crazylane

iTrader: (19)

Well I put my cam in last week, the specs are in my sig, nothing to big...

This weekend I went and had it tuned, and found out that I had a lazy o2 sensor on the driver side bank. My tuner said there was nothing more he could really do with it, until I get those taken care off.

Well the question I have is, right now I still have the old o2's, and when driving, it is running so rich that, it almost floods the car out it seems. At 1300 to 2200 RPM's, the car surges and bucks like mad. I actually have to pop the throttle to get it to clean up, and be able to accelerate. Will these new o2's take care of this problem, with out having to go back to the tuner and have him reajust the tune? Or do I need to take it back and have him mess with it some more with the new o2's in the car?

And also, I am guessing it would be a wise Idea to replace the sparkplugs as well right? Just idling to warm up in front of the house, it leaves massive amounts of black **** allover the concrete. So I could only imagine what the inside looks like ha ha.

lane

edcmat-l1

iTrader: (10)

If he gets the tune close enough, you can run it in open loop. Just turn the 02s off, and when you get them replaced, turn em back on.

jimmyblue

iTrader: (11)

Forcing open loop would be good just to determine
whether the "lazy O2s" are the cause or just a
symptom of something else.

I had what I think was a "fuel loop oscillation" after
my cam swap. The way it acted made me think that
the VE table was not right in the MAP dimension, the
MAP and the O2 voltages were bouncing together
(with some lag). As if the VE relation to MAP was
over-represented.

As I leaned out the bottom end it got a whole lot
better. This is where I'd start, cleaning up the
airflow side (VE).

edcmat-l1

iTrader: (10)

I wasnt meaning force open loop to diagnose it, what I meant was tune the VE in open loop, and once its dialed in it should run fine in open loop, until the 02 problem is corrected, then he should be able to switch it back to closed loop, provided the 02s are functioning properly.
I've had to do this on several cars that had "lazy" 02s, or had them in a bad spot were they didnt want to oscillate fast enough.

98Z28CobraKiller

iTrader: (17)

I like to throw the stock O2's in the garbage. Buy a wideband, have it tuned in open loop and never orry about those pieces of **** again. If you find that you are still experiencing surging after the O2 problem is resolved, tell your tuner to drop the timing way down in the surging area. I believe that the stock timing table has in excess of 40* of timing in that area. I've had to drop them into the 17-20* range in that area in order to smooth it out. Usually alittle extra fuel (13.5:1 AFR) will help to smooth it out. M6 cars with cam are more prone to the bucking and surging. Big stalled autos soak the surge right up.