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What are the conditions that S/C AJ16 engine goes to closed loop control ?
Mine isn't going to closed loop and lambda voltage on both banks is about 1.25 volts dropping down when throttle is opened but going back to over 1v.
My engine is running rich 13-13.5 AFR, when measured with wide band lambda
Engine has reached temperature above 89 degrees celsius.
Should there be evident lambda fluctuation going between 0V-1V ?
Also there are no codes.
Here is the picture from Android APP torque. The Lambda voltage is constantly above 1.2 V only going down when throttle is quickly opened and closed.
It always says open loop (low temp).
I'm totally lost here. It's running rich according to external wideband lambda and also plugs and lambda sensors get nice black coverage.
Vacuum leak on the intake manifold side ? Damaged donut gaskets and or gasket flange on exhaust downpipes before O2 sensors ? Sucks in fresh high O2 between pulses as the pulse has mass and draws in air as the mass slug goes down the line . The O2 sensors can be cleaned with a soaking in gasoline for there is a point where they get clouded over and no longer read accurately in troubleshooting and driveability . Look for STFT as a PID and negate speed .
Last edited by Lady Penelope; Aug 21, 2017 at 12:30 AM.
Closed loop with lambda oscillations should happen not long after cold start. You've probably got a dead coolant temperature sensor. The ECU thinks the engine is cold and fuels rich, while not allowing closed loop.
The coolant temperature display is operated from a different switch, so it shows the real coolant temperature.
Look on top of the thermostat housing - the temperature sensor has the two wire plug going to it. Easy and inexpensive to replace. Part # LHE1600AA.
Last edited by SleekJag12; Aug 21, 2017 at 02:55 AM.
Reason: Added part #.
The leak at the exhaust theory is a good shout in relation to rich running in closed loop, but the issue seems to be that it sticks in open loop. In open loop the mixture will be rich, so this needs to be resolved first.
The theory about broken engine temperature sensor sounds good, but shouldn't the coolant temperature from OBD be also wrong then ?
Also STFT1 and 2 are 0% but that's because car is still in open loop.
However the LTFT for both banks are -100%, but I'm not sure if it should be that way.
As I understand it, open loop is a static "map" of parameters which the car uses immediately on startup until it has been able to obtain data from all of the sensors which contribute to the ECU determining how much fuel to supply, ignition timing etc. Most particularly, the ECU doesn't have any O2 readings from the lambda sensors as the engine isn't running. Open loop tends to be towards the richer end of the spectrum in the interests of getting the car running reliably and smoothly.
Once the engine is running, and the readings to the ECU stabilise, the car should Quickly switch to closed loop operation, where the "maps" used by the ECU are based entirely on the data being supplied to it, and should result in better and more efficient operation across the range.
I don't know all of the reasons for a car sticking in open loop, but failure of any of the sensors would seem an obvious place to start. As has been suggested, the temperature sensors would be worth checking, as would the lambda sensors themselves.
If coolant sensor would be broken shouldn't the car give one of these codes in addition to OBD temperature being wrong ?
Lambda sensors have been changed couple of months ago and I cleaned them yesterday in ultrasonic washer with vinegar because they were lightly covered in soot.
Problem is very hard to comprehend because there are no error codes at all and all data from OBD seem plausible.
There are two coolant temperature sensors, one to drive the gauge and one to drive the ecu. Looking at how perfect your temperature reading is, I would be suspicious that this signal is coming from the sensor for the idiot gauge, and not the actual temperature sensor.
You can verify the sensor for the ECU input by the wire colors Blue /Yellow and Black/Brown . The wiring for the gauge is the Orange/ Pink . You can test the resistance change with a meter of the sensor by dipping it in hot water . You can use 32 degree ice water as a reference . I had the code but cleared up by cleaning the connector .
Hope this helps , Parker
Last edited by Lady Penelope; Aug 22, 2017 at 11:34 AM.
I pulled the plug from 2 wire temperature sensor and immediately temperature display on Torque dropped to -40 degrees celsius. That verifies that Torque is monitoring correct sensor and it seems to be working.
So problem has to be somewhere else.
I tested if I can get the car to closed loop by increasing the temperature ECU measures. So I inserted 150 Ohm resistor to temperature sensor socket between those two wires and OBD shows that engine temp is 107 degrees celcius but still no closed loop.
Apparently static fueling map was leaned somewhat by "increased" temperature, because bank 2 lambda was showing some crossings between 0-1 volts.
Which program can be used to do adaptation for the o2 sensors, gas pedal and TPS for -95 XJR ?
PDU of course but it's impossible to get so are there any other alternatives ?
Which program can be used to do adaptation for the o2 sensors, gas pedal and TPS for -95 XJR ?
PDU of course but it's impossible to get so are there any other alternatives ?
Most Jaguar equipped software can do the O2 sensor orientation. WDS/IDS can certainly do it. The PDU is not needed for this.
I believe v127 or perhaps v129 was the earliest. IDS much older than that doesn't work for these engine because they were not designed to be read/adjusted by what is now the standard OBD2 cables.
It does not matter to you unless you plan on acquiring a mongoose. I had a clone and it worked sometimes, and then it stopped. Back then I paid about $150 for the clone and program. The program didn't work at first, then I was emailed more versions until v131. That seemed to work....sometimes.
Now I no longer have the laptop, nor do I have a functioning version of the program.
Either buy the mongoose, or find a functioning WDS.
Or you can go to any shop equipped with the Jag specific software and have them do it. They shouldn't charge you more than 1 hours labor. It doesn't take 20 minutes to perform, including the throttle potentiometer reset.
Closed loop lambda control
