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TR7 Fuel Injection


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Right now the 7 is running reasonably... time for some modern electric gubbings. I have a Speeduino Ecu with which to run ignition and fuel injection for the 7.  I acquired an injection manifold from Ebay recently so this is now the nucleus of my hardware. I'll need to fabricate my own plenum as the OE is only suitable for LHD cars.  Sensors will be for Coolant sensor, Air Temp , Wideband Lamda , TPS, MAP as well as the obligatory Crank sensor.


I'm hoping to achieve, better emissions/efficiency and a stronger spark and if i get a HP or two extra champion!


Has anyone done this or is anyone interested in how my adventures work?  Hopefully may have it all running by RBRR.

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Yep, also interested.  Have done a few megasquirts on  6 cylinder cars and my son has Speeduino on his Spitfire.  The Speeduino was somewhat more troublesome, but I think we've got most of the bugs out of it now.

Are you going wasted spark/coilpack on the ignition?  We used a VAG coil with built in ignitors on the Spitfire, which can be triggered directly from the Speeduino ECU.


Edit: Also meant to say, you should definitely pick up some mpg and a few extra horses, but these best bit will like be the increased torque spread and driveability that brings, which is as much as result of the map-able ignition as the injection itself.

Edited by Nick Jones
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Hi Both well research is going well. 

I have the TR7 Injection head. The mating surface to the block was a bit battered so its having a skim to help it out. 

II have the ECU https://diy-efi.co.uk/product/diy-efi-core4-te36  as well . This has the option to drive 4 ignition channels and 4 injectors, so I may go for a coil on plug design, although I do have a coil with built in ignitor so may go for that first.


I have  a throttle body which i will have to mate to my own plenum I'll make.  When i have my Manifold back i'll start on that.


My 7 manifold came with 4 injectors which  I will have to clean and test. 


Fuel supply will need a more powerful pump which i will need to plumb in. 


Lots to think of , i'll try to get come picks when i get going


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20 hours ago, Nick Jones said:

Sounds like you have it well in hand. Didn’t realise there is a different head for the injection cars?


Sorry head... doh Manifold i meant. 


Nick I would be interested in shots of your Spit set up. That was my original plan but the  car got sold.

Edited by Matt306
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  • 5 months later...

Time for an update; After my failed RBRR attempt  I rebuilt the gearbox and off we went. For the last couple of months I have been running Ignition only from Speeduino, its proving stable and reliable and the engine a bit more perky. Perhaps the stronger spark and stable timing help? 


Anyway time to bite the bullet and get on with the fuel injection.

Today i stripped the manifold and water pump top.  There is a difference in the in water circulation on the set ups. On the carbs i have a take off at the rear of the head  for heater feed. From the heater the pipe return along the carbs to the water pump cover. 

On the EFI manifold there is feed for the heater at the and the pipe runs to the rear along with a differing return pipe. These are held together and clamp on to the engine where the carb fuel pump was. Of course these are unobtainable so I am making my own.

Another difference is the heater connection is on the front of the manifold as opposed to the top. There are three electrical connections, for temp guage, and EFI and a time delay heat switch , i wont be using this connection but will leave it in as a plug.


I already have fabricated a plenum, not pretty but hopefully will do the job it has a rover 200 throttle body on the bottom. My trial fit should allow me to find some securing points on the engine to support this heavy lump.




This is the differing water pump covers, 12 vane pumps the EFI is on the left.


This is the old carb thermostat the difference is clear on the below EFI one. The three electrical connections on top and heater connection on the front. The heater connection is on the bottom.






Engine stripped off.



Fuel pump cover.


This pic shows the new EFI water pump cover and a new Stainless steel pipe connecting it to the rear heater pipe.


That U Bend pipe needs to go and be connected to manifold at the front, I'll use a bit of pipe and some 90degree bends. The pipe is 3/4 inch


Here is my new EFI manifold inplace, not bolted tightly down just some nuts nipped up. The rubber runners connect the plenum. They are too long, i needed 45degree pipe hoses for this and will cut them down. The originals are no longer obtainable.



Here is my plenum popped on it needs some positioning first off!

Edited by Matt306
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16 hours ago, Nick Jones said:

or do you mean a twin progressive TB like VW used on the K-Jet Golf and Audi 80/90s?

Something like that, initial thoughts were for the Opel C20XE throttle body.
But maybe the VW item has an easier adaptable mounting  pattern.

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No updates for a day or so, there isnt much to show, but I must admit I could have photo'd more!



This is my EFI manifold when I got it it had been knocked about a bit and required some milling and building up of one of the injector port. My problem came with when i went to attach 7 UNC setscrews to the head. The eagle eyed of you will notice the top two bolt holes don't line up with the gasket, they didnt on the head. My solution was a bit basic but worked and I tested the flatness after I had done my work. I finger tightened the manifold to the head with the 5 good holes then a long scaffold pipe bent it back into shape, its an alloy metal so all should be good.



