So i have a Range Rover Sport with the above engine and am pretty much out of ideas as to why it's throwing lean codes. This engine does/did run lpg so heres whats been done.

1. Both heads rebuilt with hardened valve seats since we though the valve seats were knackered
2. Software updates
3. O2 sensors changed, both pre and post cat
4. MAF sensors changed, with decent one
5. Plugs changed, ngk
6. Coils changed
7. Adaptations cleared 100s of times
8. Injector cleaner used
9. Fuel pump and filter replaced, dropped the tank but was worth it
10. Smoke tests so many times but all seems air tight
11. Replaced valve cover gaskets to make sure it was air tight

Still both banks lean codes. the class P0171 and P0174. Am currently trying to avoid getting to the injectors to check them since the supercharger will have to come off and knowing me I'll change the pulley while its off :P But am completely out of ideas and any help would be appreciated

Cheers
Martin

 

Definitely you have a leak and its affecting both banks pretty much equally.Using SDD, pull up the STFT's, the Bank 1 and 2 Sensor 1currents and the Bank 1 and 2 Sensor 2 voltages using the the SDD monitoring program and make sure the currents nd voltages are wiggling up and down. the currents on sensor 1 should be flipping just above and below 0 and around 50uA for a good system and the sensor 2 voltages should wiggle just above 09 v to around 1v max.Make sure the upstream sensors look similar and wiggle ar close to each other basically look for differences. If they are outside these ranges or different side to side that helps narrow in on where the leak is. I would then go in and replace EVERY O-RING on EVERY Vacuum line and PCV line. Do the dip stick o ring and the oil filler cap o ring too. Just do it and eliminate potential leaks there. ALL of mine were leaking a tiny bit. Go for a few drives and see how it feels. A couple on drive cycles.

Then open up SDD again and monitor the same signals as before . I narrowed the limits on my signals to get better resolution so you might want to change the default plot limits as well. Set the high and low limit so the wiggle is shown at its max and min levels. Then with an observer watching the sensor 1 currents, and/or the STFT's spray small amounts of carb cleaner at various o-rings or injectors or egr or intake tube rubber fittings and hose clamps and watch for any changes to the trims or the signal levels. when you hit the leak you'l see it but it might be very small so thats why good resolution is needed.

I'll post pics of my system AFTER i founds and fixed my multiple leaks so you can compare
T

 

I’m posting this from my phone so it’s really hard to see small thumbnails but hopefully I’ll grab the right screenshots today was talking about earlier

 

More from a good system

Narrowed the ranges here

 

I don't think he can use SDD as it's a Range Rover not a Jaguar...

 

he posted the fuel trim page from SDD in his post! And I believe SDD does do RR as theres a RR icon at the top of the SDD screen

 

Oh, OK - news to me. Thanks.

 

ill give it a gander. I also have a GAP IID Tool which allows me to access the values if required. The IDS is only handy for the Adaptive Fuel Trims.

Also a weird one, when cruising on a motorway at 70ish for a while I get the knock sensor for bank 1 going off and catalyst efficiency codes for both banks. Not sure if related but yah.

Thanks for the replies

 

sounds like a vacuum leak on that bank causing a lean condition and detonation

 

What version SDD do you run? Im not sure of all the stuff SDD does for Range rovers but I would think its the same as for jags but who knows.

When in SDD, go to the DIAGNOSTICS tab, and the Selected Symptoms. Then go to Engine or drivetrain and start selecting conditions loss of performance or rough idle and other engine running poor conditions. Then check the codes and then do to recommendations to select the Datalogger and pick the same engine parameters shown in my screen shots and run some datalogs at idle after its warmed up If you can run the datalogger that is

 

and STOP clearing adaptations. Sometimes it takes a while for the engine to adjust to present conditions. It will start adjust the long term fuel trims to make needed corrections and you want those to stay. after a while it might settle down but I bet you have a vacuum leak and the LTFTs will be high

 

Why wouldnt it happen on normal driving though?

