Mk4 ecu problems

[Bish]

So I have a misfire on my mk4 03 gti 160000kms. I scanned it and a coolant temp sensor came up as well as throttle valve so I did the coolant sensor which didn't fix it. So next I replaced the plugs, that didn't fix it. So went to the next, did the coil pack on cylinder 1 and that didn't fix it either. My ignition amp is fine I checked it with a multimeter and the wiring to the coil packs is also sweet as per multimeter readings. Thought I'd get it scanned with a mechanic I know and this time injector 1 and 2 came up. First thing I did was check the electrical pulse to the injectors and it was all good so I did the cheap option and used Liqui Molly injector cleaner for a couple of tanks and that didn't fix the issue. When I was overseas someone kind enough to my car to their mechanic and he did a run through on the same checks as I did also checking and cleaning my injectors. The mis still didn't get fixed. He had suspicions that it was a computer fault and so sent it off to someone else to check out the computer. Iv been back from overseas for 2 weeks now and they still can't fix it. Next resort is to change the ECU. Now Iv got a couple of options.

1) go genuine which will set me back big $$$
2) go used/upgraded to a stage 1

I'm leaning to going used but I don't know what I'll have to do to get a used one to work properly on my car.

What are your suggestions? Anyone have similar issues? Any other suggestions?

[h100vw]

06A906018CH is going to be the part number.

You can swap the immo chips between old and new ECU and that should work

[Bish]

Ok sweet. What are the advantages of buying a new one as opposed to used

[h100vw]

I wonder if you can actually get a new one. Your wallet will appreciate the secondhand one more.

[Bish]

Does that mean I can go and rip one out the same car at the wreckers?

[Umai Naa!!]

New one will be an exchange refurbished unit.

I think by 'new' he means new to the vehicle, not brand new.

[h100vw]

the immobiliser wont work on anything that you just fit to the car.

You could get one from a wrecker though. It would start for a second and then cut out.

[Lynchy]

Just from my research and for my 2c, If you managed to pull the ecu, instrument cluster, barrel and key from a wrecked car, you could do the swap without needed to defeat the immobiliser.

[beale187]

Just from my research and for my 2c, If you managed to pull the ecu, instrument cluster, barrel and key from a wrecked car, you could do the swap without needed to defeat the immobiliser.

Ooh good question. I know where your going with this Lynch. In your case (and mine shortly) im thinking the BCM (body control module) would be different? Maybe someone more enlightened can answer this...

[Umai Naa!!]

BCM is for the central locking. You could probably just swap the button portion of the keys over.

[007]

Are you sure it's the ECU? A misfire can also be caused by a leaky hose or stuck check valve. Just my 2c worth but it might be worth checking for leaks before you go to the trouble of changing out the ECU.

[Bish]

The latest on it is that the ecu is fine. It's going back to the shop to be checked for dodgy wiring between the computer and coil 1. There's no spark when you unplug it while the car is running as opposed to the other coil packs

[h100vw]

ignition control module on the airbox.