Terraclean service on V12 HE

[davidr]

I decided to try this service on my V12 Coupe as I was unhappy about the way it was running and felt I had an uneven idle quality, especially when compared to my 6 cylinder Celebration. Maybe I'm being fussy but it doesn't quite feel right.
I've already been right through the ignition system and changed the distributor rotor and head and the plugs and leads. I've also synchronised the throttles, all of which brought improvements but still not good enough for me!
I booked into Columbus Autos near Devizes as they are near my office so I could nip out at lunch time.
The process works something like this. There are 2 cleaning fluids that are pumped neat into the fuel rail and the engine runs on them whilst the cleaning is taking place. The first fluid cleans the injectors and the backs of the inlet valves ( if the car doesn't have direct injection) and the second fluid cleans the combustion chamber, outlet valves and beyond.
The fluids I believe are a very highly refined fuel that is ionised to attract carbon particles.
The way we went about it was as follows.
First we left the car ticking over and analysed the exhaust gasses. The CO was 0.5% and the HC's were around 85ppm. This was consistent on both banks.
The technician remarked that these were good readings. In fact they would pass the test for a car with catalytic converters so not bad for one that doesn't have them!! To put it into context, the MOT limits I think are 2% CO and 400ppm HC's so well within.
Next step was to depressurise the fuel system by pulling the fuel pump relay and running the car until it stopped. We then disconnected the fuel filter and plugged the machine into the pipes. We also clamped off the fuel return line from the fuel rail.
The machine uses an airline and its own adjustable regulator to pressurise the fuel rail to the required 2.5 bar. The machine is then charged with the 2 fluids. For this car a large and a small can of each was used. For smaller engines then less would be needed.
Next step is to start the car and run it on the cleaning fluid until the machine beeps that the fluid has all been used. The injector fluid goes in first and then the combustion cleaner. The process should take a while as the car ticks over and uses up the fluid. We put this kettle on to wait!
However, it doesn't take long on a V12!! "Bloody hell this thing drinks!!" said my man. To be fair, he did put another bottle of cleaner through it at no extra charge.
Next we disconnected the machine and put the car back together to run it on its own fuel then analysed the gasses again.
Interesting!! The CO had gone down to 0.25% which was half the initial value so very good. But the HC's had gone up to about 185ppm. Still well within MOT limits but not good!!
So a bit of head-scratching later we came to the following conclusion.
I had my suspicions of the fuel pressure regulator before we started thinking this was a possible cause of the lumpy idle. So my theory was that, if it wasn't reducing the pressure in the fuel rail as it should at idle then the newly cleaned injectors would be chucking more fuel in than they were before and hence the higher HC's?
So I ordered a new fuel pressure regulator.
Impressions on the way home were that the car was running better, appeared to be quieter and pulled better. Idle was not any better though. A bit early to give a final verdict I think.
the guy at Columbus Autos was very helpful and impressed me in as much as he had never done this to a V12 Jag before and I'm not sure he'd ever worked on one. However, he did his research on his computer, asked loads of questions and didn't rush into it. He even spotted the "do not slam" sticker on the bonnet and asked me how to shut it and stood back to watch as I did. He was obviously interested in learning.
The cost? It was £150 which was for a large and a small bottle of cleaner. For engines up to 4 litres it only needs one bottle and that's £110. I think I was fairly treated considering that he used an extra bottle!

[davidr]

I thought I'd pop out and fit the fuel pressure regulator. Easy job I thought. The car had other ideas!!
As we all know, the trouble with old cars with very high under-bonnet temperatures is that the rubber pipes cook and go brittle. So guess what?
Yes - the pipe on the back of the regulator disintegrated when I pulled it off with difficulty
Well no worries thought I - I'll just go into Jaguar Classic Parts and order another one and maybe replace the others while I'm in there. Then up came the dreaded "no longer available"
So I guess I'm going to have to have it repaired by someone like Pirtek unless anyone has any other ideas?

[Brakebuster]

David

interesting read,

first of all, the fuel pressure regulator, i take it your talking about the regulator on the left hand bank that goes back the the fuel cooler ? as this is the only one with a ' rubber ' pipe directly onto the back of it, the other regulator has a union fitting on both sides , if it is only the rubber and jubilee clip fitting, then get some fuel rated pipe and a straight connector to join the pipes back up at a good point ? or run directly to the fuel cooler as that is a jubilee clip as well , i think i have some i could bring to the next Kemble ?
also , if your changing one regulator, then it would be wise to change the other, as the diaphragm probably isn't in the best condition after 25 years as well.

onto the engine cleaning,

hmm , not decided myself, though £150 isn't cheap , its not bad if the results reflect lower emissions and better running, but has it ? no doubt there is some internal cleaning , and it would give the injectors a proper clean without the need for removal and new pintel caps etc ( which i have done )
but wouldn't regular use of an additive reach the same results given time ?

will be interested to see if everything settles and the engine gets ' smoother '

BB

[davidr]

BB - thanks for the offer of some fuel pipe. I do have some and that's what I did to get the car going again. However, I would like to fix the original pipe because I don't like to leave these "get you home" fixes on the car if I can help it.
Yes it was the output regulator that I changed. I thought it worth a first try as its half the price of the input regulator!
I've yet to take the car for a decent drive so I'll report back when I have.
Regards
David

[davidr]

I've now had a chance to drive the car for a longer run and I'm now sure that the Terraclean has made an improvement. The car runs cleaner and quieter and picks up much more briskly so it has had a noticeable effect. Was it worth £150? Well if you took your car for a "tune up" that cost that much and it felt much better on the drive home then maybe you'd be happy. £150 is about 1 hour labour at a main dealer, 2 hours at an independent specialist? I feel I've had a good benefit from it but I'll leave it to others to decide if it's worth the money!

What I haven't improved is my lumpy tickover so I have ordered an fuel pressure regulator for the input side as well. As I said in a previous post, I changed the output regulator and didn't feel that this made a difference. However, it definitely needed changing as it would make no difference to the tickover if I pulled the vacuum hose of the old one but it does with the new one. (and no its not just the engine pulling more air through the vacuum hose as I had my finger over it!) When I pull the vacuum hose off the old input regulator it makes no difference so I think its worth trying a new one.

As for the outlet fuel hose, I couldn't find a hose repair company willing to tackle it so decided to have a go myself. In the end it was simplicity itself. The line is an assembly of a metal pipe that goes beneath the inlet manifold with rubber hose swaged onto each end that fits onto the outlet pressure regulator at one end and the fuel cooler at the other end with push-on fittings and hose clamps. Cutting away the swages and taking the hoses off reveals a reasonably long length of barbed pipe connector. This is easily long enough to push 5/16ths pipe onto and secure with hose clamps. Note that these were proper fuel hose clamps and not jubilee clips. The only other recommendation I'd make is to put the metal line in first and then put the hoses on. If you try to do the whole thing in one go then it's much harder to get it between the inlet manifold and the cam cover because the clips get stuck. That may even be the reason that Jaguar went for a swaged connection in the first place as they were obviously happy with a push fit and clamp as they used that at the other end so I don't feel that my fix is unsuitable.

Will post again when the input pressure regulator has been fitted

PS apologies for lack of pictures. I'd done it all before I remembered to take some photos and didn't have time to take it apart again!

[Brakebuster]

great info



BB