normal spark advance at idle in DM?

[Flyin Ryan]

I ask because I was screwing around with the truck for an hour or so yesterday and ran dm for a few minutes and noticed that the timing or spark advance in DM seemed kinda high to me.. I don't really know much about what it should be at idle in DM so im asking.. what's the norm for spark advance in DM at idle in park?

Also noticed from previous data logs that with my pitbull chip and 2bar I was getting 24.3 or .9 spark advance in DM but with this 3 bar waller chip it's giving me 34.5... could it just be that the 3 bar chip is more aggressive or is it wack?

only change is that i upped the idle a tad to 825rpm to help with the efan load until I can get a better alternator.. I just put the stocker back in for now and with the idle a bit higher there is no voltage spikes or draws... think this could be it?

Didn't get to take the truck for a spin yesterday when I noticed this because having a new born consumes every minute of your life but i'll run it today and log it

 

[TYTILIDIE]

Re: normal spark advance at idle in DM?

35* could work of depending on a few things. I had mine that high but kept getting a hunting idle so I turned it down to around 25*.

 

[Flyin Ryan]

Re: normal spark advance at idle in DM?

what does it depend on?

just found this

Timing - you will see 20-30 at idle/cruise, and should see 12-15 at WOT/full boost. Racier chips will push the timing values at WOT to 17-19 possibly.

so I guess it's cool .... i'll data log it around the neighborhood I guess and see what happens on DM

 

[dgoodhue]

Re: normal spark advance at idle in DM?

what does it depend on?

just found this



so I guess it's cool .... i'll data log it around the neighborhood I guess and see what happens on DM

It depends on what programmed in the timing table. Vaccuum and RPM determine what cell the ECM looks up in the table.

 

[Don W.]

Re: normal spark advance at idle in DM?

At idle it almost doesn't matter. It'll run smoth with outragious advance because the cylinder pressures are so low. Knock will be almost non existant for the same reason. Once you leave idle things change of course.

 

[TYTILIDIE]

Re: normal spark advance at idle in DM?

At idle it almost doesn't matter. It'll run smoth with outragious advance because the cylinder pressures are so low. Knock will be almost non existant for the same reason. Once you leave idle things change of course.

This is actually not always true. I had my timing at 35* and my idle was erratic. I had to take it down to 25*. No matter how much fuel I added or pulled it wouldnt run right with that much timing, every truck could be different though.

 

[Don W.]

Re: normal spark advance at idle in DM?

This is actually not always true. I had my timing at 35* and my idle was erratic. I had to take it down to 25*. No matter how much fuel I added or pulled it wouldnt run right with that much timing, every truck could be different though.

Correct, there will be a point where things go south. It can be fun though, to add advance and watch the RPM's go up. To a point of course... :tup:

 

[Flyin Ryan]

Re: normal spark advance at idle in DM?

Correct, there will be a point where things go south. It can be fun though, to add advance and watch the RPM's go up. To a point of course... :tup:

so if you were to have too high of an advance, your idle rpms would raise or be higher then normal?

 

[TYTILIDIE]

Re: normal spark advance at idle in DM?

so if you were to have too high of an advance, your idle rpms would raise or be higher then normal?

Yep.

 

[Don W.]

Re: normal spark advance at idle in DM?

It's not as dramatic with computer controls as it is with carbs. You remember carbs don't ya?