Throttle Cracker and Follower

[DaddySS]

Todays dumb question:

The VE table tells the PCM how much air the engine is using at RPM and MAP and therefor how much fuel it it should add.

The throttle cracker adds to that based RPM and Speed and the throttle cracker adds based on TPS (and multiplied by the RPM multiplier).

So, are the throttle cracker and follower an additional airflow/fueling signal to the PCM that in effect would be same as adding to the VE if all conditions were static or do they do something different?

I ask because I am running lean at like 7% to 10% throttle in the 1400 to 2400 rpm range and trying to figure out the best strategy to solve it. All other conditions - idle, higher RPM and throttle, deceleration, etc. are nearly perfect so I don't want to affect anything except the problem area.

Thanks!

[dfe1]

Under the conditions you're describing, (assuming steady state operation at the throttle position and rpm you mention) throttle follower and cracker should be pretty well out of the picture. Under the idle folder, look at the follower and cracker descriptions and see if that makes sense. Sounds like you need to adjust your VE table or you're running into DFCO.

[SSpdDmon]

Throttle cracker and throttle follower do allow air into the engine via the IAC. However, it's post MAF air that's already metered. Therefore, fueling should have already been calculated (even if you're running SD). They are for driveability alone.

If you're running lean, you need to add fuel via the VE or MAF tables (or if you're old school, the Injector Flow Rate table or Commanded Fueling in Open Loop Table).

[WiseGuyZ06]

Listen to this guy he knows what he's talking about!!!!

[WiseGuyZ06]

Throttle cracker and throttle follower do allow air into the engine via the IAC. However, it's post MAF air that's already metered. Therefore, fueling should have already been calculated (even if you're running SD). They are for driveability alone.

If you're running lean, you need to add fuel via the VE or MAF tables (or if you're old school, the Injector Flow Rate table or Commanded Fueling in Open Loop Table).

Listen to this guy he knows what he's talking about!!!

[DaddySS]

Thanks for the replies gang, so looking at my log and tune, even though my VE table seems high alredy in that range I should add more to bring the fueling up?

I would also appreciate it if you had a look to see if there is anything else I'm missing?

[SSpdDmon]

Doesn't look too high to me...

Here's what my VE looks like with my setup.

[ViolatorTA]

Wow!!!!! How do you get such a nice smooth table and keep fueling right? I'm figuring you're cammed with the hp in your sig. Here's mine and it still isn't dialed in.

[SSpdDmon]

Wow!!!!! How do you get such a nice smooth table and keep fueling right? I'm figuring you're cammed with the hp in your sig. Here's mine and it still isn't dialed in.

That's just it. You can dial it in for the cell at a given rpm/kpa. But, once you stray from the center of that cell and the pcm starts interpolating the fueling is going to be off a little - usually up to 3~4% in some instances. I'm still tweaking mine a bit here and there. Once I'm done, I plan on increasing it 2% so that the variance is -2~2% instead of 0~4%.

[DaddySS]

So as to compare, mine is in % and yours is in units kelvin, how do I change the units - it's not imperial versus metric......???