now i know this is a big open ended question with a whole host off possible causes.
what i am looking for tho is kind of a where to start.
i can just start throwing parts canon at it but that gets expensive, fast.
right now i am sitting at 17-18L/100Km.
i can smell it running rich and there is some moist splutter that comes from the exhaust so it is clearly running rich. just gotta work out why.
and yes i only ever fill it with the premium 98 octane.

now i have recently replaced the spark plugs.
i am planning to get a andy bracket soon, just havn't organised it.

so what would be suggestions on where to start . what is most likely to have the biggest impact, most likely to be broke, and / or cheapest to parts cannon.

i know the ignition coils are old and worn. saw the condition of those when i did my valv cover and spark plugs.
o2 sensors, there is two of those and should both be cheap enough and easy to replace if i am not mistaken.

i assume clean MAF and TB,
now there are 2 sensors (plugs of some sort) on the air intake pipe, i assume these are todo with reading airflow for air fuel mix, but what exactly are they and how likely are they to need replacing?

fuel filter is probably a good easy change (gotta find where it is. lol)
i know its a lot of maybve this maybe that, i am just trying to wrap my head around where to start, not looking for exact answers

 

G’day Spud,

If your engine starts and runs well when cold and gradually gets worse as it warms up then a dodgy coolant temperature sensor could be to blame. The coolant temp signal to the ECU has a huge effect on the fuel injection scheduling.

My V12 gets around 16ltrs / 100 around town and 12ish on the freeway.

Cheers,
Jeff.

 

Get a cheap code reader and check the voltage of the lambdas when the car is running - if they are bad fuel consumption goes through the roof.
An easy sign to look for without the code reader is the engine idling badly after warming up, same as with the bad temp sensor.

 

just recently changed the coolant temp sensor actually. as i was thinking that might be an issue and saw it as a cheap easy fix.
crazy to think your v12 is doing a bit better than my i6.
i suppose my next point of call needs to be the ignition coils and then maybe the o2 sensors.

 

do you know if this can be read by an elm327 bluetooth adapter and the torque app?
also do you know the part numbers for the o2 sensors?
hard to say if it's idling badly as i don't know exactly what good idling should be for these.
i wouldn't say it climbs or drops a large amount or too quick, but there is fluctuations in the idle that can be felt.
its not exactly what i would say is "smooth"

 

if you can feel the occasional judder of a misfire at idle then that would be considered a bad idle.
i use a elm327 wifi and OBD fusion (since i have an iphone) so torque and a bluetooth adapeter should do the trick.

here is a link to the sensors
https://www.britishparts.co.uk/class...n-sensor-p7158

 

So this is what i was also curious about.
so the first circle would be the MAF
what is the second sensor thing i have circled?
and whatbis the exact purpose if the black box i have circled?

 

The red circle is the inlet air temp sensor and can be fouled with guck on the temp bulb that throws off an accurate reading

this has some bearing on the fuel mixture

the yellow is the resonator

on your engine coolant temp sensor, it should get past 88 degree C for the ECU to go into closed loop mode

see this link , post # 55

Failed emissions test (CO at idle) - Page 3 - Jaguar Forums - Jaguar Enthusiasts Forum

Have you checked the ECU connector for corrosion?

the O2 sensor connectors can get corrosion inside and the sensor heaters ( for them to even function ) can be easily checked along with the one fuse for all 2/4 sensors fuse # 14 / 10 amp right engine bay fuse box

cleaned multiple engine grounds including dedicated ECU ground strap on the ECU case and the big engine block / starter strap ?

 

Is there any point to an enginebay resonator delete?
does it run better?
sound better?

 

o2s get lazy over time.

titania sensors are different in how they work and are harder to diag. there’s only two of them on your car so just fire the parts cannon


also 95 ron only, it cannot advance enough to take advantage of premium. 98 is flushing cash away

 

Bosch connector ready sensor part # 13789 is a cheaper alternative to the original Denso

The O2 sensor diagnoses trouble can be from the device not recognizing the signal of the titanium sensor vs. a more common Zirconium as they do work differently

Watch for proper connector position installation as they can be swapped in your resent history

the sensitive sensor signal is protected from external interference by a shielded wire ground terminal post on the rear engine firewall as the small terminal post

 

How old are your oxygen sensors? Thats the first place I'd look.

Don't know the answer? Replace them. They are not forever parts, they wear like brake pads.

 

yep have ordered some now. Just gotta wait for them to come

 

When I purchased M'Lady P one of the aft sensors can shape was smashed by a pair of pliers and the wires where broken and sticking out the insulation at the sensor

The wires are galvanized and brittle if not allowed to spin freely at the upper connector installation

The connector on the car side and not the pigtail is the key to it's proper position

3 of the 4 wire group have the same color and is the 4th ECU return wire that is the difference

17 mm hex

don't forget the crush washer as this seems to make a difference in them reading correctly

the crush washer can be obtained from a cheap copper spark plug that is different in size then your spark plugs so they are 12 mm on the sensor

 

whats this about 4 O2 sensors?
over this side of the pond there is only the 2 pre cat sensors if i am not mistaken.

also i see people mentioning that the jag uses Titania sensors.
when i went to buy them here they are Zirconia Sensors.

is it maybe just a US market thing that uses the Titania just how it seems it is a US market thing they have 4 sensors?

 

I’m pretty sure you’ll be needing Titania sensors. There’s nothing in any service manual I’ve read that hints at any options here. Not for the AJ16 engine.

 

yeah that was exactly my fear.
the part i have showed above is what i have ordered as it is what comes up in the system when my vin number is searched.
so according to my vin# this is the correct part, however once i got home and realized the actual part number i got confused.
the shop searched my vin and then ordered based on that.
but now looking i can see the plugs are different to what i would have expected. i am really really confused.
god damn it man. you order parts based on vin# to ensure you get correct parts. now i gotta hope i can get these returned as they are a special order item.
as you can see in my pics above when my rego is searched on the NTK site it shows these parts *** being suitable for my car but they really are not.

just put some pics here to clarify.
so the 02 sensors are as shown
and the plugs are as shown. how can i tell if they are plugged in to the right plug??

this is the part it shows and its clearly not what is needed.
god damn its frustrating.

so this is the wrong god damn part that comes up when my car is searched. not helpful at all.

so to make 100%^ sure this is the location of the o2 sensors

and this is where they plug in? how do you know which one plugs into which plug?

 

can someone confirm the correct part number for me.
i think it is NTK OTD3J-5B1

ok so i think this one is the correct one>
this is doing my head in when i search on all these sites it is getting really confusing with models a bunch of different sites are listing parts with wrong fitment.
one site say xxxx fits another say it does not and that yyyy fits.

 

yes that is the correct connector.

any 4-wire titania will work if you crimp on the right connector.


they first one they sold you is for an xj40 (up to 94). it has the main signal wires and then a heater connector hanging out the side

 

Whatever is an as equal to Bosch 13789

NTK part shows 25018