What is this stumble?
 

So I've got some kind of stumble when I stomp on it at about 60mph in 6th gear. It never did this before when I had the 5-speed, but since then I replaced the transmission, and had the engine out, and re-did a bunch of vacuum lines, and removed some emissions crap, and cleaned a lot of stuff.

Thoughts on what could cause this? I attached a quick log of it happening, and the msq I'm using now.

For what it's worth, it will do this in at least 4-5-6 throught that RPM range. I think in 3rd and below, the RPMs climb too fast to notice the problem, or to cause it.

So is everybody stumped, or is it something so simple that you're all disgusted that I don't see it?

I have another log that I took that day that may have more info. The only thing I can see that fluctuates is RPM and "engine". I don't really know what "engine" is, but I suspect that is the problem, and is somehow causing RPM to fluctuate as well. Thoughts?

I am also going out now with some det cans and I will try to get another log, though I don't suspect it will be much different.

you have a ton of MAPdot noise. your accel/decel enrichments are going crazy.

what firmware are you on? where is your map line to the MS connected? what are your lag factor settings at?

I'm on the Alpha10 firmware from last summer, my MAP line is T'd off the cruise control line, and I'm not sure what my lag factor settings are, I don't know where to find those.

you need to get on the latest beta20. it has insanely improved noise filters for MAP and TPS.

What are you using for lag factors brain?

I think im in the 50s for everything still.

I was seeing around 50-60 TPSdot at idle at the same lag factor, with the new firmware, I see 4.


but 50 on this firmware is like 0 on the older ones. (where 0 is the most filtering)

with the beta firmwares, you can run 99 lag factors... not 50.

i thought it was the other way around. or are you saying you dont need any lag factor?

I will install the beta20 firmware this week and see if that fixes it. What will I have to re-tune after the update? Idle? VVT? Accel enrich?

there's a bunch of new idle code stuff that you can turn on (base duty table, voltage correction table, timing correction table). I just upgraded from alpha11, but I dont have VVT, where I know there were improvements there too but I just loaded my alpha11 map and turned on/tuned all the idle features.

BUT IIRc, alpha10 had different PID code, so you might have to retune those values...is your idle code PID parameters in the low double digits or the triple?

Idle PID are 25, 30, and 0.

So I'll update to Beta20 this week, but I am still skeptical that that will fix my problem, since I was running Alpha10 last year and didn't have this problem. I did move where my map signal is coming from... it was t'd off the cruise line right by the manifold last year, now it's T'd much closer to the cruise solenoid... would that cause this?

tee off the fuel rail vacuum line, that one isnt noisy; the ones off the TB are.

Oh, I found my lag factors.

MAP 50
RPM 50
TPS 30
Lambda 60
Coolant, MAT, Battery 50

I don't remember a vac line for the fuel rail, but I'll look. The one I'm using is off the back of the IM, at the top.

there's a comprehensive change log so you know what to change from alpha 10 to beta 20. you'll want to get beta 21 as soon as it is out too but the changes are minor from 20 (just dont run negative enrichments in your "new" throttle pump AE).

lag factor of 100 is basically no filtering. with the new code you can almost run that. it's pretty awesome and responsive.

under accel wizard, screen shot that for me.