No problem. Take your time. The more data, the better the results...

 

You haven't replaced the oxygen sensors, have you?

 

I have not replaced the Oxygen Sensors.

So far three (3) days of no engine light w/temp sensor shorted.

My code reader only shows the OL & CL after the fault has occurred.


Thanks

Softball60/Paul

 

Let's start with replacing the Coolant Sensor. LHE1600AA. It's an easy part to find. I don't think this is a part that you need to get from the dealer or from the OEM manufacturer.

Does the reader show CL for both banks when driving for awhile?

 

Bought a Bosch Temp Sensor. Will take ~ 5 days to arrive. Will let you know as soon as it arrives.

One (1) other note I forgot to mention. Mabye coincidence... If I tried to start the car after the engine light came on.....It's sounded like the starter motor and the flywheel were slightly off ....and I got that metal to metal sound.

This only happened a couple of times during all of the Engine light issue. Don't know if this is part of the whole issue.

Softball60/Paul

 

Vee,

Installed the temp sensor. Drove the car and the "Engine Light went on".

Today I will warm up first then drive to check if light goes on.

The engine codes were the same as displayed previously when the Engine light came on, in the past.

It listed multiple misfires and one bank of plugs open and the other closed.

Noticed that the idle dropped back to normal 650rpm's and the transmission shift pattern seemed to be less aggressive "Normal" going through the acceleration.

When the temp sensor was disconnected and shorted the idle was just slightly higher and the shift pattern was more aggressive "Sport".



Softball60/Paul

 

The next suspect is the oxygen sensors.


They are easy to access. If you wanted to run a test without spending money, you would switch the two sets to see if the OL/CL switches too. Bank 1 is currently Open and Bank 2 is Closed. If you were to switch the sensors, then Bank 1 would remain Closed and Bank 2 would be Open.


Can you do that? You have four sensors, I recall them being just under $100 a piece. If you could run this test, it would save you some money. If they are original to the car, it's probably time they were changed anyways.

 

How difficult? I'm game but may take some time.

Any suggestions for working on this issue is appreciated.

Softball60/Paul

 

Paul,

I'm guessing from what Vee has said that US AJ16 cars have 4 sensors, whereas there are only 2 fitted on standard UK cars.

I don't know where the downstream ones are plugged into on US cars, but on UK cars, the standard 2 upstream sensors have their connection above the engine near the bulkhead. It's fairly easy to unplug them and swap them over.

If you know someone with the diagnostic tool and software, you can "swap" them over using the software, rather than physically swap the plugs.

Good luck

Paul

 

PTJS1

Thanks,

I have been looking as to where all four (4) are located. How long should it take to swap them front to rear.

I do not have the electronics programming to swap.....So I will have to do mechanically.

Thanks

 

Just a word of advice here, boys. This is and AJ16, it uses Titanium Dioxide O2 sensors. They are in no way similar to sensors on any other Jaguar.
1. They are more like $500 ea., not $100.
2. They are backwards from other engines. Here the upstream are used to monitor catalysts, the downstream are used for fueling decisions by the ECM.

The concern should be which cylinders are setting misfire faults and investigating that. That is likely why one bank shows open loop. So far I see no statements that are any O2 sensor faults recorded. Unless there are O2 related faults, I wouldn't go there. It will only cost money and time.

Shorting the coolant temp sensor only clouds the issue as well. That likely only forces the ECM to substitute a 'default' value for the sensor. When that happens everything operates on defaults, and the O2 sensor aren't even being used for fueling.

Cheers,

 

I bought 4 O2 sensors for my 96 XJS from CarParts.com for a total price under $135.00 and installed them in May. I don't drive the car very much, but so far no faults or problems. Are you saying that these sensors are not correct for my car? How would I know if the ECM was in default mode? Thanks.

 

Just a note....

I flipped the sensors from front to rear.....All four (4) look exactly the same.
Tomorrow morning I will fire the car up and drive to see if the Engine Light comes on.

I drove it immediately after changing positions. Car was still warm ....not hot.


It ran great.... No failure Engine Code.

I will check when the engine is completely cold.

