Did You have same kind of problems of car staying in open loop ?
What Andy did to Your EPROMs ?

 

No. I don't believe it can. I thought it would, but I would not bet on it. It can't seem to do very much on an AJ16 engine. I think it really is designed for the cars introduced right after.

I'm sorry for mentioning this item.

 

Shall we play ?

*NEWEST* PCB6.0 EPROM programmer, BIOS, PIC, Designed in the USA !ShipfromUSA !

The 2 EPROMS are STmicroelectronics M27C512-12B3 /32 and 28 pin on Ebay for a set to play with . The ECU hardware and firmware should be the same for all configurations just different maps .

https://www.alliedelec.com/m/d/5ab16...29b8594e5f.pdf

http://www.gomog.com/allmorgan/GEMS/GEMSbyPoole.pdf ( 8 cylinder version of Lucas GEMS 6 , mine is part #LNB 1210 AD/--- pre TSB R493 for US cars )

 

Would incomplete O2 sensor emission readiness test cause car to run open loop ?
I tried to do the oxygen sensor drive cycle today it didn't complete the O2 sensor emission readiness test, but now the car is running lean on idle (17 AFR when measured with wideband lambda. Also Torque reports them as 0.1 Volts which means they are closer to 5V when measured from sensor.
When I give constant throttle to engine it goes rich but comes back down when throttle is closed.

 

Not sure about the readiness test preventing the car from going open loop, but I do think it's definitely related. Obviously something is wrong at the O2 sensors, and that is one of the sensors that is required for the ECU to go open loop.

The O2 sensors after the cat is what makes all the adjustments to the fueling Trims. The ones you don't have, which are the ones before the cat are just there to make sure the after sensors are functioning properly. As long as the readings at the pre-cat sensors are higher than the post-cat sensors, everything is fine. I admit, it's certainly a strange setup, but this is indeed the case.

I don't know how this works In countries/cars that never went to the four O2 sensor setup.

Has the car worked properly before. Has this only happened once you removed the cats?

 

When I got the car manifolds were badly cracked and due to the car running constantly rich front cats were badly blocked.
I changed plugs, which were black as night, thermostat which was sticking, MAF which was dead, manifolds (non cracked but used parts) and oxygen sensors.
At same time I decided to remove front cats as the car should pass the MOT with 2 cats only anyway and maybe removing heavy cats from manifolds might give them little more living space.
I also mounted bigger crankshaft pulley for S/C and Andys 5 degree offsetted CPS mount.
So I don't know how the car has worked before all those parts have failed, but as long as I have owned it it has been on.

 

A brief overview of the X300 4 x O2 sensor setup is on page 36 , 55 and 80 . You might find some other useful information like requirements for close loop . Are you currently with a installed fwd cat and plan on later going no fwd cat as I wish to do with mine ? I know it's alot of work but if you were to reinstall the cats and get the engine regulation squared then later reinstalling the no cat configuration you have a better chance of building it out to what you want . If there are leaks at the donut gasket the STFT will go rich as believe it or not fresh high O2 will be sucked in biasing the O2 readings . The donut gasket flange on the downpipe can be damaged during installation and you will be able to see it as it is removed . The new downpipe may have a flaw in the building of this flange as well . But putting some lube on the threads of the studs you might be able to seat the gaskets better to overcome this if it is the case . The original cats as they are off can be cleaned with citric acid solution in one of those large plastic buckets from the hardware store and dunking alot as mine fit and remove alot of material that may be effecting your readings . A step further would be to later use a oxylic acid solution to leach it further but you can go to far and remove the platinum alloys . You may have lost the Long term Fuel Trim stored in the ECU and would take exercising the engine to relearn it as this may be throwing you off in troubleshooting . The O2 sensor connectors can be easily swapped to the wrong positions as well . I'll get you the wire color positions later .

http://www.jagrepair.com/images/Trai...20-%202000.pdf

 

I'm currently without FWD cat. There's lot of bedtime reading on that manual. Thank You

 

Close loop requirements are I believe on page 39

 

Oygen sensors are right way as I tested them by unplugging the one connected to 1-3 cylinder downpipe and bank 1 lambda went to 0.

