ITB tuning help.

[JB83]

I have been working with and trying to understand ITB mode for several weeks (have watched Andy's ITB video many times and it has helped considerably however I am still missing something).
I can get the motor to run well below the 90% switch point and then not well above the switch point.
Attached is my Recent MSQ and a small datalog.
During mid range RPM and a throttle stomp the motor falls on its face and drops RPM.

you will noticed I have acceleration enrichment turned off, that was purposeful in trying to eliminate possible interferences.

Motor is a Miata 1.6. Throttle bodies are Jenvey 42mm. still have the stock exhaust. Running COP wasted spark and semi sequential fueling. system is a MS3 gold box, TS MS Ultra V3.0.28

also: is there a table with definitions for each function. Example: MAP - Manifold absolute pressure , the pressure in the intake manifold which is available for the intake stroke. Items like MAP are well defined in the literature but items like: PW, Duty cycle, ITB Fuel Load, Fuel Load, and many others I seem to be guessing at how they are directly relate to other functions. I spent a week playing with a fuel VE chart before I realized that the tie to fuel load was not linked to MAP like I was thinking. Clearly Im a new b and have a ton to learn.

Thank you

Jason

[2swe]

did you read the manual ?
is your AFR reading correct ?
do you tune it yourself, or are you using VEAL ?
any reason why you don't use EGO correction ? in this state of tune I'd allow 20% authority and 2%step size..

the reason why engine "falls on its face" is because it goes either full lean or full rich, nothing in between, except idle.

[JB83]

I read the 181 page manual 2 times before starting and then referred to it several times during the install

Then as I started to run the motor I found an additional manual to read. I have read much of that 300+ page manual regarding individual items like ITB but this manual seems to have missing references such as on page 98 of 335 section 8.11 ITB load settings there is a section that says (see Section Error: Reference source not found. of this guide) So there is reference material missing or lacking a pointer in the text (this is common in the text).

Which manual have you found to be the most helpful? Megasquirt-3: TunerStudio MS lite Reference Guide (comes up from help menu in TS 335 pages); MS3_Gold_Hardware-1.4-2016-05-18 (came with my MS3 181 pages); or is there another? I've read both and multiple times on the shorter. In no way would I claim that I gathered all of the information available.

"AFR reading correct?" I don't have a direct method to verify this. The sensor has been through its calibration, the plugs are not a fantastic color but are not fouling (they are a little on the dark side), the exhaust is rich during some of the run. This is an area that I have considered a weak point and if the problems persist or there is no direct help from this forum then I will change out the sensor with an alternate.

"do you tune it yourself, or are you using VEAL?" Both. I have used VE Analyze Live and have some earlier larger data logs that I was using to make some manual adjustments. These early data logs also helped me solve a few of the earlier problems with RPM sync so the log I submitted is the most recent and is small.

"any reason why you don't use EGO correction?" 2 very reliable sources (Andy Whittle and Jesse Prather) both suggest that authority should not be set above 5% once you have a reliable tune. Andy in his ITB tune video says when generating a data log for the VE table you should turn off EGO correction so you can record what your base tune is doing. This is why EGO correction is Off in the msq. When driving and using VEAL EGO correction has been set to simple or PID.

Thanks for your help. Any other suggestions?

[2swe]

when you power up your wide band with engine not running, it reads 22.3 right ? so when you see 22.3 in your datalog or dash gauge, you know for certain the engine is running full lean. so I'd say, AFR reading is correct.

5% EGO correction authority is good once you have finished your tuning, it's not your case at the moment, running open loop with your state of tune si sure way to ruin the engine.

VEAL, as far as I know, works with EGOcor ON, so there is no reason to switch it off.
if you wanted to tune it yourself using datalogs, turn EGOcor ON (20% authority, 2%step size) you will se what's your base tune doing, just watch the EGOcor (gauge and datalog field)
in MLV go to scatter polts , X axis RPM, Y axis Load, Z axis EGOcor. Add fuel where the scatter plot is red, remove fuel where it is blue, once you scatter plot is mostly green you can reduce EGO authority or turn it off and fine tune. start with low load and RPM, increase load and RPM gradually.

why is your idle so high ? wild cams ? are your throttle bodies properly synchronized ?
I'd try to smooth the MAP reading , because the MAP oscillation upsets the FuelLoad calculation and probably leads to wild AFR during idle.
my engine 1.8 16v with 46mm throttle bodies idles within 0.3 AFR

[JB83]

right on. Changed fueling today and made considerable improvement.

Yes VEAL works with EGO cor on.

