Yea they are doing their best to put everyone out of business except themselves. And make vehicles a non repairable.

Yea i would have thought that that would lead to a different code. But it seems that whoever designed this system does not use the same logic we use.
In the pervious post i mentioned the idle air control fault. There is no idle air control on the truck nor mentioned in the manual. The manual only says the fault is from an air leak between the maf and throttle body. By my logic if its not on the truck it cant fault out so this should have shown an engine lean code not IAC code
The fault was there when i bought the truck almost 2 years ago. And the previous owner was driving it until about a month before i bought it. He sold it because of the correlation fault. I bought it an just stored it for the summer with repair plans for last winter but they didnt materialize. There was not much fuel in it to begin with and no reason for me to put more in. But since the fault already existed there was no reason the think that might be an issue. But it makes me think that the previous owner was to cheap to pay for premium fuel.

Yes im familiar with stale fuel, I run my boat as close to empty as i dare every fall for that reason. Refresh the fuel in spring by at least doubling what is in the tank. Much more noticeable on carb engines. Fuel injected engines are no where near as affected by this. Usually only suffer some power loss. There was probably only a gal or less of fuel in this thing when i dumped the 5 gal in but the fault was there when i bought the truck and it would have had fresh fuel at that point.
Its bizarre to think that stale or low octane fuel could/would cause a correlation fault, without throwing another fault. But that is the only thing i did, unless my gap tool was not properly clearing the adaptive values in previous attempts.

Well just to throw another level of insanity into this puzzle.
Updated my GAP tool and then started logging some numbers from both Rovers. I did not see anything unusual for a bit but then a second code popped up, P0507. Which comes up as Rpm high idle air control. After looking at the manual it mentions air leak between the MAF and throttle body. Yea ok, i didnt tighten the plastic intake runner. So i tightened that up, Cleared the adaptive values again and cleared the codes. Now it is miraculously fixed itself. Readings from both banks match and no MIL. Made at least three separate start attempts to see if the problem returned. I then removed the intake and reinstalled it loosely to see it the MIL comes back. Three starts later and so far it has not returned. While im not ready to call it fixed yet, i wont be able to do much with it until spring when i can actually drive it.
I have a hard time believing this is a result from a loose intake tube.
However I wonder if it is possible that this could come from the previous owner using standard 87 octane fuel. Which is not recommended on the SC models. I put 5 gal of 93 octane into the truck this morning before doing anything This is the first time i have put fuel in this truck in almost 2 years. And knew about the fault when i purchased the truck.
Latest readings.
https://drive.google.com/file/d/16R7iTCNvlFe9FOJ8zxcBly-yhMDk6dj-/view?usp=drive_link

I had considered that the tool may be scaled incorrectly. I assume that the scaling is a function of the tool not the ECU. Which may or may not be the case. I am going to do some direct comparisons this weekend on both Rovers. Maybe i can spot something. If not i will re-evaluate how to continue. Maybe I need to purchase another diag tool or possibly a scope.
Any information on suggested diag tools would be helpful. I keep seeing this SSD tool mentioned but cant find any information on it. I would like to know what that one is.
As for a scope, the Pico Scope is one that i have eyeballed but not sure which model i would need.

Yea i just realized that the math doesn't work. Unfortunately I do not have another OBD unit that can read this data. I do wonder if the numbers are due to the reader and not actual position. Regardless we can see from the good Rover graph that both banks should be the same. And from the faulty one the variable valve timing pair are relatively close to each other. The variations i suspect are a result of the ecu compensating from a fault of some type.
Did you get access to both graphs now?

Just some speculation here
There is one way the numbers would make sense. If we consider that a full cycle is 1 rotation of the cam but 2 rotations of the crank . If we set 0-360 degrees of cam rotation when the crank is at BDC between compression and exhaust. Then 90 degrees of cam rotation = 180 degrees of crank rotation. With the intake valve timing at 60 degrees it would be 90-60=30. Then 30/2 = 15 degrees actual BTDC at the crank. This would also account for the "retarded" timing number. Since 50 degrees of cam angle would equal 90-50=40 then 40/2=20 degrees actual BTDC at the crank.