This second photo just illustrates how good it is to have proper ratchett crimpers to make the plug connectors, they are only a few quid and the neatness is brilliant.


I have the engine bay nearly sorted, the wiring is all connected, apart from the fan, which can be a sucker or a blower depending on if i plug the wires in correctly. To be honest it never comes on except when in traffic. I have a blue wire to connect to the fan relay it should all be controlled by the ECU.

The injectors are controlled by the ECU on a pair basis as i only have a crank trigger. At a later date i may try to fit a trigger wheel to the cam or redundant distributor so I can go full sequential, which the ECU allows for. They are connected by 10amp fused connection from a fuse box  for each pair (1+4 and 2+3) with the earth . The fuse box is a 6 blade trigger by a relay on the ignition, this allows the feeds for the ECU, Coil, Relays and Tacho driver. 

I have connection for Air Temp and Coolant which share a joint Earth back to the ECU. The TPS is supplied with 5v from the ECU, its a three wire TPS.

I'll do some more photos of the wiring.


One problem I am pondering is connecting the accelerator pedal to the Throttle, haven't worked that out yet.


My adapted fuel gauge sender with a return pipe added is going in tomorrow with some piping for the fuel pump and filter. Its not pretty but should work. 

I have some zip ties holding my plenum up at the moment I need to fabricate some support for underneath thats not the problem it where to attach them on the block .

Edited by Matt306
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On 14/12/2021 at 21:21, Beans said:

One of the jobs I want to do on my DHC, using an original TR7 FI system.
But with a modern ECU and distributor-less ignition and maybe a twin throttle body for more torque at lower revs.
Just need some more hours in a day at the moment!

It will be a lot easier on your car as you are RHD , I have a brake servo in the way and the steering rack. I looked at the original plenum and it looks like it would foul on my brake servo or clutch M/C

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21 hours ago, Matt306 said:

... as you are RHD ...

I presume that should read LHD 😉
Though not yet sure I will use the original plenum, adapt it or use something different.

At least I have a complete and fully functional FI system hidden somewhere.
Time will tell how that will be fitted to the DHC ...

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Well todays efforts were concentrating on completing the fuelling circuit... its all connected not pretty but connected and no leaks! I need to secure the large fuel filter cannister to the bulkhead. The fuel circuit works, the pressure regulator on the fuel rail allows for a measured 38PSI of pressure . 

My biggest problem though is the injectors seem to be dead, earlier this year they were all happily clicking away but now nothing nada nil... much annoyance.

The ECU connects up and all seems good.

I think I may just end up buying new injectors rather than faffing ... but christmas gets in the way.

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9 hours ago, Nick Jones said:

Apply 12v and tap on a hard surface. That usually unsticks them.

Back when I worked for Rover, we had some problems with the Bosch single-point injector on the Metro, sticking shut overnight. Bosch blamed the way we were driving it, claiming none of their ECUs had the problem.

Now that injector has a very specific drive requirement - initial turn on to reach a specific current, then reduce drive and hold at a lower current - which we obeyed exactly. The datasheet has clear warnings that exceeding those limits would cause damage.

So we obtained (hired!) a VW Polo with the same injector but a Bosch ECU. It turned out the Bosch ECU, on key on, switched a direct, unlimited 12V straight across the injector, in clear violation of their own specification, for about a quarter of a second. The sticking problem was clearly well known and they just brutally unstuck them every start.

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  • 2 weeks later...

So where are we now??? Well we have life! its not pretty but "SHE'S ALIVE!!!" (All cars are female aren't they?)

Above is the start, needs some tweaking and tuning i think . Loom needs tidying and wrapping. It will run along the top of the of the strut brace.


At the bottom you can see the throttle body this is from a rover 200. The accelerator cable is the TR7 one but the end cut off and shortened. I used a little cable clamp to get it in to the hole on the quadrant. The throttle body leads on to a K&N Filter . Throttle body also has a couple of inlets on the other side I'll connect the rocker breather to one of these.






No 1&2 injectors clamped into place. The pressure regulator is on the side with the fuel return rail.


Spaghetti Wiring, yes i know where its going!



More spaghetti wiring


Just a shot of the plenum and the throttle body attached. I made all this myself yes its not pretty but it works!


Part of my problems with the 7 injection manifold was the changing of the cooling pipes. Here you can see my 2 new pipe which i have welded on to a piece of steel which attached to the fuel pump cover.


Far left is a brass plug which was the original take off for water for the heater. Its plugged now and rerouted via the top pipe to the thermostat housing


More coolant pipe shots 


And again the whole shot. I must be quite proud of them as i have taken do many shots of it!

Edited by Matt306
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