Help with ECU swap on Elise S1

[seb486]

Hi there,

Hello from France ! (and please apologize in advance for some incorrect spellings in this post)

I am new here and seeking for help... I have an Elise S1, Rover K engine 120hp (non VVC) 2001 and I want to swap the factory fitted ECU with an second hand one.

Here is the painting :
My S1 has the factory fitted Cobra volumetric alarm and immobiliser + 5AS module. My factory ECU model is Rover MKC104112. I have the immobiliser bypass from https://www.eliseparts.com/shop/engine-br-gearbox/... fitted on the car.
Immobiliser bypass works well (I mean I do not need to mobilize the engine with the button prior to start the engine : I just turn the key and the engine starts).

Now I want to swap the original ECU with a second hand one (Rover MKC104111 I found and I read it was "compatible" with my original MKC104112).

I have plugged the engine harness and the MAP sensor vacuum tube into the aftermarket ECU and tried to start the engine. The engine started for a couple of seconds then stopped... tried again... same thing. Always same again...

I suspect that the second hand ECU cuts the fuel pump because it has to match the factory fitted 5AS module (despite the immobiliser bypass still plugged).

Am I right ?? Can someone tell me how to get out that and have my engine start ? Can the aftermarket ECU be somewhat unlocked ?

I am stuck with that. Any help greatly appreciated !

Thank you.

[_Bandit_]

You may get a better response on Seloc.org so worth posting this question on there

[seb486]

Thank you ! Will try a post there.

[dnb]

You can indeed get a Rover MEMS ECU unlocked. I did this when my S1 ECU coil driver died and it was cheaper to put in a 2nd hand ECU than mess about repairing an old one.

You need an EEPROM programmer, a 8 pin DIL socket clamp and a small data file to program into the immobiliser EEPROM chip.
The worst bit of the job is to get into the ECU casing.

[gareth h]

I had my Caterham k series ecu remapped and de-immobilised by https://www.kmaps.co.uk/services, Mark was involved in developing the unit originally for Rover, might be worth dropping him an e mail.

[seb486]

Thank you guys for your answers. EEPROM programming is a bit too tricky to me !

Any PC home software you know that would do the job through the diag socket?

[the av8er]

The Elise has a complete loom install from a MGTF. Including the parts not needed for the lotus. This includes the small box that usually runs the MG alarm / immobilizer with light flasher, central locking etc. and is now left dormant.
This box is coded to the ECU, known as mems matched. Either change them as a pair or have the ECU recoded to match.
You'll find this small unit if you remove the dash binicle, it's mounted behind bolted to the dash.
Hope that helps.

[seb486]

It is !
Thank you.

[the av8er]

How did you get on ??