Fixed the graph, i forgot to set the share.
Yes The numbers dont make sense. 65 degrees for valve timing is not viable, however nor does 1 degree. What else does not make sense is that the timing would retard rather than advance. If i remember from years ago a high rpm cam had advanced timing not retarded. I tend to look more at the line than the numbers. Anomalies are easier to spot that way. once you see the graph it sticks out like a sore thumb. Either way since i can correlate it to the other Rover i need to start checking all the other signals and sensors this weekend and compare them.
Thats the cheque we will see if the body can cash it

Yes we are seeing diminishing returns for more cost and complexity which is not really sustainable for the auto industry or consumers.

Carbies didn't always run that well in the old days either. But at least they ran, And yes fuel injection is a step up in economy, power and to some extent reliability. But we also give up a lot of simplicity that meant you could still use your vehicle when it wasn't quite right. And we could come up with more than one creative way of finding issues. Sometimes the solution was simply to turn the radio up louder. We didnt have have to deal with warnings and buzzers constantly flashing in you face while driving And most importantly a substantial failure didnt generally result in unscheduled engine disassembly. That usually required stupidity.
As for the VW i had a 73 Beetle. I had to pull the motor and change the transmission. That took all of 4 hours single handed, from park the car to drive it away. The hardest part was jacking the car up high enough to pull the engine out from under the bumper skirt.
Im still up for the challenge thats why in on here, but at 61 years old the mind is writing cheques that the body cant cash. My days of coming home from work and pulling an engine before bedtime are over. Thats now been relegated to weekends.

As i see it
"Intake variable camshaft timing bank 2" and "Intake variable camshaft timing, bank 1" I think are the actual cam position calculation from the crank and cam sensors. Readings fluctuate with engine speed 62.5-61 degrees. They are similar to each other and comparable to the readings of my good Rover Which ironically should mean that they system is actually working as it should

"Variable valve timing bank 2 output duty ratio" and "Variable valve timing bank 1 output duty ratio" is the PWM signal being sent sent to the solenoid actuators.

"Actual inlet variable valve timing position, bank 2" and "Actual inlet variable valve timing position, bank 1" are the result of a feedback error calculation target valve timing angle +- actual camshaft timing = Actual inlet variable valve timing position OR this may also be the timing adjustment command. it seems to be a calculated value for some part of the timing system, not directly reading a cam or crank sensor.

I cleared the codes and then collected this reading.
The latest graph
(https://drive.google.com/file/d/1h7YIBzQ4ozGM-mykPW4ZwvUXHeB8N462/view?usp=drive_link)
For comparison here is the same graph taken from the good Rover
(https://drive.google.com/file/d/1uu8KleuSBdLJXQyMiadj7cq0-FLidDDB/view?usp=drive_link)

As for the chains, I am very familiar with that video, My chains are very similar to his with respect to the tensioner length, So the should be ok, both are equal length and do not appear overly stretched. I have retimed the engine twice with better results each time. Before i opened it up the timing was similar to my good Rover at 60 and 65 degrees. The "grenade pin" comes in the timing kit, however a drill bit of similar size will also work. They are removed before tightening the sprockets and another tool is used to tension the chain and sprockets prior to and during the initial tightening sequence. Since my first attempt did not resolve the issue. I went in again and checked to make sure the sprocket in question was locked in place. Since i found nothing wrong with it I removed the chains and sprockets then reinstalled them on the opposing banks. If the chains or sprockets were at fault this should have resulted in the fault moving to bank 2. Sadly that was not the case. I then replaced the cam sensor with a new one from Rover hoping for a result as i dont own a scope. I took the crank sensor from my good rover and tried that as well. No luck However i did notice a change in the exhaust smell with that sensor and it went away after putting the original one back in.

To summarize Im certain this is not mechanical. The engine runs too smooth for a cam to be that far out of sync and/or from a faulty sprocket. A sensor can create a 0 input and the associated jump. I dont think its possible for a mechanical fault to cause a reading like that without sound or vibration evidence. This leaves me with another sensor that is faulty and should correlate with the jump. Or the ecu is faulty. Unfortunately swapping the ecu out is not an option,
Its times like this I really miss carburetors.

