The Dragon

iTrader: (6)

I'm getting misfires below optimal running temps eg. 120* F and 154* F.

Do I pull timing somewhere in the table? If so, where? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Could this have been effected by gapping my plugs at .50 instead of the .59 I was running before?

Thanks fellas! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Ragtop 99

iTrader: (7)

Do the misfires occur at idle or while running? on all cylinders or just certain ones?

Normally a big gap can lead to misfire rather than a normal one.

2000WhiteZ28

Just a thought:

Big cam, low idle will log a buttload of misfires. Not that you really are misfiring, but the ECM sees it that way.

The Dragon

iTrader: (6)

Misfires occur at idle in open-loop or during warm-up.
I was told on Edit e-mail to modify the idle and low rpm tables. Advice was to set the value to 32000.

This is vague. Could anyone elaborate? I located the tables in Engine Diagnostics.
Also, there are 2 tables referring to low rpm: one says "low rpm" and the other says "low rpm by cyl". The other says "idle by cyl".
Obviously I modify the idle by cyl, but which low rpm?
Do I make all of the cells 32000? Should I only change certain cells?

Anyone know about this one? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

ChrisB

Easiest technique might be to raise the minimum temperature to enable misfire detection - since you indicate that your problem only occurs below normal operating temperatures.

I would suggest verifying that the problem is not localized to one cylinder (that it isn't a real misfire problem per se, but rather a function of the cam size, etc.)

Chris

The Dragon

iTrader: (6)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ChrisB:
<strong> Easiest technique might be to raise the minimum temperature to enable misfire detection - since you indicate that your problem only occurs below normal operating temperatures.

I would suggest verifying that the problem is not localized to one cylinder (that it isn't a real misfire problem per se, but rather a function of the cam size, etc.)

Chris </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Should I clear the codes then tap it from a cold start monitoring each cylinder misfire? Wouldn't I have to do this more than once in order to see if the misfires are localized?

Ragtop 99

iTrader: (7)

on a cold start, log the current misfires for each cylinder. You can log all 8 at once. I'd also log coolant temp.

Team ZR-1

It is common with a non stock cam and the other changes you have is to have a loppy idle, this would cause a problem as the crank position sensor then sees a slight uneven change in crank rotation.
Cold weather will cause richer fuel trims so it maybe your too rich with a cold engine.

Work in idle in LS1edit, when engine is cold start with higher RPMs and as engine warms up reduce idle speed.
Example with my stroker engine cold idle is 1050, and when fully warmed its at 925 RPMs, this will reduce the loping and tripping false misfires.
As to misfire, raise the starting cold temp when misfire is learning. As to counts, 32000 would mean a long enough wait between counts that is will miss the false misfires between that timeframe.

If you think you really have true misfires and get multi misfires which trigger P0300, your better off scanning for Primary misfire and Secondary misfire piston value for it then tell you which piston misfired first ( Primary) and the piston that then misfired ( secondary)
those two paramters will have the piston number, its not a counter.

I would not pull timing, its not the cause and proper tuning will correct false and real misfires once you determine if its false due to cam grind or real if too rich AFR.

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by The Dragon:
<strong> I'm getting misfires below optimal running temps eg. 120* F and 154* F.

Do I pull timing somewhere in the table? If so, where? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Could this have been effected by gapping my plugs at .50 instead of the .59 I was running before?

Thanks fellas! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">

The Dragon

iTrader: (6)

Thanks Ragtop <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Logging each cyl mis was gonna be my next step.

Team ZR1: Now that . . . is elaborating! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Thanks for the info <img border="0" alt="[driving]" title="" src="graemlins/gr_driving3.gif" />

The Dragon

iTrader: (6)

What would I modify in order to rectify idle searching?
Occaisionally on start-up, my rpm's drop low eg. 4-500 and "search for idle" for a few seconds (almost to the point of stalling). This does not occur every start-up (never when ice cold either).
Would timing be needed here? Or A/F adjustment? If so for either, where and what?

Thank you again!

<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

1fastWS6

iTrader: (3)

I *think* you need to modify the IAC park position numbers. Not sure how though.

I need to do this for my new cam too.

Can someone elaborate on this for us?

Craig

The Dragon

iTrader: (6)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Team ZR-1:
<strong>
. . . As to misfire, raise the starting cold temp when misfire is learning. As to counts, 32000 would mean a long enough wait between counts that is will miss the false misfires between that timeframe. . .
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by The Dragon:
<strong> I'm getting misfires below optimal running temps eg. 120* F and 154* F.
Thanks fellas! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"></strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Where exactly would I set this value?
Low rpm, low rpm by cyl, or idle by cyl? All of these or one or two of them?
Do I set all cells to 32000 (this sounds right) or just a few cells?

Thank You!

The Dragon

iTrader: (6)

tja

too just above

The Dragon

iTrader: (6)

Movin' above again <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />