Maybe better chart modified from someone's original

 

will record some video of the app later.
atm i took off my valve cover to redo the seals as there was a small amount of oil entering the sparkplug wells.
will be monday before i can run the car again i think.....

what i did see when looking was that the STFT was going a bit erratic all over the place.
reading anything from -15 to 15
will make sure settings are right and that i am looking at the correct sensors.
car may potentially be running rich all the time.
but only rich enough to cause issues at cold start

for the AU model with only 2 sensors is it bank 1 sensor 1 and bank 2 sensor 1?
or do i just look at bank 1 and bank 2?
there are many different readings under fuel trims and wanna make sure i am reading the right ones.

 

The STFT does move all the time. It is Short Term, therefore, as long as it's moving around, its fine. The Long Term is more helpful in diagnosing issues, but not in your case....and also the 1995 LTFT seem to wander way out of parameter anyways. In any case, thats neither here nor there.

I think you might just have a dud ECU. When is say dud, there's something off about the fueling maps that the car is using when cold and in closed loop. (I realized I goofed in my earlier post, swapping open for closed and vice versa) Maybe someone sold you a 3.2L ECU?

 

You should only have bank 1 and bank 2 fuel trims , there is a long term and short term , you want short term

You should only have B1 S2 and B2 S2 for rear sensors in the pic below

With it running rich for such a long time may have to run hard on the HI way to clean up sensors of carbon to read better and better result otherwise chasing bad information

ECU Jaguar part # per Vee's suggestion as you mostly have 3.2 liters in Australia from my understanding

With a vac leak you would go from neg fuel trim toward 0 only related to higher RPM and not hot / cold

 

Will check more on monday once car is back together.
seems to be a mix of 3.2 and 4.0.
i personally would have thought more 4.0 here but not really sure.

 

The hardware and stuff inside all the ECUs are the same ( V - 12 is a Denso manufacture so it would be obvious ) , it is the software that is different like Eprom maps or data arrays for the different displacements and supercharging

There is 2 Eproms ( easy pull and plug ) that " might " get you back to 4.0 regulation on one of your ECUs

This solves shipping cost and time to England and is covered under the R - 493 TSB

Possibly why it is over fueling as a too long / longer injector pulse width , but you have 4.0 , so that would be wrong , but got you thinking as a Jaguar X300 problem solver

Looking for your specific 4.0 ECU for Australia

Just say no to vegemite , one bite while I was there and I knew my vegemite days were over

Most of your 4.0 liter original factory ECU differences are in relation to the world counties emission regulations ( EGR regulation being one of them you do not have )

XJREngineer would know more about it and starter immobilization / enables which he can blank , USA X300 models and ECUs do not have chip in key immobilization

Genuine Electronic Control Module-4.0 Litre (4.0 Litre,4.0 Litre (california)) For Jaguar Xj 1995 - 1997 (from 720125 To 812255) (x300) Classic | Jaguar Land Rover Classic Parts

 

I'm wondering if it is either a bad MAF. Other thought is fuel pressure is too high due to a faulty regulator.

As the engine is running on tables without feedback until it's warm, I'm thinking of what sensors it uses before correction is applied. We can probably rule out coolant, so that leaves MAF, or if MAF is correct the fuel pressure is higher than expected and therefore injects too much fuel. Once in closed loop the system can bias it back to a correct mixture

 

I also believe the fuel pressure requires checking, Parker also mentioned that previously.
A faulty fuel pressure regulator will certainly cause over fuelling from my own experience and it is a relatively easy fix.
I have a previous post which sets out an easy installation which is left in the fuel hose for easy reference.

John Herbert
1996 XJR

 

i took the ECU out of a 4.0L car.
4.0L N/A LNA1410CF/301 (original for my car)
4.0L N/A LNA1410 WB/301 (from parts car)
not sure exactly what the GF and WB mean for differences.
but the 301 is what i read was most important part to be same.

 

i did think maybe FPR. i do not have a gauge to check it, i did swap it out from my parts car and did not see anything different.

 

Thanks for the email too.
problem is that i can not install a gauge like you have.
the N/A does not have the rubber fuel line.
that is where the Fuel Pressure Regulator sits and it has metal lines running in and out of it.

not sure where or how to install a gauge or where i would even connect a test kit to check.

wonder if OBD fusion gives accurate fuel pressure readings

 

The original car does not have a fuel pressure gauge so no direct reading

For the Fusion to give you something it has to be calculated backwards based on some not so accurate assumptions , very inaccurate in the real world

Your test point is the fitting pointing fwd or at the rear of the fuel rail going all the way back to the fuel pump itself , this is where you need to use the 2 wrench method and not just single least twisting the fuel rail

The " Australian " fitting I once saw was at the rear of the fuel rail as more room to work with , maybe a T fitting , my fitting was to drill a hole on the fwd FPR hex on the FPR side which sacrifices it to not be able to reseal the hole

 

what is the diameter and thread on the fuel line there?

 

Where the finger is a weird type of fitting more like a toilet tank fitting as a curved ball that seals , probably the same on the fuel rail rear fitting

I had my fuel rail completely off before so recollecting and tried to come up with something here in the states but no joy

 

X300 Fuel Pressure Test Kit Fittings - X300 - Jag-lovers Forums

Jaguar SnapOn adapter tool JD 208 (MT 337A) for checking X300 fuel pressure - Jaguar Forums - Jaguar Enthusiasts Forum

 

So as there is no rubber line to cut into i guess i would be looking to install back here.

so that is fuel in before it gets to injectors
i assume exact same reading as at the other end of the line.
unless the injectors cause a slight loss in pressure.
but that makes no sense cus pressure would equalise

m14 x1.5 seems to be what i need to make it happen

 

Ok so STFT are imbalanced between the two banks.
could this potentially indicate that there is a leaky injector?
or an injector opening too far?
or dirty injectors resulting in car trying to send more fuel to compensate?


note the app is laggy and there is delay from accelerating to it adjusting the gauge. seems it does not poll often enough to give exact smooth readings.

 

Does the STFT behave the same in closed loop 88 C or above ?

with the O2 sensors in the loop the same injectors ( if good ) may see a shift and more stable ?

There may be a way to average your readings ( dampening ) and not see a snapshot , snapshot I would expect to see change a lot as the ECU recalculate things ( injector pulse width with the O2 sensors when in use ) but you're not using them below 88 C

 

readings were all over regardless.
when i went for a drive bank 1 was often reading -15% to -20%.
but was also going back to around 0 or normal.
it was always reading richer than bank 2.
i expect them to change often also. but i am sure that there would be a certain range that would be expected?
and you would expect to see bank 1 and bank 2 as kinda same same?

it seems that maybe one or more injectors is dumping too much petrol and then the ECU does what it can to compensate?
really not sure.
i am just trying to apply logical thinking here.
this is new territory for me.

also went looking today for a fuel pressure gauge and adapter and can't find anything.
seems that m14 1.5 flanged adapter is not easy to find

 

" when i went for a drive bank 1 was often reading -15% to -20%. "

Not a sign that is went into closed loop

Was it when you backed off the throttle ? sign of exhaust manifold

88 C coolant temp ?

If it did go into closed loop I would expect bad ( high or low ) fuel pressure would be compensated to a certain limit by changing the pulse width to bring your STFT closer to target 0

So this makes you look away from the FPR as there is another factor , and you have swapped them , so the odds are..........

Did you ever do an exhaust manifold check for cracks , leaking or just loose downpipe donut gaskets ? Loose nuts have been found

Bank 1 being more negative than bank 2 points to bank 1 / 3 port section of exhaust manifold