Pics of plugs and screen shots of graphs
https://drive.google.com/file/d/12vur0ivo8lhXn0c6hyKH5j7G6LlAXRBf/view?usp=sharing,
https://drive.google.com/file/d/17voBsMMhXqLc6RWwUe0hb-i5l8-AMKXH/view?usp=sharing,
https://drive.google.com/file/d/1G_HRQ4vDfymGCqrkPVfFzuoEKrIRZAaQ/view?usp=sharing,
https://drive.google.com/file/d/1LhFXtSvUStQkqvU7Iqz7iKige1gGs7mI/view?usp=sharing,
https://drive.google.com/file/d/1NbnaY0lbP46FoRRH4eDWI1qn872wD26e/view?usp=sharing,
https://drive.google.com/file/d/1S80jgIWHYvhU5ssMYFU1DqxIDqCmEGwX/view?usp=sharing,
https://drive.google.com/file/d/1ZnNrEy2ISnLoboGpWORiS7NC7qx72xSp/view?usp=sharing,
https://drive.google.com/file/d/1d6yAN3DC9WQke74zdR1ZDfesaHiJvp-k/view?usp=sharing,
https://drive.google.com/file/d/1x0c2KurkpUEf4sM8fbrPHnOsXZQ4XTbD/view?usp=sharing,
https://drive.google.com/file/d/1yTPC1blnS8QizmFO-pPlBS7h6nxiLf8R/view?usp=sharing)
Let me know if this doesnt work
So I revisited the smoke test today. I used the same method as described earlier. Apparently my memory is not that accurate, Using that method does check the crank case but does not check the brake booster or the vacuum pump due to check valves. However if you put the smoke into the brake booster line instead you get the same results and it is easier to seal with the correct size hose.
My results were the same as the last test. The was no smoke from the exhaust, meaning no intake and exhaust valves open in the same cylinder. No vacuum leaks showed up. I did pulled the dipstick and open the oil fill cap to make sure I had smoke in the crankcase. I tested the booster and vacuum pump separately. I pulled the hose going to the fuel pressure sender which comes from the boost side of the supercharger. I found absolutely no vacuum leaks. I did find the rubber adapter used on the fuel pressure sender between the hose and sender, was somewhat soft and spongy. It did not show any leaks though. I installed two zip ties on this adapter as a precaution.
Interestingly enough though, I did discover that at roughly 5 psi the air filter housing stretches enough to let the smoke out where the halves meet. LOL
I then took it for a quick drive to warm it up and get a drive cycle before replacing the spark plugs. Here is where the fun really starts.
When I removed the plugs the three plugs that looked lean a few week ago, they are now quite a bit better. They were not perfect but most certainly not clean and white.
Im beginning to think that this actually could be related to something else like outside temp being at or below freezing causing shrinkage. Or maybe just poor gasoline.
I could be trying to figure this out in the cold weather this fall. (yah...NOT)
All I can do at this point is keep occasionally logging data to catch something, and/or wait for whatever causes the code to consistently show up again.
Ive got to say Im stunned with the response I have received on this issue. Especially since this is not a P38 or older model rover. Hats of every one that put in their 2 cents regardless if it helps or not. I am certainly not done with this but I will not throw parts at it in hopes of this going away. Unfortunately it looks like this is going to take a while.
Im still trying to make pics available, Imagur does not seem to like me for some reason
If anyone has any thoughts on something Ive missed, Im all ears
I will keep you all posted if I find something
Karlos01
Im batting zero at this point, All i can say start at the beginning. Vacuum leaks first, then try unloading a can of WD 40 all over the motor when it is idling, Listen for changes in rpm while doing this, Then start logging data on all the stuff in this thread, fuel pressures, lambda and look for abnormal reading or patterns. Its cheap enough you could try some injector cleaner. Maybe log fuel pressure before and after cleaner. The problem we both have is that we dont know what the normal readings and patterns should be. In my case since I only get one code, I can reference the other bank,
Sorry Im not much help.
The smoke test was done over winter inside my shop. I placed a screwdriver in the throttle body to make sure it was open, But i did not turn over the engine, I plan on redoing the smoke test tomorrow to see if i missed something, I can check the what the o2 voltages are tomorrow. I also have new plutgs to put in it. I doubt they are the issue as there are no misfires registered, I just dont know how old they are. Im considering swapping the post cat o2 sensors to the other side to see if any readings change.
Gilbertd You mentioned maf sensor logging, I have occasionally looked at the maf, It did increase and decrease with engine speed . From what i have read they generally work or dont, If you have to clean it to clear a code then its time to replace it. Am i wrong on this or is there something specific to look for? ie spike or dropout I did clean it last year when i got the truck and have specifically not cleaned it since.
Yea i wondered that too but exhaust and intake on the same cyl have to be open. Since there is only a few degrees of valve overlap in 720 degrees I think that is possible.
Also i think there are some check valves in some of the vacuum lines that would prevent smoke from getting to certain areas ie the vacuum pump and the booster itself.
