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-   -   TPS based AE trouble. (https://www.miataturbo.net/megasquirt-18/tps-based-ae-trouble-100023/)

MasMiata 05-02-2019 11:51 AM

TPS based AE trouble.
 
1 Attachment(s)
Have got my car running on a DIYPNP, bone stock 99NB, and I think I've got the VE table worked out for the most part, but I'm having trouble understanding TPS AE. When I smack the throttle I get a sudden lean condition, the my AE kicks in and then suddenly it pegs rich. The car seems to rev freely, but in the log it looks like i drop maybe 20-30 rpm when I initially smack the throttle then the RPMs climb. I'm a newb at this tuning stuff, so please flame lightly, slight roasts only. I have attached most recent log and MSQ.

thebigtuna 05-02-2019 12:11 PM

It took me a while to figure out exactly what is being targeted. I always thought you were trying to get rid of the lean spike, truth is afr doesn't matter at all for AE. What you are trying to do is get the rpm to rise as close to the initial crack of the trottle. I like to log PW, TPSdot, and RPM (as I only use tps, no map). You then try to get the rpm to rise as quickly and smoothly after as possible. Laggy rpm increase is too rich, dip before rise is too lean. Someone else correct me if I'm wrong, but this is how I understand it.

Also I have no way to look at your tune, so I'm just throwing this out there. AE is the last thing you tune, your VE table (if its not smooth and well done) will heavily effect AE tuning.

MasMiata 05-02-2019 12:34 PM

This is also how AE was explained to me, but I just want some input on if I'm on the right track, Want to be dumping the correct amount of fuel. My VE is smooth and I'm only adding 0.9 ms PW at 30%/s TPSdot and 2.5 ms PW at 1000%/s TPSdot .

thebigtuna 05-02-2019 12:37 PM

The exact values will be different for each car and setup. Look at the rpm and it will tell you if you're on the right track or if you need to adjust it richer or leaner.

MasMiata 05-02-2019 01:01 PM


Originally Posted by thebigtuna (Post 1533374)
The exact values will be different for each car and setup. Look at the rpm and it will tell you if you're on the right track or if you need to adjust it richer or leaner.

Right I know that it will be different car to car. So right, my values mean diddly squat. I will try this way and just tune for rpm rather than AFR. Thanks, other input is welcome too.

thebigtuna 05-02-2019 01:16 PM

I will say from looking at my values, at a 1000%/s tps dot my PW is 6.0 ms and at 108%/s im at 3.6 ms. Both of which are still a tad lean for my taste. Idle pw is 1.7 or so. A little over double your idle pw I believe is a good start for your lower tpsdot values.

MasMiata 05-02-2019 01:26 PM


Originally Posted by thebigtuna (Post 1533383)
I will say from looking at my values, at a 1000%/s tps dot my PW is 6.0 ms and at 108%/s im at 3.6 ms. Both of which are still a tad lean for my taste. Idle pw is 1.7 or so. A little over double your idle pw I believe is a good start for your lower tpsdot values.

So your are suggesting that, if i have a idle pw of 2.6 or so, at 100%/s my pw should be 5.2 or a little richer?

thebigtuna 05-02-2019 01:46 PM

It's what I've found to work so far as a decent starting point. It was also recommended in a video that was linked once,
. YMMV. My beginning values are decent for getting very little dip and a decent response. Try things out and see what works for you.

MasMiata 05-02-2019 01:53 PM


Originally Posted by thebigtuna (Post 1533389)
It's what I've found to work so far as a decent starting point. It was also recommended in a video that was linked once, https://www.youtube.com/watch?v=HSE3CxaWF-I&t=748s. YMMV. My beginning values are decent for getting very little dip and a decent response. Try things out and see what works for you.

Yes I remember this video, will try this out tonight and see if it responds better. Thank you.

MasMiata 05-03-2019 09:48 AM

Tried the way the video suggested and yes it seems to be doing better. Free rev feels smooth and RPM climbs as soon as the throttle stabbed. Throttle response has improved too. Thanks


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