Ok I had my buddy scan my car again with the snap on scanner..

Heres what I have for IDLE

TPS % = 0.55
RPM's 780's - 820's
O2B1 S1- 70MV-900MV Flucuates
02B2 S1 - 70MV-900MV Flucuates
O2B1 S2- 443MV
O2B2 S2 - 443MV
CLOSED LOOP
ST TRIM -1 = -2
ST TRIM -2 = -2
LT TRIM -1 = 4
LT TRIM -2 = 0
MAP (V) 1.09-1.15
MAP (KPA) 30-35
BARO (V) 4.79
BARO (KPA) 101
COOLANT 83C
MAF (GM/SEC) 7.30-8.20
INTAKE AIR = 38C
IAC POSITION = 33
IAC MEMORY = 35
FT CELL =16
ENGINE LOAD 3%
KNOCK RETARD= O
SPARK ADVANCE = 17-20%
COP DUTY CYCLE = 0
START CLNT = 79C
RPM LO RES = 35 -1.15
RPM FINE RES = 790-810

DID A WOT RUN ON 1'ST-2'ND GEAR

KNOCK RETARD = 2.1
ENGINE LOAD = 11%

BACK TO IDLE

FT LEARN WENT FROM NO TO YES THEN BACK TO NO?????

Now my question is why do I have somewhat of a rough idle? O2's (86k) or is it something else???

Thank you in advance... Fred what do you get out of this? You seem to be one of the only guys who know all these #'s and sensors and Rob. Is everything looking good or no?

 

ttt

 

Fred, Rob , Do you guys know???

 

numbers are good except for your downstream o2 sensors. if they are consistently that high soon you will be flagging catalyst efficiency codes. i think you said idle testing is what you did, not the best way to determine catalyst degradation, needs a few miles at fwy speed to get accurate numbers that will be something that you can base any diagnosis of the cats on. looking for lazy readings around 100mv once the cats are hot. the old term integrator is called fuel trim now. if you saw the yes\no happen at full throttle thats when you would drop out of closed loop, and what does the pcm rely on then? nothing it has learned, thats for sure. it relies on the pre-programmed values in its look up tables. thats why it said no at wot cuz it isnt using any learned values. rough idle may be a vacuum leak somewhere on bank 1-thats the drivers side, you are showing the pcm has been adding fuel to that side, and its learned it and placed it at 4 percent long term. check it out with some carb spray-check the egr valve too. if you get ahold of the tool again do a misfire diagnostic it takes a second and access the miss history too. that will usually tell you alot more of what you are looking for.

 

doh-it says right there plain as day-hollow cats-well, there ya go. did pcmsforless disable that codes group with the reflash? i am unsure whether or not that is even possible with obd2 stuff. i know that i could with tc back when i was burning chips. maybe the same parameters exist with obd2 stuff. i could disable quite a few of the most problematic codes.

 

Integrator = short term fuel trim
BLM = long term fuel trim
Depends.... if it was adding fuel in the upper load/rpm BLM cells, it will use the BLM's (long term fuel corrections) from Cell 15. If it was cutting fuel, it will default to Cell 18 and lock the BLM's at 128 (0%).

And, when you go WOT, using GM's terminology, even though it stops reading the feedback from the O2 sensors, GM referes to this as "power enrichment mode" rather than open loop. "FT Learn = No" means it is not accepting feedback to alter the long term corrections. Mostly semantics. The reason you saw no -yes - no during your WOT balst including 1st and 2nd gear is probably the fact that you lifted throttle on the 1->2 shift, throwing the PCM briefly back into closed loop/learn mode, when the TPP% no longer exceded the TPP% vs RPM table programmed into the PCM.

I don't see anything in the "idle" numbers that would indicate a problem that would cause a misfire. The LT fuel corrections aren't radically different, and the small percentage would indicate you had a pretty good tune, with regard to injector constants, MAF calibration, etc. I would agree that the problem is likely in Bank 1.

