Mobeck V12 standalone EFI

Your air injection system may have been removed previously, or that valve might have been used for something else, but I don’t know what. That’s the standard lovation for the thermal vacuum switch for air injection.
Are there no vacuum diagrams on the underside of the hood/bonnet, or elsewhere in the engine compartment?

My car did come with catalytic converters but no other emissions equipment. No air pump and no air injection holes on the intake manifold. I unplugged most of the vacuum lines and don’t remember where the two hoses attached to this valve went. I do not see any vacuum diagrams in the engine compartment. Either way, I thank you both for the information. I will detach the hoses and see if it affects anything. I plan to start the car tomorrow, or at least attempt to start it, so we will soon see if I removed more than I was supposed to.

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Thanks for writing up your experience with this! I’m also in the middle of installing this same kit in my XJ-S, and it sounds like we had some of the same difficulties and questions. I’m at the point of wiring, mounting the ECU, sealing off the air intake holes, and some other unrelated things like fuel lines and electric fans.

It looks like your car did have the air injection system (now removed and sealed off). You can see in this picture you posted that there are Allen-headed bolts plugging the holes for it on the intake manifold, right next to the bolts holding the manifold on:

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Nice to hear from your Troy. The manifolds that are mounted are from a 6.0 and they did come with the air injection holes. I plugged them with 7mm Allen head bolts. The ones that came with the car when I bought it had no holes. Of course, someone could have removed the air pump and plumbing as well as replaced the manifolds but that seems like a lot of expense compared to just plugging the holes, as I did. As John6 mentioned, Jaguar did some weird things, depending on the market the cars were sold in. I will be checking out your project. Did you figure out how to secure the AAV?

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I haven’t done the AAV yet, nor decided what hoses to use. What did you go with? I was a little worried by the two inlet and outlet on the AAV being different from what it attaches to on the car.

Are you in the private facebook group for owners of the kit? I posted there and got a couple ideas. Here’s a picture of Ole’s:

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I did join the group, but there is not much activity there. I will have to fabricate some kind of a bracket.

A few people might chime in if you post, but I agree, there’s not normally much activity there.

For mine I was thinking I might just zip tie it into place, but a more elegant solution would be appreciated. I’ll be curious to see what you come up with.

I will be tackling that next, together with moving the ECU inside. I will certainly post the solution I come up with.

I started the car earlier today. It ran long enough to warm up and trigger the fans. I think I have an air leak somewhere, because the RPM are not stable. I am trying to attach a video but no luck so far. Per Mobeck instructions, I checked if the ECU relay clicked when I turned the key to position 1. I circulated the fuel pump a few times and got a scare when the FPR started leaking. I checked the vacuum line and applied some vacuum to see if it is stuck. This did the trick as the leak stopped. I tried to start the car after cleaning the spill, but it wouldn’t start at first, so I hooked it up to the computer to see if the setting for the crank sensor needs to be changed. I got a message that MAXX software needs updating and after I did that, the engine started. I am very happy that I can hear the car running. Of course, there is still a lot of testing and tidying up to do.



You can’t upload a vid to J-L, post it to YT and then a link here.

Thank you Robin. I will look into it.

On one of my cars, of another brand, the idle bypass valve is held in a thick rubber “band”, which then has clips onto a metal bracket.

I’ve performed a search under the manufacturers number and drawn a blank, but I think other manufacturers may use a similar method of holding the valve.

Item no. 12 slips over the valve no.10.


A large, rubber lined, P clip would probably suffice.

On1shelf 10x 37mm Rubber Lined P Clips Hose Pipe Clamp Stainless Steel - Premium Quality- : DIY & Tools

Thank you, Dieselman. This might work to grasp the AAV itself. My bigger problem is how and what to secure it so that it is in the right position for the hoses on both ends to properly connect.

You could move the location by extending the pipes. They don’t need to be very large bore, not much air passes through them.
I note there is a blanking plate right next to the valve, you could fashion a bracket from those bolts.

I will take a look at it this weekend. Meanwhile I need to tidy up the wiring as well as find a location on the firewall for the ECU access.

I can’t be the only one on tenterhooks here…

I have been very busy dealing with the electric fan and didn’t get much further with the EFI. I should get to it this weekend. I would also like to get the videos on YouTube. Picture, or in this case video is worth a thousand words.

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Tenterhooks here too…. My Mobeck kit arrives Monday :slight_smile:


The video is now on YouTube. I just uploaded it five minutes ago and don’t know yet how to post a link. However, if you search under “1991 Daimler D6”, it should pop up. Enjoy!

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