Warmup Transient Fueling

[Blades]

Can someone please explain this? How can I add slightly more fuel.. After startup, the car runs a tad bit on the lean side.

Also.. Since I have a cam that causes the MAP values to be a little "twitchy", should I adjust the delta map for transient fueling enable? I bumped it up from 1.5 to 2.0.

I also have adjusted Evap factor:
X * 1.01 in cells 20-50, X * 1.007 in cell 60, and X * 1.005 in cells 70-100.

And the Impact factor:
X * .98 in cells 20-50, X * .99 in 60, X * .995 in 70-100.

I am getting a very rich dip after I tip into the throttle and let off. This also holds true for when the converter locks up. Should I have adjusted the Accel/Decel ratio as well?

Last question: Is transient fueling working off the Primary VE? Suppose a cam was installed without dialing down the VE in the lower rpm range, would this look like transient fueling was "off" in that range? FWIW, I am running MAF only.

[EC_Tune]

You are in uncharted waters there but there is a writeup on transient fueling around here in the General section.

[Blades]

I noticed a better throttle response by doing this. However, I believe this is only necessary when switching to bigger injectors. I still get rich dips after a quick WOT blast. Is this something else?

[EC_Tune]

Yeah, thats the decel side. But when you push in a little extra fuel because the spray pattern hits the ports more you need to change the Evap side as well or you will get the rich dips.

[Blades]

Yes, I did increase the evap side.. not as much as I decreased the impact side.. Going back to my original question.. What about warmup.. aka stomp compensation? What does an increase/decrease in the Base Mass do? This was never mentioned in the original "Lets Discuss Transient Fuel" post.

[Michael@L&M Engines]

A basic concept of transient fuel is that as load increases transient fuel increases, as load decreases transient fuel decreases.

As an example, if no transient fuel was compensated for when load increases cylinder mixture leans, as load decreases cylinder mixture richens.

There was an excellent primer on transient fuel in one of the stickies on this site.

Michael

[Michael@L&M Engines]

Has anyone experienced my post in this thread?

http://www.hptuners.com/forum/showthread.php?t=10872

Here is the post as copied-

I have just taken delivery of VCM Editor and downloaded 3 - 2003 truck 5.3 stock files from the repository for examination and I find that all 3 do not have acceleration enrichment nor transient fueling parameters under the tabs.

Is this due to these VIN's not having these parameters available in HP Tuners?

Why would they not be available?

I use these tables extensively in SCT software for the Fords, which SCT generally only allows these parameters to be available to individuals that have "Calibrator" status.

For an added explaination and model of transient fuel one can refer to John Heywood's text "Internal Combustion Engine".

Michael
__________________
Michael Rauscher
L&M Engines
246 E. County Line Rd
Hatboro, PA 19040
215-675-8485

[EC_Tune]

Yeah, some vehicles don't have those tables included. You can request them though. If they don't exist though: Then you can't have them.

[Blades]

A basic concept of transient fuel is that as load increases transient fuel increases, as load decreases transient fuel decreases.

As an example, if no transient fuel was compensated for when load increases cylinder mixture leans, as load decreases cylinder mixture richens.

There was an excellent primer on transient fuel in one of the stickies on this site.

Michael

So if i was running rich when I let off the throttle after WOT. (and I adjusted both evap and impact) What would I need to adjust? Would I need to adjust the evap side a bit more? I guess I could have dfco kick on 'sooner'. I think it might be dfco thrown off by my cam.

Does anyone know about the base mass value for warmup transient fuel? What does increasing/decreasing this value do? I am mainly concerned about my warmup lean condition.

[Michael@L&M Engines]

So if i was running rich when I let off the throttle after WOT. (and I adjusted both evap and impact) What would I need to adjust? Would I need to adjust the evap side a bit more? I guess I could have dfco kick on 'sooner'. I think it might be dfco thrown off by my cam.

Does anyone know about the base mass value for warmup transient fuel? What does increasing/decreasing this value do? I am mainly concerned about my warmup lean condition.

Due to just acquiring HP Tuners and not being familiar with the specific parameters I can only provide basic concepts.

On a transition from WOT to a lower throttle position, load immediately lowers causing the increase of transient film during WOT/High load to start to evaporate as the throttle position lowers causing a rich condition.

The pressure in the manifold lowers and as such lowers the boiling point/evaporation temperature causing the film/drops to vaporize and fatten up the mixture.

So in that case one would adjust the EVAP parameter, I would not know what direction the value would need to go, which is software/logic dependant.

Now, on warmup, inlet air/manifold/port temps are low and transient film increases causing a lean condition which will trend towards rich as temps rise.

This is also an Evap parameter rpm/load vs temp/time.

Impact transient is mostly injector/injector placement vs load dependent.

I hope I have not mudded the waters with this explaination.

Michael

[Blades]

Thanks a lot. Let me know if you ever get to mess around with Warmup Transient Fueling.. I am curious to see what raising/lowering the base mass does.. I want to get rid of my lean startup so bad! Then again, this could also (partially) be my wideband bugging out from the low LSA cam at idle.

[Chris@HPTuners]

http://delphi.com/pdf/techpapers/1999-01-0553.PDF

[Michael@L&M Engines]

http://delphi.com/pdf/techpapers/1999-01-0553.PDF

Thank You, I look forward to printing this so I can review it while on the throne.

Good stuff.

Michael

[Michael@L&M Engines]

Thanks a lot. Let me know if you ever get to mess around with Warmup Transient Fueling.. I am curious to see what raising/lowering the base mass does.. I want to get rid of my lean startup so bad! Then again, this could also (partially) be my wideband bugging out from the low LSA cam at idle.

Screw around with the values and let me know!!!!

Valve overlap will add to the exhaust stream excess O2 due to overlap and poor combustion.

In some extreme cases on Fords I have set idle to open loop then CL as rpm increases.

Michael

[Blades]

112 LSA will do that I guess.. I'm in open loop everywhere. What is a common idle AFR you are seeing with low LSA cams? I just updated my sig with my car and mods.. Check it out.

2006 Trailblazer SS (352RWHP, 353RWTQ Before Cam)
-HpTuners w/ Innovate LC1 Wideband (running open loop)
-CAI, SW Long Tubes, O/R Y, LMF CB.
New Mods: Vig 3400, 222/224 566/568 112LSACam.

Apparently my sig isn't showing up.. Look above..