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Hi. I have an 3b engine in my s2, Broadbandlambda mounted but not connected to ecu.
When I start the engine it goes lean under warmup , ( 15,5- 16,5 -1 )
After 5 min on its normal, 14.7-1. Tried to change the temp sensor on head but no luck !? Anyone ?
ECU does not use narrowband for a while... after it's warmed up, it just starts to run closed loop.
If you see very lean mixtures, it can be due to the following:
1. Vaccuum leak.
2. Leak between MAF and Turbo.
3. Bad software in ECU.
If you have lean mixture when your engine is cold, even when accelerating, then that can mean a small leak, which reduces in severity as components expand under heat.
I would suspect air leak too... Lambda probe cannot be used until it is warmed up so ECU runs open loop for a while with a cold-start sequence. If anything it should run a little rich while cold, but not looked at this specifically on a 3B before.
With a small air leak the Motronic adaptation will correct things once it starts to run closed loop. You can get a view of how much the ECU is adapting by looking at ECU Group 0 in VAGCOM - fields 8 & 9 from memory (or 9 & 10)... short term and long term adaptation parameters... If the ECU has to adjust too much for lean or rich running in closed loop then it will throw up a fault code relating to mixture and/or adaptation.
every time when I have boost leak it I can see it on boost gauge or on dash , it' must be 0,2 at hot engine or 0,3 when engine is cold, or 0,4 is still good if the cilinder head are little bit old.
and must go in boost very well , for stock 3b 0,9 bar or 1,9bar on dash...
every time when I have boost leak it I can see it on boost gauge or on dash , it' must be 0,2 at hot engine or 0,3 when engine is cold, or 0,4 is still good if the cilinder head are little bit old.
and must go in boost very well , for stock 3b 0,9 bar or 1,9bar on dash...
those are simptoms of boost leak.
Dont understand this ....what.. how?
Thanks guys ! I realy appreciate all help I get here! Will test more tomorow ... Will come back with more info..
Tested all hoses and clamps with startboost spray to see if it would change in idle, found nothing .
test drove it and its seems to be ok when warm . 1.3-1.2 bar but drops a bit ( wg feder i think) FULL THROTTLE = 11,8 , 12-1
ON 3-4 GEAR.. hm....
pressured tested system , no leaks.... Starting engine, afr drops to 13.5-1 . 1-2 minutes later 15.5. 5 min. later 14.7,14.8-1 steady. 3 gear 1.1-1.2 bar , 12-1 afr... hm...
Hello again, Havent used the car for a while but tried it this weekend.. After a while I stopped the engine , 5 minutes later , no start , I could not hear the fuelpump ! DEAD ! Brought it back home , next day ignition on , pump starts , engine starts !!
Shut ofn engine , ignition on again , fuel pump runs constantly !!
Fuelpump does not stop when only ignition is on !.. And it runs lean on warm up ! ( I think the afterrun pump started also on cold engine )
I tried an other fuelpump relay , no luck....
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3b lean on warmup...
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