I think i goofed while doing my homework, I havent dealt with this stuff in so many years Ive forgotten a lot.
So I guess i get to do it again.
Sorry I have been busy logging data and dealing with glitches on my IID gap tool. I have been logging and correlating lambdas and fuel trim, o2 and lambda, fuel pressure and injector pulse width, etc.
I live rural. Its 10 min to the first stop, turn , or town in any direction, So I spend most of my time at cruise 100-110 kmh. I only go thru town on my way home and it has 3 stop lights and a timmies (coffee shop for non Canadians). 5 cars in a row is considered heavy traffic.
The mil code takes days to show up after the adaptive values are reset to zero. The p0171 lean bank1 is the only code I have. There are no other fault codes for the engine. When it does show up it is usually shortly after restarting once the truck is up to temp. I dont recall it ever showing up at cruise speed. It always seems to be 1-3 min after a restart. And oddly enough during cold weather. Last week it warmed up quickly to 27'C No code all week. Sunday night it dropped to 1'C, and we have been 5-7'C since. Tues aft on my way home thru town. Stop for coffee mil comes on about 2-3min after restart. (Last summer no code, Fall single digit weather mil every 3 or 4 start. Related? Probably not just hilarious.) I reset the mil but I dont remember if I cleared the adaptive values
Logging lambdas, very even only changes with throttle and load. Range 0.88 to 1.1 at extremes 0.88 under fairly hard accel and 1.1 on a downhill decel? Mostly .95 to 1.04
Kind of what we expect
Logging O2 sensors Bank1 reads about 0.5V higher than bank2 on both sensors, Bank1 pattern is saw tooth and bank2 is more of a wave. Other than pattern the trends are the same. Lambdas seem to follow this but slower wave motion
Logging fuel pressure and injector 1 & 2 pulse width Fuel pressure lags injector pulse changes (response time?) but does increase with longer pulse width and drops with shorter pulse width. At cruise a bit of a saw tooth pattern fluctuating about 5psi with the occasional larger fluctuation, Seems to change with load and throttle as it should.
Logging Fuel Trims they generally follow the same trends but there is a difference at cruise. The difference grows larger at higher RPMs but seems to return to very similar values at idle.
Im thinking I need to revisit the smoke test. My method. I placed a sheet of plastic film over the air filter in the breather and then put the cover back on. Smoke line was inserted into the intake breather via the rocker cover inlet. I had 15 psi on the smoke system and nothing came out. But this does not check the crankcase since the pressure thru the intake closes the pcv valve. I should have had smoke pouring out of the rocker cover inlet but there was none. There was also none coming out of the exhaust, I must have stuck it lucky and had no exhaust valves open. Or did i get something wrong?
More info found in the manual
Since this is a North American vehicle it has a DTML pump on the evap system. It checks the evap system from the fuel tank to the purge valve. Any leak in that system would set off an evap code before/with a lean code.
I have 3 options
commanded equivalence ratio
equivalence ratio (lambda), bank 1 sensor 1 (wide range oxygen sensor)
equivalence ratio (lambda), bank 2 sensor 1 (wide range oxygen sensor)
lambda bank 1
lambda bank 2
I have graphed all of these for a 4 min period at cruise
nothing below .988 or above .1.002 unless accelerating or decelerating
nothing jumps out as out of spec or serously delayed, nice sawtooth patterns, some variation in length probably due to load
What name or letters would i look for that are the mixture readings in the ECU?
It appears you did not finish.
I am using a IID scan tool. There is enough stuff in this tool to get me into trouble. (I Cleared the trans adaptive values, took the better part of 2 months for the trany to relearn :-) )
Does resting the adaptive values reset the trims? I did that 2 weeks ago.
The lambda's are hovering around the 1.00 mark. I will pay more attention to them tomorrow?
I dont usually let it idle before driving unless trying to figure this out which is mostly after/during a drive cycle. The code takes usually takes 3-5 drive cycles to show up and there are no other codes to go with it.
I know its still not right since the plugs and fuel trims tell the story I havent seen it for a few weeks since adding injector cleaner.
It could be a coincidence, I added the injector cleaner then the weather warmed up both times. Last fall as it got cold the code retuned every few days until it was parked for winter. I used it twice on nicer days over winter and just cleared the codes until now, since now I am driving it daily again I can hopefully sort this.
Ha, now this is bizarre. Its a good thing i have lots of hair to pull out.
My scan tool gives me a fuel pressure reading of 40 to 60 psi depending on how much lead my right foot contains. The unit I borrowed reads 10 psi less. Im not sure this means anything yet until i get an actual gauge on it.
Apparently my o2 sensors do not flip between 0 and 1 volt. They provide a constant variable readout between 0 and 1 volt, usually around 0.6-0.7 volts. Regardless both sides have very similar readings for upstream and downstream sensors. However the long term fuel trims are quite different. At idle they are quite similar but few decimals apart. But at 60mph cruise bank 1 reads 13.3% at 60mph cruise and bank 2 reads 8.8%.
