Would you or have you used it in the past? If so what?
I thinking of giving it a try in a one in a million chance it might help my high feul trims. Engine recently suffered HGF so might be worth a go.

However I dont want any remote chance of damaging anything, if there is a chance I'd rather not bother.

 

I like gum out best for high mileage cars. Full bottle for 21 gallons first time out; third a bottle every month thereafter. I also clean the maf sensor once a month, as well as the throttle bore.

 

I've used Lucas Fuel Treatment successfully for years in fact just used it on my newly acquired XJ8 couple of days ago.

 

Just a crazy thought: Is it possible your coolant thermostat is stuck open or not fully closing? If the engine can't reach full operating temp, the ECM may be continuously enriching the fuel mixture to compensate.

Cheers,

Don

 

That's what I thought around a month ago, replaced but still same result :-(

 

Another possibility is unmetered air entering through a leak somewhere between the MAF and intake manifold, causing the ECM to enrich the fuel in response to the O2 sensor signals, or less likely, O2 sensor problems. I assume the high trims are similar for both banks?

Don

 

The one and only recommended fuel system cleaner for Jaguar is BG-44.

 

I like to use berrymans b12. Do at least double the concentration stated on the can.

My first guess on the high trims would be a vacuum leak. I have had them on all 3 of my current jags. I've noticed minor vacuum leaks (LTFT under 10 at idle) don't have much of an adverse effect.

If the trim is highest at idle, but normal at higher rpm (far less vacuum), then it is probably a vacuum leak.

The easiest way to find it is to get it smoke tested. If they find multiple leaks, just fix the worst one yourself and then see if trims are acceptable.

 

Smoke tested with no leak, also its the same high fuel trim throughout the rev range when driving, which would also suggest that it isn't a leak as you would see a drop at higher rev's. I've given up trying to find the problem, both banks both LT and ST trims maxed.


Ill give the BG44 a go then as that's easy to obtain in the UK. How much petrol should I add it to, I want a strong clean if possible.

 

BG44k is good stuff, it is powerful. When I would use it I would always add it to an empty tank at the gas station right before fill up. I would usually do a little bit stronger concentration than recommended on the can.

If that does not work, you could have a couple of the injectors flow tested to rule them out as the problem.

 

I am a mechanic with my own shop for BRITISH cars. The only cleaner that works is Techtron injector cleaner. The best thing u can do is have the engine decarbonized. A local shop should have this machine it cost around 175. But is totally worth it.

 

I second SeanB re: the choice of BG44 if looking for a fuel system cleaner. Did it on my '01, noticeable improvement. Do not overlook what others are suggesting here though. But regardless BG44 won't hurt ;-)

Cheers

 

BG44 is good. Not snake oil.

However, in my experience.....

If you are suspicious of an injector problem the best bet is to remove the injectors for professional cleaning and flow-testing by a specialist.

Next best is professional on-the-car cleaning using specialist equipment that most any decent repair shop will have. 'Motor Vac' is a name that sticks out in my memory from years ago but there are many others. As far as I know they all work on the basis of flushing the injectors with a powerful solvent. BG, among many others, had their own version of this equipment/process.

Every fuel injected car I've owned, including three Jags, has repsonded well to both of the above.

The add-to-your-gasoline fuel injectors cleaners are least effective, IMHO. Not that they're necessarily *ineffective*, mind you, but they don't work as well as the other choices.

Cheers
DD

 

The Coolant Temperature Sensor signal is one of the inputs referenced by the ECM for fuel metering. Is it possible your CTS has become lazy or out of range?

Don

 

And the third best option is to clean the injectors yourself, as I did, using mostly methods I found online, with a few twists I devised on my own. Below are links to photos of the process as I performed it.

Cheers,

Don

Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

 

Sorry for bringing back this thread but I do have a question. I put in some Lucas fuel injector cleaner and I was trying to rush because of the harsh winds we had today.

While I was trying to quickly put it in, I realized I didn't have the neck of the bottle through the filler flap. Is there a drainage tube inside the fuel filler neck that will just dump it or did it actually go in the gas tank?

I caught it before I got a whole lot and properly got it all the way in the next time.

 

You should be ok. Drains outside, just like rainwater does.

 

Speaking of rain water, Lucas fuel injector cleaner is about as effective in cleaning anything.

Don't waste your money.

 

Lucas has brought more than one vehicle's MPG up for me.

 

Oh my, an injector cleaner rabbit hole, . . . Again.

Before Ross rolls in hot telling us that it is criminal to use any of these -- I like Gumout's equivalent to Seafoam because I can't ever find BG44!

BMW, however, recommends Chevron Techron, but they probably have stock.