Abnormally high fuel consumption, related to Electronic Parking Brake (EPB)?
 

Hi everyone!

I'm new to this forum, and just introduced myself on the dedicated section.

I'm from France and bought a beautiful S-Type 2.7D Excellence 5 days ago, and I'm so happy with it!
It have 140.000km (87.000 miles).
But, I think there is something strange with my fuel consumption...

I average 12,5 to 14 L/100km (17 to 19 US mpg, or 22.5 to 20 uk mpg) in the city, trying to be as gentle as I can with the throttle pedal... and I have something like 8.5l/100km (28 US mpg or 33 UK mpg) on classic roads (not highways).

These measures seem to be very high to me, reading what other members fuel consumption is with the same 2.7 diesel motor (something like 30% lower!).
I know this engine can be thirsty when it's cold outside (but it's not cold these days) and just when the engine is cold, but this consumption remains the same after 15/20 minutes.

The car have a brand new timing belt, new tires, new electronic parking break motor, filters, and is running perfectly, with no strange noises.

I noticed that the gearbox stays in 4th gear when in town at 50kmh (30mph), at about 1500rpm, and at a stabilized pace at this speed on a flat road, I have about 7L/100km (33,6 US mpg, 40 UK mpg) which seems to be a lot too.

I was thinking about a problem with sticky brakes, or electronic parking break. So I disabled EPB, elevated each wheel one by one, and make it turn by hand.
The two on the front were totally free, stopping after at least 10 seconds. But the two rear wheels stopped about 1 second after.
Do you think it's normal? Isn't is supposed to be like the front wheels, totally free?
This could explain a light fuel over consumption, but, I don't know...

Please, what are your thoughts about it?

Thanks a lot, have a great Sunday!

Guillaume

It's RWD (rear wheel drive) so the rears will never be as free as the fronts.

Ok thanks, I thought it had no real impact when the gearbox is disengaged, and this « lack of freedom » was due to the electronic parking break which is (maybe I’m wrong) also on the rear brakes.

I’m looking for ideas that could « mechanically » cause this over consumption problem.

Is it possible maybe to temporarily unmount the EPB in order to eliminate a EPB problem?

Guillaume

It doesn't sound like the EPB - and you could do with help from other 2.7D owners because maybe you don't have a problem at all.

unplug the module or take out the fuse. You will get a warning light and maybe cruise disabled.
Jagv8 has a good suggestion about fellow diesel owners experience. The one thing i know for sure is the more the throttle is given the more the turbo gives boost and thus more fuel burned. Wish that car could come to the states. I would love to have a second s type in diesel. Diesel is my background. 30 years around them from 2 cylinder pony motors to 1000 hp and up heavy duty

Your fuel consumption does seem high when out of town. You should be in the low to mid 40's miles per UK gallon. You don't say what year it is so I don't know if it has an exhaust filter (DPF).
When I bought mine, I had the same issue with bad fuel economy & less performance than it should have (this you may not realise if you've not driven one before). It's worth getting it checked to see if the EGR valves are functioning correctly.

Edit:- those engines do take quite some time to warm up fully.

Thank you!

It is a 2008 model, one of the last units, so it should have a DPF!
For performances, it's quite difficult to know as you said, but it seems to me that is pretty rapid...

For the EGR valves, isn't is supposed to be an alert message when it is clogged?

Guillaume

Not just clogged, sometimes the valves don't operate (open/close) correctly. I replaced both of mine & had no lights or warnings but did have some codes. As you have a DPF, maybe worth checking how full it is (they don't last forever) as this can affect the MPG too. Worth getting a full scan on Jaguar SDD/IDS ?

Another thing that I always remember: you don't know how the previous owner drove it. I've had more than one car that didn't seem very 'willing'. Maybe spend some time in Sports, giving it a bit of stick & clear it out ?

Just some suggestions if it's not the brakes - & that's a big enough difference in fuel consumption to notice quickly if any brakes are binding.

Good luck !

Hello Guillaume,

Lovely choice of Jaguar, and welcome to the S-Type forum.
I will not comment too much on city driving because, thankfully, I do so little in my 2007 2.7L TTD, but those city numbers may, as JagV8 says, point to fairly normal for today's stop and go conditions in big cities. As for your flat, non urban driving, say pushing more towards 1900rpm, a figure up to 7L/100Km sounds about right. I have squeezed mine out to 5.1L/100Km (55 imperial mpg) over a full hour of motorway driving, but at a boring 100Kph that leaves much of this car's touring performance well hidden. Any current buzz-box can do that.

A few comments are warranted to the new owner/driver of the TTD . . .

• check out the Diesel specific forum as well as this S-Type forum (and perhaps the UK forums where there were greater sales of the TTD);
• pay strict attention to the Stickys and other threads on dipstick monitoring, DPF regen (your car will definitely have DPF), and coolant fitting failure;
• note also the S-Type specific threads on EPB recalibration and battery induced false issues (issues where you start throwing money at shadows - see my sig).

None of the foregoing detract from this fine car, but to my mind and based on many years maintaining and loving her, this is an engine/auto/car combination far more comfortable on higher speed country touring rather than mixing with the stop/go rabble in cities. BTW, both our cars enjoy the ZF6HP26 6-speed auto, which is silky smooth. So, 4th gear in town? No issue there. A final note . . . not doubting for a second that, with Jaguar telling us that the 2007/2008 crossover was at VIN ending N80181, and accepting that my car is a 2007 and yours a 2008 . . . reality also tells us that the production line formerly used by these last S-Types was fully tooled and producing XFs from resumption in the 2008 new year. The new XF was widely available at dealers from March 2008. So, with production and stockpiling as prevalent then as now, there is no doubt that all 2008 S-Types were actually built in 2007.

What to do? I agree with JagV8 . . . be very cautious you have no problem at all. :icon_lolsign:
If the EPB concerns you, do the recal. Good advice also that the gearbox adaptations may have accumulated under a leadfoot (I thought they all lived here in Oz!) so you may wish to clear these and start anew. My view is that if if the rear wheels spin (even for only a second), you have no binding brakes issue. My advice? Read up here as much as you can absorb . . . then drive her , and enjoy!

Cheers,
:icon_beerchug:

Hello,

Thank you so much for your very comprehensive answer!
And sorry for my very late one ^^.

I red all the stickys, I'm ready if there is any kind of problem on my big cat, thanks to all the forum members!

I agree, the car is really great for country touring roads, and still in cities little roads, even if the ZF auto gearbox has sometimes some little jolts while from going from full stop. Very acceptable!
But you evoke the fact that it's possible to reset its old habits, and make it learn from your own habits... What's the procedure?

And yes, all 2008 cars are 2007, as they stoped producing it at the end of 2007! It's still nice to know that they are the last ones made and so "supposedly" the most reliable...

For now, everything's fine, I'm just struggling with my two key fob, remote randomly working... tested the PCB and changed all the buttons, but sometimes work, sometimes not... 🤪

Have a nice weekend!

Guillaume

You would reset the adaptations (*) - needs a tool capable of that such as IDS/SDD.

(*) they are stored in the TCM and not cleared by disconnecting the battery

Hello, Guillaume:

It is unlikely that the EPB remaining activated is causing your perceived fuel economy issues; that said, the 2.7 diesel version of the S-type was not sold on North America... so, this may not be the best place to seek information on your particular vehicle (at least in terms of engine related matters).

You might want to make your inquiry here (where there are a number of members who own the diesel variant of the S-type):

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