Mobeck V12 standalone EFI

Thomas IvanGrozny’s link:


Wohoo! It just started right up?

This past weekend I was working on relocating the ECU to the passenger side of the cabin. I first had to find a grommet that would accomodate a rather large ECU plug. I found one on a Honda at the local junkyard.

Initially I thought that the best spot would be next to the existing wiring to the left of the ABS.

However, when I removed the glovebox, I discovered that the blower is located in that same location so I had to rethink my initial plan.

The only spot big enough turned out to be on the other side of the blower, behind the rubber hose. So I measured the grommet, made a template and started drilling. There is not much maneuvering space from either side, which makes progress slow. I used a drill for initial holes and will then use a Dremmel to connect and refine the edges.

1 Like

I next need to find a suitable spot to secure the ECU and enable me to access the plug in the back in case I need to adjust the settings. I hope to do that in the next few days. I also need to install longer lug nuts, which should be arriving soon. After that the car will be insured, registered and driven to test all of the systems, especially newly installed EFI and electric fan.
Meanwhile, I started looking at the manual transmission conversion. I hope that some of you are still following this and can chime in with your opinions whether I should start a new thread on that topic. I know that it was discussed before but it seems that not much other then discussion happened at the end. I am not interested in just discussing the topic but am really intent on doing the conversion. I already looked at several kits and contacted vendors. I am particularly interested in the Tremec TKX. So far, I can’t find anyone who has completed the conversion using any of the kits available and posted it anywhere.

1 Like

The ECU was placed in the rear to avoid engine heat and vibration to impinge on operation, Thomas. Modern ECUs may be more resistant, and cabin placing is fair enough - OEM’s size would certainly limit convenient placing…

xj6 85 Sov Europe (UK/NZ)

I think you have enough space under the blower, it looks like the ECU is quite small.
May you will have to move the Cruise Control module that normally resides there, but that’s easy.

I already removed the cruise control module. I have no need for it since I also removed the bellow. I also thought about putting the ECU in that location but I am not sure that there is enough space there. The module is about half the thickness of the ECU. I would have to make another bracket since the one for the module is too small.

I finished moving the ECU into the cabin. I still don’t know where to mount it. There is not enough space to put it where the cruise control module was or horizontally under the blower( there is flap on the bottom of the blower housing that opens outward in the same location). It will probably end up going to the right side kick panel of the footwell. I don’t really like it there and will still look into other options.

Mobeck enclosure for the ECU has the computer access socket covered, for some reason. To allow me to plug in the computer cord, I used a Dremel to remove some of the material.

I probably missed this, but why are you intent on moving the ECU into the cabin? Surely it is intended to be in the engine bay?

Every car that I know of, that has an ECU, has it away from the engine bay. Every Mercedes, BMW, Opel, Mazda, Honda,etc. that I have owned had it somewhere in the cabin. Even the factory Jaguar ECU is in the trunk and not near engine heat, grease/oil, moisture or accessible to critters. The supplied enclosure for the Maxx ECU is not very sturdy and the connections/relays are somewhat exposed. After spending almost 6K Euros and countless hours on this conversion, I want to make sure it is as secure and protected as possible. I know that Mobeck provides a bracket to mount it next to the brake booster, but, in addition to the already mentioned reasons, I plan to switch to a manual transmission and this location might interfere with clutch master mounting and plumbing needed for that conversion.
I know that most people are not comfortable with making holes in the firewall, so for them using the supplied bracket and location might make the decision to purchase the kit more acceptable. I think that this could be one of the reasons Mobeck decided to mount it there.
Another reason, although not that important, is the ability to sit in the cabin, have the computer hooked up to the ECU and play with the settings while looking at dials and not exposed to cold, rain or whatever else is going on outside.

1 Like

Are you talking about the kick panel of the center console or the other side, in front of the door?
The later could be a very good option if it fits, and easily accessible.

My Motec has been in the engine bay for 13 years and no issues as yet - however if you want to mount it in the cabin - fix it to the floor under one of the front seats.

1 Like

Next to the passenger’s right foot and the door.

I think that Australian climate is much easier on the wiring and electronics. Here, it rains all the time, and we also get snow and salt in the winter. My car is not going to be garaged, which is another factor to consider. It is not something I suggest everyone needs to do but It took me only about three hours and a few Euros to finish. Another plus for “hiding” the ECU is for those who want the engine bay to look more stock, in locations were an inspection is required and anything looking aftermarket needs approval. When I am done, I doubt that anyone not familiar with Jaguar V12s will be able to tell that modifications were done in the engine compartment. I even salvaged the yellow warning sticker from the old fan shroud and applied it to the new one in order for things to look stock. Of course, this photo was taken before I cleaned and wrapped all of the wiring.


Mazda VW Mercedes… they all make cars with the ECU in the engine bay.

1 Like

That is why I specified, “that I have owned”. I do what I feel comfortable with and what I think will get me the most for my investment. For me, 6K is a lot of money and my time is even more precious. I plan to keep this car for a while, and I don’t think it would be smart to have to do this again in a few years. My 450SL has its D-jetronic analogue ECU under the passenger side dash. It has been there for almost 50 years and still working fine. It seems like a good, safe location for ECU.

The cabin is not a bad place, I was just noting that reliable cars had ECUs in their engine bays for decades. Some 90’s BMW for example in the fuse box on the side the brake booster isn’t. Mercedes right on the engine next to the Kompressor or on top of the intake of V engines. Mazda next to the engine. If it’s not out in the rain it seems to last.

As to the boot mounted ECU they either ran out of space or were worried about interference from the ignition…

Which again raises the question ‘is the game worth the candle’, Thomas…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

I don’t know. I hope so, but I haven’t gotten the car on the road yet to see how much difference it made. It would certainly be more financially responsible to drive a Toyota Corolla. However, this is a hobby car and the criteria are different. I wanted better performance and fuel economy promised by the kit as well as to prevent expense and issues that are going to come up eventually due to the age of the factory EFI, ignition and idle control. Those are well known problems of these cars and the expense would probably end up being the same, although over a longer period of time.
As I mentioned earlier, a few hours and Euros I spent on relocating the ECU inside, compared to the cost of rest of the project, seems quite reasonable in order to protect the most expensive and sensitive part of the kit.