Thanks

Softball60/Paul

 

Paul,

When you say that you've switched "front to back" I assume that you mean that you've switched the 2 upstreams over then switched the 2 downstreams over? By doing this you've switched the "front 3 cylinders" to the "back 3 cylinders". You don't want to switch the upstream sensors to the downstream sensors.

Hope that makes sense

Paul

 

First of all here are two brands of oxygen sensors that work fine for the 96 XJS and are both under $100 each:

https://www.amazon.com/gp/aw/d/B000CF1W5A/ref=mp_s_a_1_4?ie=UTF8&qid=1474921670&sr=1-4&pi=AC_SX236_SY340_QL65&vehicle=1996-20-100-------------0&dpPl=1&dpID=31A0VRHYHCL&ref=plSrch

https://www.amazon.com/gp/aw/d/B001PNE958/ref=mp_s_a_1_5?ie=UTF8&qid=1474921670&sr=1-5&pi=AC_SX236_SY340_QL65&vehicle=1996-20-100-------------0&dpPl=1&dpID=31LwR79ws5L&ref=plSrch

Both work, I can vouch for that. I also know that they are both stamped "Made by NTK". The OEM Denso sensors are also stamped that way too. By the way, the car uses the same exact oxygen sensor in four places, so they are interchangeable.

Secondly, I was hoping you'd switch upstream with the other upstream and downstream with the other downstream, so that you could replicate the bank staying closer to the other bank. I wanted the bank that went open (Bank 1, I think) to stay closed, while creating a situation where the Bank that previously stayed closed to now open. That would indicate a definite issue with the oxygen sensors.

I am suspecting first the coolant temp sensor, then the oxygen sensors because those are two values that the car checks for before going to open loop. If one bank is staying in closed loop, that means the ECU is not satisfied with the info it's receiving.

It's possible that the oxygen sensor has become lazy, enough to prevent the car from going into open loop, but not enough to trigger a trouble code. This engine is notoriously stingy with its willingness to dole out codes that help to easily diagnose parts going bad. (Coils going bad are usually never tipped off by triggering a P030x code, although they should!)

I'm just trying to help diagnose the issue systematically by eliminating the suspected failing part one by one.

I'm sorry I was vague on which sensors to swap.

 

I took the top two (2) sensors closest/front to the exhaust manifold and placed them in the bottom/back two (2) and vice-versa.

All four (4) sensors looked identical.

I drove the car immediately after I finished. Didn't seem to be any issues and the Engine light did not come on.

What is the potential problem as to which you are referring?

Hopefully I didn't screw this up.

Softball60/Paul

 

Paul,

I THINK that what you've done is swap the upstream sensors with the downstream (rather than swap the two upstream with each other and then swap the two downstream with each other). This is not what Vee was suggesting. If this is what you have done, you do need to reverse this.

If I were you, I would;

- Put all the plugs back exactly where they originally sat. Mark the wires with tape so you don't get confused later
- Find the two upstream sensors (located in the downpipe after the exhaust manifold.
- Follow the wires of these two sensors up to their plug connections.
- Now swap these two. You have now swapped the upstream sensors
- Now swap over the other two plugs. You have now swapped over the downstream sensors.

Good luck

Paul

 

Thanks ptjs1,

I'm afraid I screwed up!!!! and I didn't mark the wires.

Here's what I will suggest since I don't know what wires go where.

1. Start the car up tomorrow morning and drive cold. See if I get any codes. I will check to see if it was the same as my previous misfire codes. If I do get the same misfire codes, I will switch the plug ends of the connectors.

I am going to assume this will be okay since all four (4) sensors are identical.


When Engine Light originally came on
Previous reading was: Fuel System #1 was OL & Fuel System #2 was CL

Softball60/Paul

 

The in-car O2 connectors have color coded wires. If you have a wiring diagram, you can verify that the sensors are connected to the correct connectors. I had the downstream sensors reversed and was getting a fault code after replacing the converters. The fault disappeared when the sensors were connected correctly.

 

I'm going to do what I had mentioned in my last post.

Hopefully the car won't come unglued!!!!! Ican revert back to what you are saying after I check it out tomorrow.

Thanks
Softball60/Paul