This wont apply to many of the forum users as the Mk5 rarely needs the ECU to be removed to be tuned, however I am aware that there are many members with other cars that this may apply to so I thought I would post this so that people understand the process and what to watch out for if they ever own a car with the new EDC17/MED17 tricore ECU system.
Heres a bit of background behind these systems:
http://www.dyno-tuning.co.uk/antiTuningRemaps/The ECU needs to be removed and the case opened to allow you to put the ECU into boot mode so that you can read from and write to the internal or external flash memory to alter the software to 'remap' the ECU. This is where the story started last Saturday....
Customer brought in a Fabia VRS 1.4 TSi for datalogging and dyno testing as he was concerned his map wasn't right, his concern was well placed, Map was requesting 2700mb of boost (safe level of the turbo is a lot lower than this) which caused the wastegate demand to be at pretty much 100% even under low load conditions, EGT's were about 120 degrees higher than we would like to see and AFR under load was 12.8-13.2 (ideal should be 11.2-11.5).
The options were to flash to stock or flash with alternative software (customer didnt want to return to the original tuners for more work) and after a discussion he chose to use Revo software, time to remove the ECU and open it up for bench flashing, which is a complete pain as they are secured in place with a security cage with shear bolts, so you need to remove these to be able to remove the ECU from the car. Not in this case... The security cage had been binned meaning the ECU was left dangling in the engine bay. Not a good sign.
So off came the ECU which looked like this:
The black stuff is mastic. This is supposed to be used when re-sealing an ecu but I have never seen it applied on the outside of the ECU! This was a 2011 car so warranty is pretty much gone if the dealers saw this, let alone the missing security cage.
So off came the lid of the ECU and the reason for the over use of masic was clear, this ECU case is supposed to be flat so that it seals correctly, remeber that the ECU sits in an open engine bay and is likely to come in contact with heat, dirt and moisture We had to use very little effort to remove the case so this is how it was left by the previous tuner:
So once the ECU was on the bench and we had spent 30+ minutes failing to get communication with the ECU we realised there was an issue that needed further investigation, out came the test leads and we found that the boot pin had a big blob of solder left on it, not a real issue but on closer inspection the actual pad that the solder was sitting on had been overheated during soldering and the track was broken on the PCB, as you can see in this pic circled in red the pad should look the same as the 2 to the right of the circled item. The pad closest to the damage one also showed signs of overheating:
(also notice the black mastic INSIDE the ECU all over the PCB)
So we did some re-working with the soldering station and managed to get communication. Phew! With REVO software installed and some more dyno testing and datalogging, boost was back to an acceptable level, EGT's were lower, fuelling was at a nice steady 11.2 AFR under load and we gained around 20bhp over the other tune. Curves were a lot smoother, yet to hear customers 'on road' feedback but I am confident that it will be positive.
So a few pointers that you should find usefull and questions you should ask:
1. Will my security cage be re-fitted?
2. Do you cut the bolts out or remove them using other methods?
3. Will the bolts be replaced with new items?
4. Do you solder to the board?
5. Can you view the ECU before and after the work has been carried out?
These security cages can be removed without any cutting of bolts, although cutting is easier and sometimes unavoidable, great care should be taken not to damage the security cage.
Replacement shear bolts are readily available for pennies, ask that these are refitted post tuning.
NO soldering is required on most tricore ECU's and you can purchase tools to do it correctly for just a few pounds, this eliminates a lot of risk.
Remember, its your car. Don't be afraid to ask to see the work carried out, any competent tuner will be happy to show off their handy work.
