s3 8l apy to bam wireing help


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Sep 3, 2019
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hi i just bent a rod in my apy lump. had a bam one spare with loom and ecu. thought it would be quicker just to swap lumps, ecu and engine harnes.
now ran into a problem... the car starts and drives as should but the fans come in intermitantly. ihnition only needs to be on for this to nappen. ive looked around and cant seem to find anything about this. any help please TIA

What parts of the loom did you use?

What else have you wired in as BAM is wideband so needs a different lambda... plus has EGT, VVT which the APY doesn't... I assume you have an engine control relay fitted else the throttle wouldn't work..

Sounds like a wiring issue... been a while since I did a conversion like this but I'd check the pin outs for differences without knowing which parts of the loom you have used...

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its a full bam engine with all the original sensors n parts. using the engine loom and ecu from the same engine. someone said to cut white wire on pin 6 does this mean anything to you thanks
Did they validate why they thought that needed doing?

If using all the parts then I am not sure what the issue is off hand but its almost certainly an issue with differences in the wiring loom somewhere...

Did you use just the two ECU sections of the BAM loom?

The 14 pin plug that comes off the smaller ECU plugged loom... that connect to your existing 14 pin plug (passenger side inner wing by the side of the battery?

i used loom that comes from the engine goes to a plug near wing (black with purple in middle) think this is te 14 pin plug you mention, then goes upto the right side of ecu if that help...ill go to my garage tomorrow and doulbe check thanks for help so far thanks nick
ill chech the pins match up on the plug near wing think that should be a good start :)
Not personally checked the APY/BAM/AMK or whatever wiring out myself as generally speaking the wideband conversions on APY's are typically just a case of adding a couple of wires and repinning a couple at the ECU... not been involved in one that used a full loom but the assumption is that the wiring from the BAM ECU to the sensors on the BAM engine via the BAM loom should be fine its any connection back to the APY loom you have to be wary of..

I had to re-pin the 14 pin plug when I did my VR6 conversion using the TT 3.2 small plug loom... there were a couple of subtle differences there and IIRC on an APY wideband conversion I think you have to remove pin 61 on the AYP loom if not using EGT or wire directly if you are...

thanks mate... im going check the 14pin plug as i can only assume the differance is in there as im using the bam engine loom and bam ecu so cant see any pin differance in the ecu side as they should be matched (hopefully) thank again nick
Kinda on topic.. Wanting to pin the speed sensor wiring for the 3.2 conversion but have no idea how to strip the male side 14 pin plug. Need to depin and repin but can't seem to understand how this one strips apart
Most in not all VAG plugs have a purpley/pink insert that needs moving over or removing to be able to pin a plug... the big 14 pin plug/socket is the same...

I cannot recall if this is pre or post moving the insert but there is an arrow (top left) which I think indicates direction to lock... if your plug looks like this now then its direction to unlock... you should then be able to depin using relevant tools... this plug was a PITA though to be fair...
Screenshot 2019 10 04 at 165420

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APY and BAM looms are different in few parts. Your problem is that BAM loom that connects to a OEM exhaust gas sensor, now goes on APY loom to Fan control hense the pulsing of fans.
Pull pin 61 and fans stop pulsing
See pics

pin 61 on APY goes to fan control

pin 61 on BAM goes to EGT

I have BAM loom modified to use with APY loom and uses wideband lambda. You can use APY loom, just add the wideband 2 wires extra, rewiere the lambda and then pull pin 61(white cable, dont cut, pull pin of and tape it) so fans dont pulse.
I got all the eletrical drawings if you should need.


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