TR6 Fuel Injection - good mpg on a run - still Smokey on accrlerstikn

[Trever the rever]

Ive always thought my TR6 runs rich with its characteristic exhaust smell and smoke on heavy acceleration. However on my many long runs including to Le Mans I do honestly get good mpg of 30-32. Recently on a spring trip to Devon with the Essex TR group I experienced the same mpg filling up at 225 miles with an indicated 1/4 tank left. I know many TR6 owners wouldn’t dream of letting the tank to such a low level. My Bosch type pump is 15 years old and during one scary experience in France it was still running prior to refilling with 38.5 litres! ( I have witnesses!). 
Anyway back to my point, under low throttle openings at speed (60-70) the mpg is clearly good but on acceleration the smoke is there and exhaust smell noticeable in the back draught leaving our clothes and hair in need of a clean. I’m happy with engine timing, butterfly set up etc. 
I’m concluding I need to renew the metering unit as it is 15 years old and 40-50k miles. I’d welcome any thoughts on my experience. I am driving to Malvern from Essex this Friday, so expecting the same issue. 
Regards Trevor Hughes 

[stuart]

10 minutes ago, Trever the rever said:

Ive always thought my TR6 runs rich with its characteristic exhaust smell and smoke on heavy acceleration. However on my many long runs including to Le Mans I do honestly get good mpg of 30-32. Recently on a spring trip to Devon with the Essex TR group I experienced the same mpg filling up at 225 miles with an indicated 1/4 tank left. I know many TR6 owners wouldn’t dream of letting the tank to such a low level. My Bosch type pump is 15 years old and during one scary experience in France it was still running prior to refilling with 38.5 litres! ( I have witnesses!). 
Anyway back to my point, under low throttle openings at speed (60-70) the mpg is clearly good but on acceleration the smoke is there and exhaust smell noticeable in the back draught leaving our clothes and hair in need of a clean. I’m happy with engine timing, butterfly set up etc. 
I’m concluding I need to renew the metering unit as it is 15 years old and 40-50k miles. I’d welcome any thoughts on my experience. I am driving to Malvern from Essex this Friday, so expecting the same issue. 
Regards Trevor Hughes 

When was the last time you had your Dizzy rebuilt?

Stuart.

[Mike C]

I had exactly the same problem and accepted the smelly clothing,post drive showers   etc as part of the Triumph experience. Tried fixing the boot seals etc but no improvement. Then I had my MU and injectors rebuilt and recalibrated due to damage from the newer generation of Australian fuels- and the petrol smell disappeared . And the car's performance improved so much it felt like a different vehicle.

Looking at the before and after calibration curves my MU was overfuelling by maybe 20% over much of the operating range. I'd suggest getting the MU and injectors rebuilt and recalibrated as a set.

[Trever the rever]

Ref the distributor, hands up, never, apart from new springs (the same) a few years back. I have the contactless Lumenition electronic ignition which I had to replace after it failed with an equivalent last year from a company in Basildon. The MU is at least 15 years old though I sent it off to (I can’t remember who without going through my files) have it recalibrated about 10 years ago. Twin sports exhaust and 6 branch (2 x 3) fitted about 15 years ago too.  Nothing much done since. I do get popping in the exhaust on the overrun after the exhaust was fitted. 

Thanks for the feedback! 

 

[barkerwilliams]

I had similar smells of fuel and spent some time tracking, sealing renewing to no noticeable result.

Then bought a couple of metres of elastic and stretched around the boot lid and tied a foot of wool evevy six inches to the elestic across the boot lid and went for a drive. Once the car reached about thirty mph the centre telltales of wool reversed direction and were blown forwards towards the cockpit as the square rear of the car created a backdraught. My twin sports exhausts passed the exhaust gases directly into this forward moving airstream. Cost less than a fiver to test.

A went to Phoenix Exhausts and bought a mid & rear section of exhaust in which the exhaust is in the original NS position and the fumes no longer enter the car. 

Alan

[John McCormack]

On 8/9/2021 at 11:08 PM, Mike C said:

I had exactly the same problem and accepted the smelly clothing,post drive showers   etc as part of the Triumph experience. Tried fixing the boot seals etc but no improvement. Then I had my MU and injectors rebuilt and recalibrated due to damage from the newer generation of Australian fuels- and the petrol smell disappeared . And the car's performance improved so much it felt like a different vehicle.

Looking at the before and after calibration curves my MU was overfuelling by maybe 20% over much of the operating range. I'd suggest getting the MU and injectors rebuilt and recalibrated as a set.

Hi Mike, my car runs rich, I get 25mpg or thereabouts on a trip. Around Sydney I get much worse but then I live in the inner west so am effectively in the city traffic wise.

A couple of questions if you could thanks.

Who rebuilt your MU and injectors? Is there any issue with removing and fitting the MU, can it be cocked up.

[Mike C]

I used Peter Bower from Bower Power Auto Tech.

https://bowerpower.com.au/

You'll need to talk to him because his source for TR6 viton MU seals dried up and he only advertises Maserati under his Lucas services. If you can supply the viton seals he might still look at TR6 MU's. He has the original Lucas Australia service equipment which helps- the calibration charts he gave me for my equipment were in the same format as the Lucas handbooks.

