I continue to strugle to find the issue and solution to this codes :

P0172 system too rich bank 1
P0175 system too rich bank 2 I m NOT LONGER getting any misfire codes ! which I m glad !!

have replaced new units : MAF sensor , new EVAP purge valve . new bank 1 o2 sensors (upstream & downstream) - NOT bank 2
tried a used throtle body unit from EBay not much help

I continue to get 381 to 384 kpa at FUELRAIL PRESSURE ...
these are some of the values I got the last time i used the icarsoft i930 scanner :

calculate loas value 32.2 %
engine coolant temperature 79c
STFT BANK 1 -22.7%
LTFT BANK 1 -20.3%
STFT BANK 2 -6.3%
LTFT BANK 2 -20.3%
INTAKE AIR TEMP 38C
AIR FLOW RATE MASS AIR FLOW SENSOR 8.02 G/S
ABSOLUTE THROTLE POSITION 3.5%
EQUIVALENT RATIO(LAMBDA) B2-S-0.942
OXYGEN SENSOR CURRENT (B2-S1) -0.05 ma
.... and few more values .. everything taken at idle speed.. I have read at another thread somebody ended up replacing to a NEW THROTLE BODY UNIT ! should i consider that ??

please help me understand these values or explain them to me ..should i just should I try to tap into the fuel line to mechanicly get a fuel pressure reading ? as kr9868 suggested a while back ?

im even considering putting back the old 02 sensors on bank 1 ???

 

Hang on there. The throttle body is just the air flow mechanism. The mixture is set using the o2 sensors. Stop throwing parts at it. You need to get the short term fuel trims up on a screen in real time with engine running for both sensors on both banks. You need to watch what they do over time. I took some video of my correct trims so ill try and post them. But the idea is with a correct fuel map, both o2 sensors should bounce around 0v. Like these

 

Your codes say too rich and the stfts are -20 or so. It think it sees a rich mixture so its shortening the fuel injector pulses. But is it one cylinder or all?

is a spark plug coated and not firing? Check the plugs and see if they all look the same. If not replace the black ones and recheck. If sane plug goes black again its most likely the coil not firing

if they are all the same and black it really is rich for some reason. Might want to look at o2 sensor voltages and currents to see if there might be a bad wire or sensor

we need data

 

Heres the o2 sensor currents and voltages. You want sensor 1 currents and sensor 2 voltages

 

Thanks for responding Aarcuda,

these are the values I got earlier …. at idle speed if I have to do get the values at running speed NOT sure how to do that ?? unless somebody is driving and can take a photo of the screens on the scanner ??

oxygen sensor current ( B2 - S1) -0.05 ma oxygen sensor output voltage (0.730V B2 - S2)

oxygen sensor current (B1 - S1) 0.20 ma oxygen sensor output voltage ( 0.125V B1 - S2)

oh yea ! when I removed all the plugs a couple pf weeks ago . all the spark plugs looked the same " black "

 

Did you replace the plugs when they were black? If not thats the first thing we do.

 

NO I didn't replaced any of them .. just cleaned them they are not that old .. kind of new .maybe I need to get new ones now and what kind do you recommend ?

 

Get whatever the OEM plugs are. I just bought a set for my STR but my folder is out in the shop and im too lazy to walk over there now but YES! CHANGE THOSE PLUGS! FIRST THING!
Once they misfire its hard to clean em up because they leave carbon trails that mess with the spark So go get a set of OEM plugs from any parts place and gap em and install them. But post pics of the ones you remove. Mark the plugs or keep them in order when you remove them so we know what plug went where. It might tell us where to look.

In the meantime, read this starting on page 1 and dont stop. it gets good at page 2-13 http://www.jagrepair.com/images/Trai...ive%2006_06.pd
f810 Jag Engine Diagnostic Guide

 

Read this too:
http://www.teacher.starenvirotech.co...8%202006MY.pdf

http://www.jagrepair.com/images/Trai...20-%202000.pdf

 

Not hot. For me it needs to be FULLY hot with hot cats - i.e. drive it then park.

On plugs: STR uses NGK iridium IFR5N10 & the 3.0 platinum I think but I forget which.

 

very much appreciate it Aarcuda.

that is probably what i need to DO , educate my self on this cars ... I plan to go to Autozone this afternoon after work . I believe i got them there , maybe they can exchange them !
also I don't think i gap them before i put them in ?? just assumed they were pre-gap them I will run it again and get the values -- I will make sure photos are taken will post them .. many thanks again guys..

just spoke to my guy at Autozone - he recomended BOSCH platinun 6747 spark plugs ??

 

The stock plug is an NGK. Get thise.

looks like they replaced all 6 plugs and coils most likely without needing to. Never do all 6 coils go bad.

they also replaced the upper intake manifold gasket. Now that would affect all 6 cylinders. But usually itd be lean not rich.

look at the plugs. Get new ngks. And look around the upper intake for a place a gasket like shown below . The problem is near that Gasket I bet

 

these how the old spark plugs look .. I got the new plugs today … I also took another compression test

these is how they look :

cylinders 1,3, 5 180, 180, 180 psi

cylinders 2,4,6 200, 210., 200 psi I just read ; as long as no more than 20% between lowest and highest and above 135 psi " is considered acceptable numbers "

 

Did you wipe out the trims after replacing your evap purge valve? The reason I ask is, if your chronic lean condition has driven your trims high enough to light up your lean codes, creating the excess carbon you see on the plugs, and the now replaced evap purge valve was the source of the vacuum leak the whole time, then the excessive negative trimming (generating a too rich code) will be required in order to work back to proper mixture. Simply state if you disconnected the battery and cycled the ECM, AFTER completing the evap valve purge replacement? I also suspect that it was the under hood valve you replaced, is that accurate?

