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1970-1995 Range Rover Classic
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23 Posts
Discussion Starter #1
Hello everyone

Ive been on here reading post after post about lean codes and what others have done and found, and watch videos on fuel trims and reading discussion on them... so much that i think ive become more confused.

So lets start from the top. I own a 2006 RR HSE. It has 109k miles on it, it runs great(i think). But has the notorious P0171 and P0174 lean bank 1 and 2 codes that come back within 40-50 miles after clearing them.

I bought it with these codes knowing it was fixable and the price was right... it think.

Ive done a full tune up - plugs, oil, filters, fuel filter, ran injector cleaner thru the system multiple times(ive put over 1500miles on it since i bought it)

I flushed the fuel system all the way back to the filter. Pulled the fuel rail and cleaned each injector with a home made injector cleaner.(9v battery and carb cleaner)

New delphi MAF, and ive tried finding a vacuum leak every way possible except a smoke test.

My code reader can pull live data so heres what my freeze frame showed when the P0171 code was thrown

FREEZE FRAME
engine temp- 197*
STFT B1 0.0%
LTFT B1 6.3%
STFT B2 3.1%
LTFT B2 6.3%
Intake manifold absolute pressure- 20.4 inhg
RPM- 1472
air intake temp- 37*
MAF airflow rate - 3.3lb/min
barometric pressure - 30.6inhg
absolute load value - 39.2%

After a 200 mile trip(with the CEL light on) my fuel trims at idle in my drive way read
731rpms

STFT B1 -5.5%
LTFT B1 9.4%
STFT B2 -3.1%
LTFT B2 7.1%

2300rpms

STFT B1 1.6%
LTFT B1 9.4%
STFT B2 2.3%
LTFT B2 7.0%

So basically i dont know what to do with this info... From what ive read my fuel trims arent that far off(i believe anything within around 10% is acceptable??)

Also i dont know if its had a software update yet.... but i was hoping to diagnose the issue before spending $230 for and update that it may or may not have had yet.

Any information that ive left out please let me know, or info from my live data that i should look at? The 02 sensors show that they are working, also had a mechanic(not a range rover mechanic) look at the data and he didnt seem to find anything out of the ordinary.....

Jason
 

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1970-1995 Range Rover Classic
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23 Posts
Discussion Starter #2
Also i forgot to mention i removed the throttle body and cleaned and applied some gasket maker to both sides of the metal gasket, just incase it was leaking.

I havnt replaced the intake manifold gaskets yet... i was hoping to understand the data from my scan tool before throwing more parts at it.
 

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2006-2009 Range Rover MkIII / L322
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532 Posts
Its sometimes very good to have both codes.
In my opinion you have a small leak.
I am a 4.2sc guy buy little know your engine from friends.

You did a good job to clean injectors but if the codes were injector related you had misfires.
Both banks are effected we can ignore a crack or a hole on exhaust pipe. Its a very little chance to crack on both sides
I didn’t see your fuel pressure.
Fuel pressure sensor have to be checked if you have a little black smoke from exhaust.
Ehat about fuel consumption?
In this sitiuation i think you have a leak after maf sensor.
O2 sensor feels unmeteres air leans the mix. I am not professional auto mechanic just doing brain storm.
We can also eleminate bad fuel situations because you had this codes a while
Than 2 more things can effect bith banks. Pcv and egr
I dont have egr valve on my 4.2 engine but it can be leak from gaskets.
You have 2 pcv hoses for each bank and one valve. You can replace it easily and check the hoses.


And I suggest you to check this gaskets

Just talked about this with my friend who has a 4.4 engine he supports.
On this engines very hard to identify the leaks buy you have to do a smoke test
 

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1970-1995 Range Rover Classic
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23 Posts
Discussion Starter #5
Thank you for your reply!

I new I was leaving info out. I did replace the PCV and fuel pressure is good. I checked it on my fuel pressure tester (74psi before the fuel rail) and on my ob2 reader it also read 74psi

MPGs- driving to work(100 miles round trip) and on the highway ive been averaging about 17.4mpg according to the mpg consumption, i have done a hand calculated test yet since my fill ups havent been consistent full fill ups. Ill be filling up today tho and get a proper mpg calculation.

I havnt replaced the EGR gaskets, Ive soaked every hose and vacuum connection with starting fluid and carb clean and even sprayed the EGR down real good but never heard the idle change so I kind of ruled out the EGR gaskets... but ill definitely look at it again and probably order some gaskets.