Wouldn't it still go to closed loop even if LTFT is way off. Car is idling nicely at 680 RPM so I don't think the fueling is so badly off.

 

This is directly from manual that Lady Penelope posted earlier.

This is for AJ6 I couldn't find same kind of list for AJ16

Closed loop operation
In order to significantly reduce exhaust emis-
sion, the exhaust system incorporates 3-way
catalytic converters that oxidize CO and HC,
and reduce NOx. These converters operate
efficiently only if engine combustion is as com-
plete as possible. It is generally accepted that
optimum combustion occurs with an air / fuel
ratio of 14.7 : 1 (Lambda = 1). A closed loop
system between fuel injection, ECM control
and exhaust oxygen content feedback is used
to maintain the air / fuel ratio as close to 14.7 : 1
as possible.
In response to the oxygen sensor voltage, the
ECM continuously drives the air / fuel ratio
rich-lean-rich by adding to, or subtracting from,
the injector pulse duration determined from
the main fuel metering strategy.
Note that the oxygen sensor voltage switches
abruptly at an air / fuel ratio of 14.7 : 1 (Lambda = 1).
Closed loop operation is canceled by the ECM
during the following functions:
• full load enrichment
• after-start enrichment
• warm-up (below 95°F [35°C])
• deceleration fuel cut-off

Any of those shouldn't be effective

There was also confirmation for US/Canada models that after cat sensor are used for fueling control

"The ECM uses the upstream catalyst oxygen sensor signals to provide closed loop injector control (except AJ16)"

 

LTFT is a math formula the ECU runs, it will not affect your cars ability to go open loop.

Your nice idle is a result of no vacuum leaks. I'm afraid that remaining in closed loop means that your idle situation is being set according to a preset program. I'm not surprised your idle is good.

I'm sorry if I'm asking a redundant question, but did your car ever have 4 oxygen sensors?

 

No. European version of AJ16 only have 2 oxygen sensors. one on each downpipe just after catalysator.

 

Ref page 96 of the Jaguar 801s document the EGR valve feedback is one perimeters for closed loop . Clean connector at both ECU and EGR valve ? Let me develop a function test . Rest of World according to wiring schematic does not have a EGR valve just North American Federal , nevermind . SC engine All of World in your case does , so game on . You can put the print on a flash drive and the print or office supply store can print any size . Are you seeing 0.7 volts at idle and above at throttle up with the proper PID or you can tap into a test point on wire Red /Pink as it runs over fuel rail . Is the actuator a variable position with variable of momentary driving voltage or simply open/close ? You can drive the actuator from the ECU connectors with a 9 volt battery and read resistance change of the followup sensor through sockets Red 11 and Red 15 .

Black 24 = Solenoid actuator ground or power to drive the other direction ( wring out sheet missing this pin )

Black 35 = Solenoid actuator power 0 - 9 volts

Red 7 = Sensor ground

Red 11 = 5.0 reference voltage from ECU

Red 15 = Signal back to ECU

 

Page 155 for AJ6 engine shows the coolent temp must be above 94F or 35C . Warm up period long enough ?

 

There is no EGR and no Air Injection either here
Engine temp is also over 89 degrees Celcius. I ordered IDS version 125.03 and Mongoose interface so we can shed more light into this case.

 

If we accept that one of the requirements for closed loop operations is a temperature of 95, then the fact that the OBD reading is 91, and the OBD says the system is in open loop because of low temperature must surely be two pretty compelling clues?

 

Yes but the temperature units used on my posts are in celcius.
91 C is about 195.8 F

 

Might try a 1.0 K resistor to simulate a coolant temp above 110 F or 45 C and not too far out like a open free air connector or a shorted connector . If the sensor input into the ECU is too far out of range it my be seen as invalid data because there is no map for that Temp and rejected not allowing closed loop .

 

If you just connect the two ends of the plug end, you'll get to a max reading. No need to mess with resistors. Unplug it from the sensor and connect the ends of that plug with a paper clip or something.