 

is It - disconnecting the battery and touching together the cables for around 10 seconds ? I believe I did however i can do it again this afternoon ..

what do you think about the compression test results ? thanks ControlIssues..

 

I’m not too excited about those compression numbers but I don’t think it’s the cause of your problem. In my opinion those plugs look great. Maybe a little light I’d like to see a little bit more brown on the white insulator but they don’t look overheated and they definitely aren’t rich. So if you are getting a rich indicator on your DTC it’s not reporting an actual richCondition it might be a bad O2 sensor thinking it’s rich. Or it’s rich and it is being fixed by the computer but I’m not sure how all that algorithm works. But you’re definitely not running rich

 

And I agree with what control issues wrote. You may have had a problem for so long that your fuel trims are way out of whack and now they’re just being corrected not sure how the algorithm works but I would clear out the codes and run it and see if the trims come back into normal ranges. I watched my fuel trims after repairing a vacuum leak and the long-term fuel trims were definitely beingBeing adjusted to remedy the previous link condition that I had so the long-term fuel trims were high for a long period of time but eventually kept coming down in now or right around zero

 

By the way I’m not sure if it was your post or not but I recall seeing another post recently about somebody else with a V6 that had very similar compression numbers as you do wear one bank was in the 210 range and the other bank was in the 180 range but that guy I believe has somebody replace the head or do some work on the head and I was thinking that maybe it was mailed more or different gasket was you so I changed one banks compression numbers. I just find it odd that I remember to post and I believe the different posters both having very similar bank the bankCompression numbers

 

Clear your trims and watch them build on your iCarsoft.

The fuel trims have two loops, short term and long term. The short term look at the primary O sensor only on its own bank. The secondary O sensor monitors the performance of the cat, only the primary sensor tunes the motor. The short term trim loop will enrich the mixture when the primary O sensor reads lean and lean the mixture back out once the efffect show up on the O sensor. Expect it to cycle.

The long term loop is a slower response loop watching the effects of the short term loop on the O sensor over a greater period of time.

Together, they form total trim. This will drive the pulse rate of your injectors. Though the pressure or the fuel system is modulated, it is still trying to keep a consistent pressure value at the tip of the injectors. This explains slightly higher fuel pressure during periods of higher fuel draw.

These over simplified factors accompany calculations coming from other inputs;

The TPS, to see what is being asked of the system.

The MAF, to see how much air is being entered.

The IAT, to calculate the density of entering air.

And the MAP, to sense the engines subjected load and altitude.

The engine then predicts the amount of fuel that would be required to support that volume and condition of air to handle the current degree of work. An injector pulse rate at a known fuel pressure delivers that component.

It would be nice to live in a perfect world, but my bathroom mirror tells me that things degrade over time. Spark intensity diminishes, injectors become a bit more restricted, and TOLERABLE levels of vacuum leakage develop. That is the purpose for the trims to adjust for the ECM'S programmed fuel table.

It is highly unlikely for so many parts to be bad simultaneously. Stop buying so much stuff. Your mix is off and the check engine lamp is telling you so because of the total trim. You have renewed your ignition system, I agree with Cuda, those should fire fine. You also have sufficient compression to burn a fuel mixture. And I will be sure that you have a decent fuel filter in place and your pressure is fine. Let's believe for a moment that you don't have 6 bad injectors. That leaves air.

A vacuum leak introduces air that the engine doesn't know about. The calculations are based strictly of what the MAF has reported to the ECM. You have been chasing a leak for a long time now, and this is the first time you have reported a rich code. I find that to be the most interesting piece.

Again, clear the trims, run the engine and see how the trims accumulate. Also understand that varying engine loads, engine speeds, engine and air temperatures, all impart different needs for different fuel rates. Understand that the engine is only extracting energy from fuel and applying it on the crank. Does wide open throttle in gear and underway push the short term up and does deceleration in a lower gear call it to lean out? It should. Over time the short term smooths the cycles out and adjusts the long term.

Apologies for the length, but this is how I interpret the data.

Lastly, considering that you have a printing press making dollar bills in the basement. Get a 1/4 in drive torque wrench for setting the plenum bolts. That is an important seal to make. It doesn't need a lot of tension, it needs the right amount of tension.

Good luck.

 

oh boy! you guys are a wealth of acknowledge !

i m going to closely study your much appreciated responses .. I m stopping buying stuff I m at the end of half guessing spending game. ControlIssues i will follow all your directions !

also I m planning on using a torque wrench on the plenum bolts today after work. Aarcuda it was probably me that posted those compression results in one my threads - although Didn't had an issue gaskets .

I do believe the compression numbers ain't great BUT doesn't merit tearing it down again ! DONT think ..!!

one more thought ! i m giving you guys a warning LOL.. I Do feel i m getting close to the finish line with you guys help !!

I read somewhere the engine coolant sensor may also be sending the wrong temp to the ECM ??