I was hoping someone could chime in on the fuel trims and give me a bit more insight or an opinion on them? Do they look off? normal?

thanks
 

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2006-2009 Range Rover MkIII / L322
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532 Posts
You have a very good milage almost 8lt. For 100km. I can’t even imagine this mpg.
But i think you have a high fuel pressure its almost 5bar if i converted right. If the engine is running 2.5-3bar is normal if the key is on second position 5bar is norm mine shows almot 5.

I dont know this video works or not but this is very very healty range rover from russia, owner is from another forum and his engine works even better than a new engine you can see the trims and mafs readings

Range rover06 trims

With that milage if you are leaking somewhere its very tiny must be. If you have sdd maybe you can try update pcm.
 

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1970-1995 Range Rover Classic
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23 Posts
Discussion Starter #7
My fuel pressure was taken with the truck idling and I've observed it while driving too. Always above 67psi according too my scanner.

With my fuel trims being only a little out of whack I'm starting to think more about getting the update.

Anyone else have any ideas or input?

Thankyou
 

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1970-1995 Range Rover Classic
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23 Posts
Discussion Starter #8
Anyone? I know this issue is like beating a dead horse.... Ive read so many posts with this issue. But my issue seems different

Im trying to diagnose it before spending more money on guesses...
-$220 for the software update
-$200 for land rover dealer to do a smoke test
-$200 on new intake gaskets( unless someone has found a cheaper source than i have?)
-$$$ on new vacuum lines, breather hoses ect ect
Or just paying an indy mech. $200+ to diagnose it



Thanks in advance!

Jason
 

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Registered
2006-2009 Range Rover MkIII / L322
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532 Posts
Anyone? I know this issue is like beating a dead horse.... Ive read so many posts with this issue. But my issue seems different

Im trying to diagnose it before spending more money on guesses...
-$220 for the software update
-$200 for land rover dealer to do a smoke test
-$200 on new intake gaskets( unless someone has found a cheaper source than i have?)
-$$$ on new vacuum lines, breather hoses ect ect
Or just paying an indy mech. $200+ to diagnose it



Thanks in advance!

Jason
If you are planning to keep this car for a while you can buy a mongoose cable from aliexpress and download jlr diagnostics software from inet.

With this cable you can update your pcm and diagnose the faults you have.
Just dont update tcm!!!

Leaks are very difficult to find on this engine, its a good challenge
 

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1970-1995 Range Rover Classic
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Discussion Starter #10
Mylife1903 thankyou for all your help, I'm not quite sure how long I'll be keeping this RR yet, especially if I have to spend hundreds more to just get it to pass smog. I'm not against the software you suggested, just depends on how long I plan to keep it.

I love range rovers, always had a thing for them, but so far everyone I've had has ended up costing me so much money and time that I ended up selling it cause I could justify the money for something I didnt need and I always had other projects going on.

I'm going to replace the intake gaskets first, since that's cheaper than the software update. I found a gasket kit for $110 and it includes the egr gasket too.

Thanks

And if anyone else wants throw some ideas out there or suggestions dont be shy!!

Jason
 

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1970-1995 Range Rover Classic
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Discussion Starter #11
On a side note, I did the transmission filter and fluid the other night. Used the separate filter and metal pan kit from Atlantic British. The old fluid was brown so I knew it was due.

After removing the transmission pan which was very simple, I noticed the inside of the pan had a date stamped on it, July 2016 so I know that this rig atleast has had one transmission fluid and filter change in the last 110,000 miles.
 

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1970-1995 Range Rover Classic
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Discussion Starter #12
A little update, I pulled the intake and everything attached, cleaned and resealed with my favorite gasket maker to ensure ZERO leaks possible!! all new injector o-rings too.
Cleared the lean codes and drove it. And once again the lean codes came back after 50 miles.

When i look at the freeze frame data the rpms are always under 1800rpms, mph is less than 50mph, STFT are between 0-2% and LTFT are around 7-8%, down stream o2 sensors always reading between 0.7-0.9V

So the other day I decided what the heck ill put a new o ring on the oil dipstick(it felt snug... but not tight) and put a thick grease around the gas cap oring to help seal it since I noticed the gas cap o ring was dry and cracked and didnt have a new oring on hand.