To remove the equipment I labelled the cylinder number on each injector and its serial number , timed and removed the MU as per the brown book and  shut off the petrol supply line valve I've fitted. A small crescent ring spanner helped in removing and reinstalling the MU.

If you post the equipment , like I had to, you'll need to drain the petrol from it and wrap it in old towels before putting it in a sealed express post bag.

If you have any problems Peter is very helpful over the phone.

 

[John McCormack]

3 hours ago, Mike C said:

I used Peter Bower from Bower Power Auto Tech.

https://bowerpower.com.au/

You'll need to talk to him because his source for TR6 viton MU seals dried up and he only advertises Maserati under his Lucas services. If you can supply the viton seals he might still look at TR6 MU's. He has the original Lucas Australia service equipment which helps- the calibration charts he gave me for my equipment were in the same format as the Lucas handbooks.

To remove the equipment I labelled the cylinder number on each injector and its serial number , timed and removed the MU as per the brown book and  shut off the petrol supply line valve I've fitted. A small crescent ring spanner helped in removing and reinstalling the MU.

If you post the equipment , like I had to, you'll need to drain the petrol from it and wrap it in old towels before putting it in a sealed express post bag.

If you have any problems Peter is very helpful over the phone.

 

Thanks Mike, I've met Peter. I can deliver the car to him if he still does the complete job.

[JohnC]

5 hours ago, John McCormack said:

Who rebuilt your MU and injectors? Is there any issue with removing and fitting the MU, can it be cocked up.

FWIW, Peter Bower and his late father in law (Justin) recalibrated my MU many years ago, and it ran flawlessly after that. Justin also refurbished the throttle bodies, which was an important factor. Peter is indeed very helpful over the phone, to the extent that I feel a bit guilty whenever I call him! I know Peter has been reluctant to touch TRs recently. Twenty years later, I have now replaced all the 'O' rings & seals again, and all is good.

Removing and replacing the MU is very straightforward. So is replacing all the Viton seals, providing you are scrupulously clean. David Clark stocks them all. I'd suggest replacing all except the two diaphragms (they are v pricey). While you have the unit apart, take careful photos of the MU diaphragm, as there is more than one type. AFAIK, there's only one type of CU (vacuum) diaphragm. Get yourself a copy of the Lucas PI handbook (plenty available online, or PM me if necessary) as that details the steps. It also describes how to check the non-return valves at the MU end of each injector line. If any of those need replacing, I'm not sure who can help locally. David Clark possibly, and Peter almost certainly.

As long as you don't mess with the datum track, max fuel, or control rings, your MU will remain calibrated. If you're still not happy with how the car runs, then is the time to send the unit off to Peter.

Hope this helps. Feel free to call - you have my number.

Cheers,
John

[John McCormack]

2 minutes ago, JohnC said:

FWIW, Peter Bower and his late father in law (Justin) recalibrated my MU many years ago, and it ran flawlessly after that. Justin also refurbished the throttle bodies, which was an important factor. Peter is indeed very helpful over the phone, to the extent that I feel a bit guilty whenever I call him! I know Peter has been reluctant to touch TRs recently. Twenty years later, I have now replaced all the 'O' rings & seals again, and all is good.

Removing and replacing the MU is very straightforward. So is replacing all the Viton seals, providing you are scrupulously clean. David Clark stocks them all. I'd suggest replacing all except the two diaphragms (they are v pricey). While you have the unit apart, take careful photos of the MU diaphragm, as there is more than one type. AFAIK, there's only one type of CU (vacuum) diaphragm. Get yourself a copy of the Lucas PI handbook (plenty available online, or PM me if necessary) as that details the steps. It also describes how to check the non-return valves at the MU end of each injector line. If any of those need replacing, I'm not sure who can help locally. David Clark possibly, and Peter almost certainly.

As long as you don't mess with the datum track, max fuel, or control rings, your MU will remain calibrated. If you're still not happy with how the car runs, then is the time to send the unit off to Peter.

Hope this helps. Feel free to call - you have my number.

Cheers,
John

Thanks John. In fact the car runs superbly, David Clark reckons it is great as it is. It is just the fuel economy that is a bit higher than others say they get.

David has said don't touch it, it is working fine. The entire system was rebuilt by Peter Bower a few thousand miles ago but quite a few years back.

[JohnC]

Aah. Got it.

TBH tweaking the fuelling for better economy is a painstaking task if anything is non-standard. I gather Peter has fuelling curves for the standard cars and a couple of aftermarket cams. If your setup isn't one he has on file that's much more of a challenge, and I suspect quite costly in terms of time (and so $). I've gone the DIY route - I have a wideband AFR sensor with log which also records RPM and manifold vacuum, and a homemade vacuum generator for the calibration. I use the log in lieu of a rolling road, and then model the changes I want on my laptop before adjusting the calibration on the workbench. Great fun

Cheers,
John

[Trever the rever]

I have a number of jobs to do but a refurbed metering unit will be a step in the near future. I've also decided to get shot of the twin sports exhaust to eliminate the efflux issue once and for all. However ideally I'd like to keep the 2 x 3-1 branch manifolds (TT1230S1) that were fitted with this exhaust, mainly to save on cash. I think they were part of a 'falcon' system sourced by moss about 15 years ago.

Could anyone specify what standard or similar exhaust that could be fitted to these manifolds ? or would I have to have an adapter made up to fit a new exhaust? Welcome your thoughts.