Lpgc wrote:

I forget how the supercharged Rangerover engines PCV systems are piped up, usually a PCV valve allows plenum vacuum to suck fumes out of the inside of the engine but not blow boost pressure into the inside of the engine.

Yes that is the way they are set up according to the manual.

Lpgc. I hoped you would jump in on this.
I did not think of the fuel trims and cats. I will check them. But since i cant drive it im limited there.

Lpgc wrote:

You're seeing readings for cam timing and other readings for actual cam timing. Might expect cam timing to be aimed for cam timing, actual cam timing to be cam timing readings. Similarly the ECU probably sends data via OBD for aimed for mixture (lambda equivalence) and actual mixture.

Yea I couldnt quite translate my thoughts properly there. The faulty reading is a calculation to verify commanded position vs actual position and something is screwing up that calculation. Unfortunately I cant see/read the commanded position and I dont know how the calculation is derived However from the "actual" readings which im assuming are taken from the camshaft sensor. Since there is no rough running farting or sputtering. And we can see that they are responding the same as bank 2. Which means the mechanical part of the system is working properly and properly timed as well
I did try the crankshaft sensor from my working Rover to no avail.
I will check all the other engine sensors to see if i can find a correlation somewhere.

New camshaft sensor installed, and the issue still persists. I have checked the wires from the cam sensor to the ecu. No issues there. Cam sensor ground is also good, since it grounds thru the ecu that means the ecu ground is good. At least that one, there are 4 of them that all go to the same ground point I will check the rest as well but i dont expect any issues there.
The "Actual inlet variable valve timing position", is less than 1/2 degree total on the good Rover for both banks. The faulty one reads the same on bank2 but bank 1 is 9+ degrees out. Since the "Intake variable camshaft timing" # are actually changing with engine RPM on both Rovers. This may mean that the "Intake variable camshaft timing" #s are the actual cam sensor readings. And i wonder if the "Actual inlet variable valve timing position" #s are a calculated # using the math of the crankshaft position for a feed back loop verification.
I will take the crankshaft sensor off my good Rover and try it on the faulty one.
Oil pressure not reaching the VVT sol maybe but if the above is true then it is not mechanical. Thats about all i have left before adding some ATF and snake oil to the engine oil in a hail mary hoping that this is the case.

Any thoughts on something i may have missed??? Besides a bullet or a stick of dynamite.
Im at a complete loss here.

I think you have to put the engine under various load conditions for a while for them to settle in. I had over an hours drive back after picking up and installing my new maf sensor before i checked. By then it looked a lot better.

OK here we go...
I went back into the timing chains. Chains were tight and no cam movement. Then I removed the chains and attempted to turn both phasers with the cams locked. Nothing moved. I found that bank 1 oil screen feeding the phaser appeared to be plugged with varnish. So i cleaned it and reinstalled it. Checked the solenoids with the battery for proper movement. They tested good. I then swapped all the sprockets and chains to the opposite bank. It started and ran great. After all that the fault remains. However after clearing the faults it only comes up once the throttle is depressed. I decided to start the graph recording before starting the engine and the one sensor seams to read 0 until the throttle is depressed. Then it goes immediately to 10 degrees out. Since i swapped everything and the fault did not move to bank 2 there should be no issue with the sprockets or timing. That leaves me with the cam sensor. Attached is the graph at startup.
I will be ordering a new sensor tomorrow.
Any input from the electrickery gurus would be appreciated.

https://drive.google.com/file/d/1TOKOxpFp7LCvX1xlXrsgpywwx0Vq9MWV/view?usp=sharing

Thanks Lpgc for that description! That helped me understand it even better than the first time.

