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Discussion Starter · #1 ·
Just thought i would offer some help here as it seems important considering modifying is important on this forum.

When you have the car either mapped, modified or anything to do with removal of power (battery disconected etc etc) you must do the following.

Turn the car over with the key,

DO NOT REV THE ENGINE IN ANY WAY !

Let the car idle for 10 minutes.

Reason for the above is the signal taken off the ecu from the maf unit which after power is removed is to set the fueling/air setup in th dme.

This signal plays a part into how much fuel is added @ idle so when you rev the car even slightly the air passes quicker and hence is colder making the ecu set to add slightly more fuel causing overfueling and less power.

This can be noticable after power is removed from the battery, ecu is flashed via mapping, ecu is reset with the likes of vag-com.

We did some testing yesterday with a difference in power on a mapped 1.8T 2002 of 196hp with the car run after the remap and then 219hp when the car was left to idle for 10 minutes after an adaption reset.

Again, the same today with a 1999 1.8t which was mapped via traditional methods which although not put on the rolling road ran noticably smoother after the adaption reset and 10 minute idle over the way it run when revved after the inition remap.
 

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I assume the ECU would adapt afterwards anyway, so in the long run you will see no difference?
This is what I'm thinking. Might work initially, but the ECU is constantly assesing the data it receives.

Also would the car need to be warm or cold for this proceedure.

Not convinced so far, but open to be prooved wrong. I'd want to see the same car dynoed again a week later.
 

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Discussion Starter · #5 ·
The ecu does not adapt the reading at idle so you would always slightly overfuel if you didnt go through the process correctly.

the ecu only adapts when under load and at idle your not under load.
 

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Jay,

Is this the closed loop state that the car operates in until it gets to about 1500rpm (not sure exactly what it is on the golf)

the emissions control state.If that makes any sense ?If so i get what you mean.
 

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Discussion Starter · #9 ·
In a way yes.

What it does is to read the signal for the first few minutes and sets to a set signal which is then not altered.

I think it is too 1240rpm which allows room for auto-choke.
 

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So basically running the car for 10 mins at idle will allow the ecu to set the fueling from 0 to 1240 rpm then driving through the gears at different revs then allows the ecu to adapt fueling and timing from 1241 rpm to redline?

0-1240 rpm being idle speed and 1241-redline being normal operation state.
 

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Discussion Starter · #11 ·
exactly yes.

(although i am not 100% sure on the exact rpm at idle the cut-off is but it is around the 1240rpm)
 

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Think this may of happened to mine after I fitted an 80mm cold air feed....(had to remove the battery)...since then it does seem to smell pretty strong of fuel fumes on tick over.....could this be the cause...?????....prob only let car idle for 5mins max after I fired the car up?????

better carry out the above reset and see if it sorts it out.......
 

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Discussion Starter · #13 ·
yes this is highly possible.

dissconect the battery for 20 minutes before reconnecting then leave idle for 10 mins.
 

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I guess that at the point you leave closed loop state (0-1240rpm) you
will be running rich when the ecu takes over the fueling and timing
(>1241rpm).
 

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yes this is highly possible.

dissconect the battery for 20 minutes before reconnecting then leave idle for 10 mins.
Will do this today and see if it sorts it out.....great info...many thanks.....[:D]
 

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Discussion Starter · #17 ·
I guess that at the point you leave closed loop state (0-1240rpm) you will be running rich when the ecu takes over the fueling and timing (>1241rpm).
This is exactly correct, if your rich at idle your rich at higher rpm/load.

Running rich loses power.
 

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yes this is highly possible.

dissconect the battery for 20 minutes before reconnecting then leave idle for 10 mins.
Will do this today and see if it sorts it out.....great info...many thanks.....[:D]
Also would I have to carry out TB reset too....(ie turn key to last postion door open etc?????)
 

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I would assume this also applies to diesels?

If so this procedure was not followed when my car was remapped. They fired it up and ran it on the rollers. Maybe I'll give it a go, no harm done if there is no change.
 

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I've read this thread with some interest and more than a hint of scepticism.
It may well apply remapped cars or some engine controllers but not all.

Out of interest I've checked the official VAG procedure for the 170 V5
(AQN) and it details a precise procedure to be followed after any
voltage supply interruption to the controller ie battery removal.

Briefly, the ignition has to be turned on for 10 seconds and then
turned off, then a TBA is performed and finally an idling check. The
idling check involves reading display group 54 in "basic settings".
 
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