Am not sure tbh, my problem is most the time there isn't the codes. A missing piece of the puzzle is the car was using a shitty chinese MAF. Because of that I got codes, when I swapped it for an original Denso MAF, I just get high fuel trims. Maybe a random code but never as before.

I only clear because I try to do random **** with lpg which messes with the fuel trims.

 

codes are only set when a bunch of specific symptoms occur on two consecutive drive cycles. And for fuel trims to be set, the trims have to exceed a specific number like 20% i believe. If the trims dont cross that threshold, on two consecutive drive CYCLES (not drives), you wont see a code.

The chinese maf probably ****ed up your fuel mixtures so over time, the long term fuel trim got set to bring the trims in line with its desired levels. Then you changed it and got the maf that accurately measured the airflow so the it started to correct for the previously set values. And those trims were probably pretty high so codes were thrown. Then you cleared the codes and reset the fuel ytims and when it tried to correct for it it set the code again and you cleared them again

STOP DOING THAT

Run the car for a week or two and ley things settle out. The light will reset itself if there are no leaks. Then you look at the trims at idle to see what they look like.

STOP RESETTING THINGS. It doesnt fix things. You need to fix the problem first

 

am not resetting the fuel trims for the fun of it same with the codes. am making a change like replacing maf or fuel filter/pump and then clearing the adaptive fuel trims because am sure thats what the manual says.

in terms of orings, will any orings do or do they have to be specific JLR orings?

also it defo seems worse on bank 1. so ill start with the pcv system. first thing i replaced when i got the car was the pcv so ill start on those pipes.

 

PCV will affect both banks both vacuum line goes to the elbow between the throttle body and supercharger.

a leak in one sides Intake manifold gaskets, exhaust connections, fuel injectors, blower output connections or EGR will affect only one bank. Even though the pcv valve is onlt on one valve cover the end of the hose goes to a common place that feeds both banks

I used various sized orings from a few oring kits I bought that has almost every diameter and thickness known to man. just make sure they are compatible with fuel or oil so they dont melt

 

sure but couldnt it affect one bank more than the other? i mean bank 1 is slightly worse than bank 2 according to the adaptive fuel trims above. but both pretty bad.

 

I must’ve had at least a dozen different vacuum leaks on my engine when I got my car. From the PCV line to the air intake that goes to the driver side valve cover for the air intake at the throttlebody connection fuel injector and intake manifold gaskets and exhaust pipe and the vacuum Line fitting that goes to the brake booster.

After i fixed all the major leaks that threw the lean bank 1 and lean bank 2 codes, i started seeing random cat efficiency codes for only bank 1. So i looked at the o2 sensor outputs.

The leaks that would affect both banks did show a slight different side to side but they were both hi. The vacuum leaks that only affected one bank like the fuel injector and the intake manifold gasket showed great on the side that didn’t leak and just a little bit high on the one that did leak because it was a very small leak. my long term fuel trims on the good side were down around one 0 to 1. But on the leaky side it was around 4 to 5 possibly 10 but it must have gone over 20 every couple of weeks (bc the MIL came on) every couple of weeks and then would clear itself. So when I had the leak on only one side (bank 1) both banks looked pretty darn close (i was monitoring sensor1 current) but you could tell the bad side was offset from the bank 2 o2 sensor current on the datalogger graph it was clos to the zero.

When it gave me a p0420 code. The signal are top to bottom: bank 1 sensor 1 current Bank 2 sensor 1 current Bank 1 sensor 2 voltage Bank 2 sensor 2 voltage

After I fixed it

After I fixed it

 

And heres why the codes didnt come back for several weeks. Because it needs to meet all these conditions to set the code

 

some good info

 

i think am just going to get fresh PCV lines.

that catalyst code explanation is very interesting because I do only get them on motorway. it would explain why they never cause a MIL as well. because i need to clear them mid drive otherwise the timing is retarded too much and I lose power