I have 2 different Denso MAFs. The second one with all the numbers is the one purchased from Land Rover. The 602 came with my latest Rover purchase. No faults, but i have not driven if for more than 10 miles twice so i cant vouch for it
pics
https://drive.google.com/file/d/1-h9afo65nHN4TrMnQuhdKPfUD9UeJirE/view?usp=sharing
https://drive.google.com/file/d/1QiBm2ANPU_VkmL5mDR2RIXoV7j81edSh/view?usp=sharing

I will get a part # for you as soon as my wife comes back with it. I think you can get them at rock auto for a decent price
If your MAF sensors are old it might be a good idea to replace it anyway since the deteriorate over time. According to a lot of posts i have seen cleaning them is a short term solution. If memory serves the denso has the manufacture date printed on it with the part #.
Also did you smoke test your intake plenum and air filter housing? When i did mine i put a plastic sheet over the air filter and the put the cover back on. Smoke was added into the engine port at maf sensor. This could be a problem area.
It may be fuel pump related as well. Unfortunately because the pump is pwm controlled and pressure fluctuates, without knowing what the pressure and flow should be in relation to the pwm signal, there is no way to test this without throwing parts at it. (Which i hate but sometimes there are no other options.
The maf sensor seems to be a common problem associated with this code across all brands. So before replacing the fuel pump i would probably go to it first. AFTER you have eliminated any possible vacuum issues. Simply forgetting to plug the rocker cover into the intake plenum will also set set off the code.
Just a note on the brake booster. if it is bad i think it vents into the passenger compartment. So that may be something to double check.
On more thing, air filter; do not use the oil type air filters. They will contaminate and ruin the MAF sensor. I removed mine when i bought the truck but by then the MAF was already intermittently underreporting.

Ha... I hope you are not looking for me. Since i was on the receiving end of all that knowledge. But anyway, My issue was erratic, it would come and go. Sometimes without clearing faults. It turned out to be the MAF sensor. This is what tells the ecu how much air the engine is pulling in, The ecu then calculates the fuel to put in, and the O2 sensors check and force adjustments. If i understood all of that stuff correctly. One pair of fuel trims are sort of a baseline collected over time to allow for engine variables like injector flow rates etc. The other trims are used for "live" fuel calculations. (throttle, air press, engine temp) Im not sure which on is which. Together they are used by the ecu to determine how much fuel to add. But when they go out of the working window the ecu will set a rich or lean code. Obviously rich means too much fuel not enough air and lean is the opposite.
The tool i use is the IID tool I purchased online. The tool gives me the option save files as a PDF. I then just upload that to google drive and used the link in posts.
I ordered my MAF from Land Rover and they gave me the Denso sensor. So for starters i would put your Denso model in. The readings should follow the engine RPM.
The sensor voltages and numbers dont mean anything to me since i only have a basic understanding. I find the graphs much more helpful. But i can give you my 2 bits.

As for fuel pressure it is all over the place. If memory serves pressures were high 30's to low 70's. Graphs should still be in the thread, if not let me know. Depending on load, engine rpm and throttle. I was never able to find an actual pattern in it. What i did find however is, there is a switch in the fuel filter that stops the fuel gauge from reading. These are the two wires on the bottom of the filter. I assume that means the filter is plugged. But when this happens everyone seems to change the filter and the fuel pump as well. Which may or not be necessary.

Pcv valve? if i remember correctly It should only close if you blow into the engine side the rest of the time i is open. sucking or blowing on the intake side wont do it it should stay open. i think Its job is to remove fumes from the engine but to stop overpressure (major blow by) from going into the intake after the throttle body.

Any exhaust leaks before the O2 Sensors? I have small pinholes but they dont affect it. A large enough one will throw out the O2 sensors. I had to use my phone camera to get into there and take pics to actually find the pinholes.

Another question is are you in North America. If so do you have an EVAP fault. This will also cause the engine to go lean. Gas cap, evap line, purge valve etc. NA vehicles require an evap pressure test system. If not you will have to smoke test the evap system separately or try disconnecting and plugging the evap line. You may be able to do this at the purge valve.

Vacuum booster. I dont suggest plugging this one and driving on public roads. These things are extremely hard to stop with no power. Thats why there is a electric vacuum pump if the engine shuts down. But maybe smoke test it separately.

Longwinded and a little unnecessary but I Hope this helps.

Oh Yea. I forgot they changed to vortec engines in the 90s. So yea ZDDP is not needed