After that i was able to go 200miles before the same lean codes came back on again! I thought i had it fixed but was waiting for my evap system monitor to show it was ready before I went to smog it. I just installed the new gas cap o-ring and have yet to drive it very far yet but im hoping it solves the issue.... Im thinking the grease on the gas cap helped to seal the system but only for a short time and then the seal leaked and threw the lean code??

Anyone have any ideas... suggestions? It seams like getting a better seal on the gas cap should help... or fix the issue. Would the gas cap not sealing cause lean codes?

Thanks
 

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1970-1995 Range Rover Classic
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Discussion Starter #13
Update on my situation, I still keep having the lean bank 1 and 2 codes and freeze frame data is always the same. Low speed and under 1800rpms, engine up to temp and long term fuel trims between +7 and +8%.

I finally got my hands on a smoke machine and smoked it like it was a tasty rack of ribs!!.... but nothing.... no leaks anywhere!!

Last thing to do is take it to land rover and have them update my fuel trims i guess??

I was told by a the land rover service center that they wont be able to tell if ive had the update done already... does that sound right? It seems to me that the system would have a different code or number in the ECM showing it has the newest update...??

I hate to throw $240 at it if it doesnt need the update...

Jason
 

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2006-2009 Range Rover MkIII / L322
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532 Posts
No leaks, no misfires(plugs coils injectors are eleminated)
Maybe o2(very rare both are failed) maybe exhaust manifold
I am out of idea
 

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2006-2009 Range Rover MkIII / L322
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Have you cleaned the throttle body, not just with a cleaner, but with the cleaner and a soft cloth and toothbrush on both sides of the throttle blade? I also replaced my MAF with a new one (Toyota makes the exact same MAF for about 20 bucks) when I had these codes, don't know if it helped or not, as it took about a month and a half for the codes to disappear. Mine eventually turned out to be my PCV valve, or at least that was the last thing I replaced and the fuel trims returned close enough to normal for the codes to go away. Mine is an 06 HSE also.
 

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1970-1995 Range Rover Classic
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Discussion Starter #16
No leaks, no misfires... not even a little stumble.

New MAF(Delphi)
I removed the entire intake manifold and everything attached to it and cleaned and resealed and reinstalled. Throttle body was cleaned very thoroughly also.

New PCV, new spark plugs, new oil and filter, new air filter, new MAF, new fuel filter....

The entire fuel system was flushed and all injectors removed and cleaned and inspected.... all new injector o-rings I installed too
 

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1970-1995 Range Rover Classic
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Discussion Starter #17
On my scanner while reading live data from the engine, I see my down stream 02 sensors are always in the 0.7-0.8v range at idle... but all my other vehicles read 0.45-0.47v at idle. The voltage does change when revving the motor so I know they aren't dead.

The vehicle runs great, I average 17mpg commuting to work and home.

I've looked for exhaust leaks, and I know what they sound like.... but I cant see anything or hear anything out of the norm.
 

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1970-1995 Range Rover Classic
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Discussion Starter #19
Is there a fuel pressure sensor on 4.4 engine?
Did you check your egr gaskets?
Yes there is, the fuel pressure is 70psi at idle and even under load it doesnt drop below 60psi. I removed the whole fuel injection system and cleaned and replaced all o rings, flushed the fuel lines from the fuel rail to the fuel pump and then installed a new fuel filter.

Egr was removed, cleaned and resealed...

Also reading my data stream at idle, my wide band 02 sensors are reading bank 1- 0.0 ma and bank 2- 0.8 ma

This would indicate a rich condition if I'm understanding these readouts correctly.

1.0ma is perfect air fuel ratio, anything above 1.0 would indicate a lean mixture and anything below 1.0ma would indicate a rich condition.

Someone chime in if ive misunderstood this please.

Jason
 

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1970-1995 Range Rover Classic
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Discussion Starter #20
Also my bank 1 and bank 2 equivalence ratio(lamba) sensors are reading 0.991... which means it's running a smidge on the rich side....

This is all confusing for me, given my lean codes and the data stream reading on the rich side on all my monitors...

I would love to understand all this more, if anyone has a more input, I've seen how big of an issue this has been and I'd like to fix my rover along with passing on this information to anyone else that's having just as hard a time figuring out the lean code issue and hopefully saving them alot $$$ at a dealership or indy shop.

Jason
 
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