I did read on another forum that plugs/coils or a bad cat could cause this. For all the work it takes, I might just swap the white plugs and coils to the other side and see if the fuel trim moves with them.
I was able to graph these and compare both banks, they stayed quite similar other than the fuel trims separating as I accelerate to cruise speed. Comparing cyl 1 and cyl 8 this also shows up in the injector timing with bank 1 having a longer firing time than Bank 2 as the speed increases.
Can I upload pics or do they have to be in some sort of online cloud thing?
You guys know all the links! I havent found that one yet. I did look into the pcv valve. I removed it the diaphragm does move with suction. There is a small vent hole in the top that allows the diaphragm to move, tested that with wd 40 while running and nothing changed. Since it enters the manifold before the supercharger it should set off bank1 and bank2 codes. That's why I pulled the plugs to see if it was actually an issue or some stupid tiny vacuum leak somewhere affecting all 8 cyl. Since it seems to be only 3 cyl that would point to a local vacuum leak at the intake but it passed the wd40 sniff test.
I have borrowed a cheap obd2 reader that has the o2 readings, fuel trim readings, and lambda readings.
Thanks for the info on the o2 sensors. That was going to be one of my next questions. Can someone explain what the lambda is and what to look for. I have heard this term and it appears that i misunderstood it thinking it was another name for o2 sensors.
The plugs are iridium type. I had planned on changing them after i figure this out. I should have other ignition faults if they are the cause of the issue.
I need to get some new tools. My 1980s compression guage no longer holds pressure. And my IID scan tool does not give me all o2 sensors.
I will have to check the manual again, I thought bank1 was on the RH side from the drivers seat. It is also the furthest forward closest to the rad. Unfortunately the manual does not help with diagnostics only how to replace parts.
I dont think im going to get to far this weekend if my tools are no good.
Ok here goes
Leolito, No idea how old the plugs are, They dont look bad, no misfires or codes other than system lean bank1 (right side i think) which is where the white plugs are located. I can post a pic when i figure out how. I have o2 sensor reading for bank 1 only for some reason, not sure about voltage. It reads 96% for the first 20km or so then goes up to 98%. Interestingly though during accel or decell it does not read. Not sure if this helps will look into this more.
Gilbertd, 1 maf sensor right at the air filter, i think 4 o2 sensors (I think this is what you mean by lambda) before and after catalytic each side. More research to be done on this. Ditto on the fuel pressure. Im leaning toward poor/plugged injectors.
mad-as. Fuel pressure is controlled by ecu via a pwm signal, According to the manual it should fluctuate but be a relatively steady 45psi at idle.
Aragorn I need to get a pressure gauge and figure out where it gets hooked up. The injector rail is buried under the intercooler's. I am currently reading pressure from the scan tool, thats why i pulled the plugs. It is a returnless system.I believe the pressure regulator is vacuum referenced since there is a vacuum line running to the intake prior to the supercharger. The absolute pressure reading is approx 5-6psi at idle. I think this is a vacuum since with the engine off it reads 14.5(1bar) Fuel Pressure at hard acceleration is 50- 60psi (3.25-4bar?) Engine is a 4.2L supercharged Jaguar.
I did unload a whole can of WD40 all over the top of the engine looking for vacuum leaks and none were found. I will do a bit more this weekend with vacuum and hopefully a pressure gauge. For right now I have put 3 cans of fuel injector cleaner into the fuel, cleared the engine adaptive values and have not had the code return. Although I believe this is a temporary fix. I will pull the plugs again this weekend to see if there is a change. I expect the code will return at some point in the next few months. I am currently leaning towards poor/plugged injectors. Opinions and suggestions are welcome since I do not want to turn this into a parts cannon.
Sorry guys I have forgotten to check this forum after i realized I posted in the P38 section. Since I cant find an L322 section I assumed this forum was dedicated to P38. I will catch up tonight after work.
I currently am trying to find the cause of system too lean codes. PO0171 and PO0174
A little history
Purchased last year around April PO171 code showed up almost immediately. Cleaned Maf sensor, and put injector cleaner into fuel. That seamed to clear the code until September. Then the code started showing back up intermittently. Stored the truck until spring. Smoke tested intake over winter and found no leaks. When i started driving the truck a week ago both engine lean codes came back. Added injector cleaner to fuel that cleared the bank 2 (P0174) code but the bank 1 (P0171) comes back. There are no other engine codes shown. I started watching some live values while driving the fuel pressure fluctuates a bit at idle and while cruising at 2000 RPM. It falls to 41psi at times. and then quickly recovers. It does increase to about 55-60 psi under harder acceleration.
Today I removed the spark plugs and the front three spark plugs of bank1 (right side not sure what the cyl numbering is) are white compared to the rest which are a nice light brown.
Im trying to determine if the injectors are partly plugged or the fuel pump is possibly getting weak. It does not run rough or stumble when driving.
Scan tool is a IID tool
2008 Range Rover Supercharged Canadian vehicle