Idle is just high because I haven't worried about it yet. No radical cams in this one.

Tomorrow I will run the car using your parameters.

Thanks for your help.

[440roadrunner]

I read the 181 page manual 2 times ...................... I found an additional manual to read. I have read much of that 300+ page manual regarding individual items like ITB but this manual seems to have missing references ...........

I'm interested in this, which manuals are you referring to? Thanks

[Yves]

a word of advice (mistakes I've made) : in the beginning it's easy to get overwelmed by the things to adjust and most jump right into it trying to adjust too much at once.

Try to get your engine to idle good and at proper rpm. Note the map/load where it runs during idle and work from there to adjust your ve table to what seems reasonable. Set your ignition timing accordingly and to reasonable values.
Lock out the area around your idle load in veal.

Set ego to on and use plenty of authority so the ecu can make corrections (like 50% or so). Drive around with veal and keep rpms low and avoid too much throttle input. Work on the transient loads. Save the tune that veal gives you. Review your logs and note what doesn't look good and go back to test driving touching the areas that didn't look good. Progressively go to more load/rpm.

Oh and maybe set AE to a value that it doesn't interfere...

[JB83]

@ 440Roadrunner
the manuals I've been through: the 181 pages that you can download from megasquirt for the MS3 gold box (the first few pages say if you are new to this type of efi control you need to read the manual before you start any type of install so in an effort to avoid simple mistakes I read it through a couple times, still made several simple mistakes). Then once I received the MS3 there was a memory stick that came with another 335 (or something like that) pages. this second manual interfaces with Tuner studio meaning when I click on a help topic the software jumps me to a page in the second manual.

did that answer your interest? You can find both manuals at https://www.efisource.com/docs/MS3_Gold ... -05-18.pdf and the second is Megasquirt3_TunerStudio_MS_Lite_Reference-1.5pdf.

[JB83]

@ Yves

That is very good advice.

I followed much of your logic by starting with the low load VE settings.

What I think I was doing wrong........ This car is a dedicated track car (unlicensed) so I was running it around our company shop, I think that the runs (about 300 ' N-S x 100' E-W) were far too short for the ARF to settle.
Last weekend I took it to a very remote area with a dead end road and was able to run long pulls. VEAL did a nice job bringing in the fueling so I could start to collect better data.

after about 30 minutes the VE table was refined much better and the car is running fantastic. Now I can collect data and just make some small changes.


thanks!!

[Yves]

@ Yves

That is very good advice.

I followed much of your logic by starting with the low load VE settings.

What I think I was doing wrong........ This car is a dedicated track car (unlicensed) so I was running it around our company shop, I think that the runs (about 300 ' N-S x 100' E-W) were far too short for the ARF to settle.
Last weekend I took it to a very remote area with a dead end road and was able to run long pulls. VEAL did a nice job bringing in the fueling so I could start to collect better data.

after about 30 minutes the VE table was refined much better and the car is running fantastic. Now I can collect data and just make some small changes.


thanks!!

Happy to hear it's working out.

Yes, you need longer runs to get veal to sort out the table.
Remember that VEAL is good to rough in the table, but you might have to make adjustments based on the things you see in the logs eventually. Keep using it to get the table close and then move to your own corrections based on the logs.
Also AE can be difficult to tune especially with ITB's. I haven't figured that one out myself.

[SteinOnkel]

@ Yves

That is very good advice.

I followed much of your logic by starting with the low load VE settings.

What I think I was doing wrong........ This car is a dedicated track car (unlicensed) so I was running it around our company shop, I think that the runs (about 300 ' N-S x 100' E-W) were far too short for the ARF to settle.
Last weekend I took it to a very remote area with a dead end road and was able to run long pulls. VEAL did a nice job bringing in the fueling so I could start to collect better data.

after about 30 minutes the VE table was refined much better and the car is running fantastic. Now I can collect data and just make some small changes.


thanks!!

Happy to hear it's working out.

Yes, you need longer runs to get veal to sort out the table.
Remember that VEAL is good to rough in the table, but you might have to make adjustments based on the things you see in the logs eventually. Keep using it to get the table close and then move to your own corrections based on the logs.
Also AE can be difficult to tune especially with ITB's. I haven't figured that one out myself.

That makes the two of us!

I have mine set to come on at a TPSDOT of 10. Anything less than that and the throttle response is absolutely nothing off idle and then everything at once.

Have been messing with the low speed drive ability for the past...oh...three months now. I can do it it's just that anyone else drives the car and they're like "My word that is a sensitive throttle."

What do you have your AE set to?