Coast
Car Model: 9000 AERO, C900T16S, C900i
Paul Taylor wrote:
Nick71 wrote:
A lot of food for thought here. What actual effect does removing the c port restrictor have? And it's on a standard dp with decat and 2.5" stainless single box system.


If your going over 1.3 bar boost i would highly recommend getting a 2.5", or 3" downpipe.
You will be absolutely floored by the power difference. It completely changes the power and torque curve.

The factory 9000 downpipe is one of the worst designed in all automotive history.
Gasses come out of turbo at Warp9, and hit a wall, then get redirected down.


A decent down pipe is on the list of work that I want to do to the car, the most pressing thing on the list is to fit the LSD into my spare gearbox then fit a new clutch along with the rebuilt gearbox and replace the engine mounts at the same time.
I may mount a flywheel up in the lathe and lighten it a bit so it can be fitted at the same time any idea of how light to go?


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PostPosted: Thu Jul 12, 2018 9:39 am 
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Joined: Wed Jul 29, 2009 6:21 pm
Posts: 11615
Location: All over town.
Car Model: Mapped S60 D5
Nick71 wrote:
Paul Taylor wrote:
Nick71 wrote:
A lot of food for thought here. What actual effect does removing the c port restrictor have? And it's on a standard dp with decat and 2.5" stainless single box system.


If your going over 1.3 bar boost i would highly recommend getting a 2.5", or 3" downpipe.
You will be absolutely floored by the power difference. It completely changes the power and torque curve.

The factory 9000 downpipe is one of the worst designed in all automotive history.
Gasses come out of turbo at Warp9, and hit a wall, then get redirected down.


A decent down pipe is on the list of work that I want to do to the car, the most pressing thing on the list is to fit the LSD into my spare gearbox then fit a new clutch along with the rebuilt gearbox and replace the engine mounts at the same time.
I may mount a flywheel up in the lathe and lighten it a bit so it can be fitted at the same time any idea of how light to go?


Unless you have means of balancing the flywheel post machining I wouldn't recommend it.

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98 9K 2.3
92 9k CD 18t
99 9-3 19T
00 9-5 Aero S3
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PostPosted: Sat Jul 14, 2018 6:23 pm 
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Joined: Sun Aug 21, 2016 3:48 pm
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Location: Sussex Coast
Car Model: 9000 AERO, C900T16S, C900i
I rigged up a Boost gauge today, generally peak boost is around 1.4bar but when it over boosts it hits over 1.6bar so guess that confirms that it's fuel cutting. The shame is I really like the 1.5+bar performance :D


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