Just how rough is the idle? Are we talking a "twitch" once in a while, or are we talking a shake that would knock your teeth loose, or something in between?

You wouldn't have happened to "port" your MAF???

 

I feel like its a shakey idle. it twitches a bit. Nothing that would kill me but a little off. is the car supposed to idle from 780's to 820's? What is bank 1 ?

I havent had any more misfire issues since I replaced my cyl # 5 wire. just a shakey idle. are all the #'s where they should be for my car? my car runs pretty good, seems strong, its just the idle. both of the do-nutt gaskets on my y-pipe are leaking and I think I may have a slight header gasket leak as well. those could be factors in the idle too? correct? my guess would be O2 sensors? how about you?

with the fuel trim stuff, is that all right?
ST TRIM -1 = -2
ST TRIM -2 = -2
LT TRIM -1 = 4
LT TRIM -2 = 0

I dont know what ANY of that means? how come two of them are -2 and one is 4 and the other is zero ?

one side of the car is leaner/richer then the other?

Thanks

 

The idle speed depends what Madwolf programmed it for. 800rpm is "stock" for an M6. And it wouldn't be unusual to see +/- 25rpm at idle. Sounds normal, when reading RPM on a scanner. The tach might indicate 100-200rpm higher.

The cast iron LS1-derived 4.8L in my 2001 Silverado has quite a "stumble" at idle, sometimes. But it doesn't show up as a misfire. Appears that they jerk the timing around in the stock program to try and control idle at low RPM. It is remotely possible that Madwolf is using a similar technique to try and stabilize your idle, although you ususally only do that with a hairy cam.

Is it possible your EGR blockoff plates are leaking? Has the riser tube from the header been completely removed?


The numbers for ST TRIM (short term fuel trim) are not very important.... they look fine. Its the LT TRIM (long term fuel trim) that is of interest. Bank 2 (passenger side of the engine, cylinders 2, 4, 6, 8) is in perfect balance at idle. The PCM is calculating the fuel required to match the air measured by your MAF, and the O2 sensor is telling it the calculations are giving the correct rresult, hence 0% correction is required.

On Bank 1 (drivers side of engine, cylinders 1, 3, 5, 7) the PCM is slightly "off" on the calculation. The O2 sensor on that side sees the results as "lean", so the PCM is adding 4% extra fuel to the calculations to make the A/F ratio at idle correct. This is not a very large correction, and is within normal limits.... actually, like I said, it indicates Madwolf got the injector constans and MAF calibration correct, if he even had to change them. And the small difference between Bank 1 and Bank 2 isn't anything unusual. But, if you were having a problem with a small misfire at idle on Bank 1, it could show up with results you got. But that is purely speculation, since the long term corrections are not anything unusual.

Did you ever check the injectors? You might try swapping the intectors from Bank 1 to Bank 2 and see if the small difference in long term corrections moves to the opposite side. But if this is just an occasional "twitch" at idle, I wouldn't worry about it.

 

check the misfire history, before you change anything around.

 

I have 93 style headers so no tube on my headers, just the two plates at the back on the manifold. seem to be good. would having two 8mm wires on the 1,3,5,7 side affect it like so? i have two 8mms and two 8.5s I havent changed my new wires in yet... maybe the o2 on that side is bad? they do have 87k on them now. Its just a little twitch at idle, kinda feels like it should but with that twitch u had said....

 

Sounds like some it's time for maintenance work...

Plugs
Wires
Fuel Filter
Trans Filter (A4)
Drain and Fill Rear End Fluid

+ Double check to see if you didn't lose the small white plastic breather in the top right hand side of the axle housing... NOT related to any of your problems, but ALOT of people don't know it's there!

Also might be a good time to see if that intake is dry...

Just some maint. suggestions if you havn't already done them.

Oh yeah, double check those headers to see if they're aren't leaking.