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Gtir Motorsport club » General Discusion » Gtir related Discussion » running lean

running lean

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1 running lean on 18th July 2017, 7:16 pm

allbeast


hi guys
I wonder if anyone can help me with my lean problems ?
first of all my spec
pulsar gtir pretty much stock apart from a garrett gt2860 rollerball turbo
bogdan elbow , 3" down pipe and 2.5 back (no cat) AS 1991
and aftermarket air filter standard ecu . That's about it


sorry for rant
so my problems
I live in Nottingham and went to bobs for a check up and as follows . we set the timing to 18 deg as was a bit out . reset tps did the first run and was running out at 13s on afr at boost so we changed the following
fuel pump , fuel filter in tank and out , checked volts at pump 11.9 ,checked fuel lines all ok , pressure regulator, fuel rail ,plugs, maf , air filter , 540 injectors ,pressure test even changed ecu and still the same . After all the hard work , time , 24 hours ,effort that bob and lee put in we were all scratching our heads with the same results

so if anyone anyone can hep please let me know cheers dave

2 Re: running lean on 18th July 2017, 7:31 pm

johnny gtir

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moderator
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You try a different Ecu. 11.9 at pump did you try direct feed to pump ? What make injectors ?

3 Re: running lean on 18th July 2017, 7:42 pm

allbeast


tried ecu
ran 12v direct
standard 444 injectors
still same

4 Re: running lean on 18th July 2017, 9:15 pm

mike74

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I had this on my last R...was clogged fuel injectors. Got them rebuilt and cleaned and they were as good as new!

5 Re: running lean on 18th July 2017, 9:47 pm

Mr B

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gtir technician
gtir technician
check fuel lines for blockage with air nozzle, stick a fuel pressure guage in & run a scope on the pump and check voltage, current draw over motor commutator pulses, if that A1 healthy and fuel pressure does stay solid and fuel lines not partially blocked then look at ecu water temp signal, lambda and maf wiring and maf signal ecu actually getting, wouldn't rule out injectors unless test them, can do relative injector test which basically balance tests flow between all 4 while on car, swapping parts can lead you in wrong direction as many times swapped part still not A1 .

6 Re: running lean on 18th July 2017, 10:20 pm

allbeast


we put a fuel reg reg on it and it held pressure and a 12v direct feed from a jump pack and multi metre at 12 v . Changed injectors for bigger ones but still same trying to get hold of new lambda at the mo
she is driving me mad don't know what else to do bom

7 Re: running lean on 18th July 2017, 10:56 pm

Gostek

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Events Organiser
Events Organiser
I've used this lambda few times and it works fine (I assume you're after narrowband)

http://www.ecolambda.co.uk/main/ecosale/price.pl?item=250-23880

But tbh lambda is only controlling fueling till circa 3k revs after that it goes in to open loop.

I know it might sound stupid but is your afr gauge calibrated ok? I've had hell of a problem lately with innovate.


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8 Re: running lean on 18th July 2017, 11:20 pm

allbeast


it was on bobs rolling road he ran a car after mine with previous print out and that was fine so mine we think is at fault

9 Re: running lean on 18th July 2017, 11:50 pm

Mr B

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gtir technician
gtir technician
allbeast wrote:we put a fuel reg  reg on it and it held pressure and a 12v direct feed from a jump pack and multi metre at 12 v . Changed injectors for bigger ones but still same trying to get hold of new lambda  at the mo
she is driving me mad don't know what else to do bom
You get pressure but what about flow, fuel lines want physical checking that no flow restriction.
I would also scope the injector pulses to be sure signals and amp draws seem normal enough . All earthing could do with checking . clean and flow testing injector set not bad and can also fit better flowing to hottest/leanest cylinder which never bad practice.
fuel pump fuel pump wiring, fuel injectors and maf most common areas for lean under boost, I had people swap pumps and say it not pump related but quality pump or proper pump wiring fixed it, MAFs PITA too, I got spare which did seem perfect but when came off shelf for swap a part diagnosis it was junk ... obviously bob in better than average scenario for used parts but can't trust results from swapping stuff as don't conclude much, you got get readings etc to conclude what good and get direction to what likely not good .

10 Re: running lean on 18th July 2017, 11:52 pm

Mr B

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gtir technician
gtir technician
double post error ...



Last edited by Mr B on 19th July 2017, 12:58 am; edited 1 time in total

11 Re: running lean on 19th July 2017, 12:32 am

allbeast


ok will change the fuel lines in the morning if nothing else I will know they are new
cheers

12 Re: running lean on 19th July 2017, 8:16 am

mike74

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Also check the inlet tube & its connection to the turbo for any leaks. If there's a leak on this side the turbo will draw in unmetered air and lean out. Could be something as simple as the original dump valve return connection leaking on that tube....hopefully! Smile

13 Re: running lean on 19th July 2017, 1:27 pm

GTI-R US

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Management
Management
Dave the only possible thing i could think was causing this issue was either incorrect inlet valve timing which we checked and all was fine so wasnt that.
The only remaining thing which also is causing other issues is the 'throttle bodies'
High idle.......this is why timing was backed off to 15degrees
Can clearly see the idle stop screws have been tampered with also to slow the idle speed
Plus the idle control screw has been turned right in to the max

So i would say that when the bodies are open that air is being drawn in through the linkages which is messing with Afr's as your ecu will not be able to monitor this.

Also its not the lambda sensor as this works on open / closed loop system........Basically after around 2k rpm the afm monitors airfliow and ecu adjusts accordingly


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14 Re: running lean on 19th July 2017, 3:44 pm

allbeast


Totally agree with you bob was just plucking at straws with lambda sensor
I have replaced that dodgy hose from turbo to inlet hose ( the one with the 2 joints in ) so hopefully that will help
Once again I can't thank you enough for all you're time you and lee put into the car you're a legend

15 Re: running lean on 19th July 2017, 4:49 pm

Spark plug spike

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My running lean issue under boost turned out to be the gasket between the turbo and the air feed pipe leaking? Maybe worth checking it?

16 Re: running lean on 19th July 2017, 5:06 pm

allbeast


Cheers mate will probably change that too
Every little helps

17 Re: running lean on 19th July 2017, 7:15 pm

Mr B

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gtir technician
gtir technician
defo worth checking all joints between maf and comp housing .
looking at injector duty when on RR at time of lean under boost should give clues as if seems responding in increased duty you can conclude maf measuring air and it fuel side, if duty don't increase sensibly it would point towards air flow measure side of things .
hopefully it simple cheap fix and find it soon, stay calm and good luck ...

18 Re: running lean on 23rd July 2017, 4:20 pm

allbeast


cheers mr b
changing all hoses with new clamps at mo so fingers crossed

19 Re: running lean on 23rd July 2017, 4:34 pm

Mr B

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gtir technician
gtir technician
As bob points out throttle bodies been messed with and likely linked to at least one issue it maybe worth pulling them off for inspection and potentially looking for replacement set if they well worn and tampered with ,

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