free hit
Dropping the ECM and all of the factory wiring. - ECU/Freescan/Espritmon - The Lotus Forums Jump to content
Sign in to follow this  
Roberto Esprit

Dropping the ECM and all of the factory wiring.

Recommended Posts

Where to start. Sorry no photos yet. So I went to start the car one day after swapping in a geraric 02 sensor. I thought I was going to eat my own words of it working because the car idled horribly again and I was back to throwing multiple codes. I did some digging and found no bolts in the manifold... That would cause a rich condition for sure. Well I couldnt get the bolts in as I had no fast source for studs and I noticed a big oil slick on the frame and all over the motor. So I started to pull the engine. Everything stated out ok. Wires unclipped nothing too bad but some corrosion that might explain the jumpy gauges at times. Then I got to the passenger side firewall. I forgot why I wanted to pull it but I wanted to. I dont know if lotus does this or this is some idiots idea of a joke but the wires had no clip. They were taped up to the ECM. That was the last straw.

Carefully but quicky I pulled the following:

Cat probe wire: Blue

All ECM cables



Crank sensor

Idle stepper

Oil pressure sensor

and slightly unrelated I am removing the vac pump and the charge cooler pump.


This will be replaced by:

Mil spec short harnesses with TPFE coated nickle plated wire that is loomed and heat shrank.  This will be modular seperating into Main. Ignition, Injection, Sensors and a seprate single bundle for the stepper controlling idle. Boost will also be on its own short loom. This should greatly reduce tear down time.

The ECM will be a Haltech Elite 1000. Which can shut down the engine based on preset limits.

Vacuum and CC pumps will be electronic. I already have a Hella vac pump for the brakes for now. This may change to no vac pump and all steppers for the aircon as I have all of that as well.

This is not a happy mod without a point but rather a necessary evil as I do not want the freshly rebuilt engine to fail due to a bad ground.


Speaking of grounds I am working out A new system for the electrical. Since I am not going to place the battery back in the OEM location and nor am I re using the wires that came with the unit I am at a loss of where to put the Battery. It will be lithium in a bit smaller capacity but I still do not know where I should put the unit. 4 locations come up as prime restate. Behind the passenger seat, Over the passenger fuel tank and up in the front of the car.  This all has to be factored in with the fact that I am running a ton of non factory electronics including but not limited to door speaker's a DSP ignition coils that do not need an igniter and a huge altenator that may go where the vac pump once lived. 

I want to Keep my cable runs short but I also need enough power to run a small amp and the new electronics. I hope that by using Led bulbs and modern injection and thicker wire that the overall system load is reduced.


That is all for now. If anyone has relocated the battery and is happy with their choice pleas tell me where you put it. 



  • Like 1

Share this post

Link to post
Share on other sites
Upgrade today to remove Google ads and support TLF.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

  • Create New...