Hi My Beloved Jag 2003 XKR 4.2 just failed on the long trip .
Nothing untoward occur on ly fault was engine stalled doing a 3 point tunr in a street . runing ok before with no faults showing . Mechanic advised left side of engine has compression of only 55-7- right side 140- 170 . Fuel seems to be by passing somehow valves or rings ?
I did notice prior that vehicle was fumey when accelerating passing other cars .
I have recently replaced injectors and installed slightly smaller pulley on super charger so assumed remapping maybe required ?
Anyways Jag is on a truck making its way home ..looking for answers thanks

 

Mapping is not required, Jaguar's maps are fine up to 650bhp.

More likely is a head gasket. The 4.2 has steel liners so it doesn't suffer bore problems of the early 4.0 units. Did the engine temp spike at all?

I would look into the 'new injectors' - they may not be compatible.

 

Hi Sean , Thank you for the prompt feed back.
In regards to the mapping am i to assume the computer automatically adjusts any changes made to the engine ie smaller pulley slightly different injectors etc ?
To my knowledge the car hadn't overheated ( Showed no signs on gauges ,smells or faults in fact we had just traveled 1800 klm's the 2 days before without a hiccup.
Yes the whole reasoning for purchasing the 4.2 litre was the steel liners and other issues with tensioners etc of the 4.0 litre models .
I guess I'll be very thankful if a a head gasket is all it is..
The new injectors are these and seemed to be suitable if not better than new and i assumed ( possibly wrongly ) that would assist in performance & economy with the smaller pulley .
Reason for injector replacement was prompted by Fuel pump deciding to have a melt down and as such debris invaded the fuel lines and existing injectors full replacement more cost effective than a clean
i did note on this trip the fuel consumption was down ,getting only 27.5 mpg previously Ive managed 31 mpg on a road trip @ 60 -65 miles average



SET of EIGHT BRAND NEW UPGRADED JAGUAR FUEL INJECTOR
for Supercharged Jaguar's with 4.2L V8.

Using a brand new Original Denso injector we have develop this upgrade unit to exceed original performance of the 2W93-BANumbers on our upgrade units have been erased to avoid confusionStock flow on these injectors matches the OE specifications.

330CC/MIN 100% Duty Cycle @ 43.5 PSI

These are guaranteed to fit the listed applications and will exceed the OE injectors in overall performance and reliability. Don't be confused by the cheap Chinese knockoff injectors that simply don't work. These sets are made using quality Denso Units.



(see specific application data below
*** 12 Month Warranty ***
THE PRICE IS FOR A SET OF EIGHT INJECTORS
(The Quantity Available shown above is the number of SETS we have)Please note: these are NEW fuel injectors. They were acquired in bulk quantities and are not individually boxed for resale. They have never been installed in a vehicle and have never contacted gasoline. As the # 2 Fuel Injection Specialty Company in the USA, we frequently purchase large lots of NOS and surplus (production overrun) Brand New fuel injectors from OE sources around the globe. Some may have a nick, scratch or very minor cosmetic flaw present from transit & handling. As with our Factory Remanufactured parts, each set of New injectors is also fully bench tested & flow matched to confirm they meet all OEM specs prior to shipping. This gives you the best of both worlds …Brand New fuel injectors at Remanufactured injector prices. If you've diagnosed your problem to be injector related, this set of Brand New OEM fuel injectors will restore your car to like new performance! These fuel injectors fit the following 4.2 L V8 JaguarsReplaces OE #'s 2W93-BA, 4650544, AJ811177, AJ82532, AJ88900Site link is ; https://www.ebay.com/itm/SET-of-8-Ne...25788#viTabs_0

Any further comments much appreciated
cheers

 

lol I always laugh when people say 100% duty cycle. You cannot have this, that is static and never closed. 80% duty cycle with 10% to open and 10% to close. My 1000cc injectors in my super charged Ken Bell v6 run 75% duty cycle at 7000rpm.
On your low compression did he had oil to the cylinders to see if its a possible ring wash, which could easily happen if you have 100% always open injectors
or is it bent exhaust valves from a jump in timing that ever so slightly touched the pistons? Or did he run a combustion test on the cooling system for evidence of hydrocarbons in the coolant which would indicate and blown head gasket. Or does he know the issue is cylinder wall wash and wants to hit a head gasket job instead????

 

The picture shows 4.0 style injectors, and the static flow for stock 4.2 injectors is about 440cc with 55psi (the pressure used on 4.2 cars)

Did you use also XKR 4.2 intercoolers/intake manifolds with the 4.2 injectors, and did you change the fuel pressure or did you leave that alone?

Do you have an actual picture of the injectors you have now?

Not that this is the cause of your issues, but the info given about the injectors/setup is incompleet and incorrect.

 

Ummmmmm, I just bought AND INSTALLED the same injectors and now i am scared. I do have a lean banks 1 and 2 and even after hunting and fixing vacuum leaks Im having difficulty getting good short term fuel trim. My original injectors were a red/orange color but the "upgraded" replacements were green like these https://www.ebay.com/itm/201820425788

 

The 2006 has brown(ish) injectors, which flow about 15% (can't remember the exact %) more than the older (so pre 2006) blue injectors, which flow at least 400 at 55 psi.

330 in the advert at 43, would be about 360 at 55 psi, way to low.

Try to get you money back, and install the right injectors I would say. Injectors is not something you should play with, you took a big risk here imho.

 

I agree 100% and the info you posted along with the fuel trims on the grren/blues one I posted in a different thread proves these injectors are flowing about 10% to 15% less than the red ones causing me a lean condition.

I have contacted the seller and told him they are not right for my car and want a refund/ I will have my originals cleaned and re-installed. thank you! your information is highly valued and appreciated!