More fuel mixture issues...

[Rick Lee]

This is never-ending and it's just killing me. My rebuilt 3.2 with WebCam 20/21 grind is still running rich and there's not much left to replace on this thing. AFM is new, head temp sensor is new. Leakdown #'s are all 96%-98%. With the CO at 2.00%, HC are 700. With CO leaned out to 0.80%, HC shoot to 1500. I have a test pipe on there and the O2 sensor unplugged for now, which I'm told is how they set mixture anyway. Cam timing has been set so that both banks are perfectly matched now- they weren't before. What the hell is left? I'm never gonna pass emissions even with the cat back on and more importantly, I don't want to trash this engine with rich mixture. I'm seriously thinking of getting this issue resolved and then just getting a 993, but that's another post for another time. Oh, and plugs are not fouled!

[john walker's workshop]

98% leakage is not good. did you actually read that on the gauge? usually it's like 4% for a fresh/good engine. it doesn't look like it's running rich so much, it's just not running properly. that's why the high HC. ANYTHING that causes the fuel mix not to burn completely will cause high HC. one bad plug wire, sparkplug, air leak, bent valve, etc. will do it.

[jeff m]

Richard,
That's a lean miss.
It pushes up the HCs
I know nothing about the 3.2, so I can't agvise you on what to set it at, but you obviously have to go richer.
Jeff

[john walker's workshop]

2% would not be considered lean on a 3.2. most run way below 1% and still have very low HC. i'm thinking cams. try disconnecting one injector and see what the CO/HC goes to. one cylinder becomes an air pump then. the emission guys can't tell, as it's not a OBDll system.

[Rick Lee]

I have to go richer? No one who's looked at it has heard a miss.

JW, I didn't perform the leakdown myself, but the printout just says "All cylinders are 96%-98%". Wouldn't a bad plug wire cause a miss? Again, I don't hear one and the car pulls VERY strong.

[john walker's workshop]

a printout may mean that a computer "read" the engine performance. do a real leakdown test and see what shows up.
i'm just saying that ANYTHING that causes an incomplete burn will cause high HC. i just listed a few things that could cause it. did the plug connectors get checked with an ohmmeter? are the injectors stock, or high output?

[Rick Lee]

I don't mean the computer spit out the results. I didn't watch, but I'm pretty sure he did it the old fashioned way and I know he typed it into the notes section of my bill. Injectors are stock and he did not measure plug wire resistance with an ohm meter, as he said he heard no misses. I'm probably going up to see Steve Timmins this week for rear sway bar mounts and will ask him to take a look. What else can cause an incomplete burn? Wrench suggested a shot in the dark was that WebCam sent the wrong cams in a 20/21 box. Sounds crazy, but I've had the wrong fan housing sent to me four times, so ya never know.

[john walker's workshop]

an engine can run pretty good and still have high HC. there may not be any discernable miss. you really have to go over them with a fine toothed comb to figure it out sometimes.

[Rick Lee]

Well, I can live with that and I'm not real worried about emissions inspection right now either. But with those numbers I listed above, am I doing any damage to the engine? Will this richness dilute my oil? How soon?

[Eric Mckenna]

Originally posted by Richard LeSchander
am I doing any damage to the engine? Will this richness dilute my oil? How soon?

bump..
BUMP!!

I would like to know the answer to that question..
Eric

[Mike Kast]

hmmmmmmmmmm... now my curiosity has also been aroused...
And in the words of the great intellectual Butt-Head---"huh huh... I said aroused"

[RoninLB]

Originally posted by Richard LeSchander
Will this richness dilute my oil?

so this means that your convinced that your running rich, right.. or it's a maybe..

Widebody/Thom Discovered he was running rich thru an oil analysis..
that's all I'm worth on this one.......Ron