Trying to make sense of fuel: accel enrich number

[93white3400z]

Hi,

I'm running MS3 1.4 firmware. I'm getting a bit of jerking when cold out during AE. Even fully warm up, it doesn't seems as smooth as I would like it to be. I was looking at my data log and I'm seeing a lot of fuel enrichment that I cannot really understand where it comes from. I have attached my datalog and MSQ to this post and I also added few screenshots as well just for an easy quick look.

In the example (screenshot) below, at 19.4 tpsDOT, fuel: Accel enrich is at 130 (Accel PW at 1.7ms). That is fully warmed up. First, my tpsDOT threshold is at 40 so I'm not sure I understand why it's triggering in the first place, but I'm even more confused by the 130% of fuel. Where does that number comes from ? At 200 tpsDOT, I'm adding 2% (req fuel is at 8.5ms) so that's 0.17ms I believe. At lower tpsDOT, the added PW should be even less than that I would think.

I'm happy to hear what anybody as to say on this as I'm a bit confused by the numbers right now.

Thanks

[slow_hemi6]

Maybe not a lot of help but I say slider and greying be damned, I set my map dot threshold to 900 to make sure it is not doing anything when I run 100% tps AE. I also define my lowest point on the table to below my tps threshold level. Your lowest point is 200 but your threshold is 40? So if you go over your 40% threshold it will add undefined until you hit 200% ? I am not the type to assume undefined = 0.

[93white3400z]

I would think it would interpolate assuming 0 tpsdot = 0% added fuel but maybe I'm wrong. I'm also assuming that 100% TPS AE mean it won't use MAP enrichment at all no matter the others settings. I really hope these two assumptions are correct. Hopefully somebody will chime in with that info

[kjones6039]

I say slider and greying be damned, I set my map dot threshold to 900 to make sure it is not doing anything when I run 100% tps AE.

Absolutely agreed! In fact, I run mine at 1000 just to be sure!

Ken

[Marek]

Perhaps you shoould try to think of it as an integral. It's like the area under the graph when the rate of change is mapped per second - the longer the acceleration goes on, the bigger the area under the graph and the bigger the shot of extra fuel.

By setting a threshold amount you stop it cutting in if you stab the throttle hard but very briefly, or if you open up the throttle slowly but consistently over a longer time frame. In the first case you have a tall but thin spike and in the second you have a flat but very wide spike and in neither case do you particularly want extra fuel, but when you are genuinely opening up the throttle, you want a temporary richening up of the mixture because the VE map reflects steady not transient fuelling.

kind regards
Marek

[slow_hemi6]

I would think it would interpolate assuming 0 tpsdot = 0% added fuel but maybe I'm wrong. I'm also assuming that 100% TPS AE mean it won't use MAP enrichment at all no matter the others settings. I really hope these two assumptions are correct. Hopefully somebody will chime in with that info

You could just do what I suggested and see if it works. I mean it does work for me and I battled with the AE for quite some time. If you get no improvement then change it back.

[sd1nl]

Problem you have is the following: you have the table upside down. You have the "high" tpsdot values on top of the table, but they should be in the bottom of the table.

This will cause the acceleration enrichment to trigger upside down, meaning high enrichment at low tpsdot and low enrichment at high tpsdot. Completely wrong.

Enter your table the other way round and all your problems will be solved.

Here is an example of a correctly entered table:

image.jpg

[kjones6039]

Problem you have is the following: you have the table upside down.

Also agreed. Although it may be irrelevant, I also zeroed all of the values on the MAP side before setting the slider to 100% TPS.

Ken

[93white3400z]

Thanks to everyone who shimmed in. Turned out sd1nl was right, somehow everything was backward. Made a world of a difference, numbers makes sense now. Makes me wonder how the numbers ended up reversed at some point but whatever Thanks again sd1nl!

[kjones6039]

Makes me wonder how the numbers ended up reversed at some point

As I think back on it......... I'm thinking mine were backward out of the box, a long time ago. I do recall that someone here on the forum had to point it out to me back then.

All academic now of course. Glad to see you got it straightened out!

Ken