Inconsistent AFR behavior issue

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dbyrd
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Joined: Sat Jan 27, 2018 2:34 pm
Location: Franklin, GA

Inconsistent AFR behavior issue

Post by dbyrd »

Have an odd issue I have been investing for the past two weeks or so.

The AFR goes lean under certain situations without an obvious reason that I can see. For example it can happen sometimes when clicking burn in TunerStudio 3.0.28. Also experience sometimes just restarting the motor (ie cycling ecu). I have been using AutoTune to adjust the VE table and overall it has been working well. But when the AFR goes lean the VE tries to adjust accordingly. For example normal idle is in the 55-58 range on the VE table. However, when things go haywire I see the values to up into the 90s.

The odd thing is I can get get the AFR back in normal range 14-15 by cranking up the cell value in the VE able. Then sometimes if I click burn it suddenly goes rich in the 11-12 range. Then I get the AFR back to normal by adjusting the cells back to the mid to upper 50s.

Have been reading through the forms and elsewhere looking for others that have run into this. Did find something similar where there was a reference to the barometric value getting adjusted during a ecu reset/save causing the fuel correction to go screwy. To address this possibility I set the upper and lower limited around the standard kPA for my area. No real change to the behavior.

Also was concerned that I could be running into a cavitation issue with the fuel pump due to the Fram G3 pre-filter I had installed causing fuel pressure fluctuations. Replaced it was a Holley 100 micro pre-filter and this does seem to be better. Had noticed a bit of noise coming from the pump prior. Still experiencing the issues with the AFR.

I do have close loop idle setup in the current tune, but had the motor idling consistently on open-loop before (when the AFR wasn't screwy).

With the inconsistent behavior of the AFR haven't been about to run the WUE AutoTune. Sometimes when I start the engine all is fine, but sometimes it shows lean.

A bit of info about the install..

Suzuki Samurai 1.3L 4cyl. Newly rebuilt motor with a few thousand miles on it. It originally had Weber 32/36 DGEV on it that didn't never really run all that well and terrible cold weather starting.

For the past two months have converted over to a GM TBI 700 (single barrel) and new GM sensors (TPS, MAP, CLT, MAT). Replaced the Injector with a new Standard TJ14 which is an OEM replacement for the factory GM/Delphi part (GM# 17111986 / Delphi# FJ10041). These are low impedance injectors and I installed a 100watt 7.5 ohm resistor inline. Wideband Bosch 4.9 O2 with 14point7 Spartan 2 OEM controller. The Spartan 2 is powered off the Fuel pump relay with sensor ground connected to same location as MS (and IAC stepper controller). O2 heater ground is connected to the chassis. Running a MicroSquirt with msextra 3.4.2.

For those not familiar with the Spartan 2. It produces two calibration AFRs of 13.3 and 16.6 during startup. These can be seen in the datalogs.

Current tune file and two data logs attached. Datalogs are zipped due to size.
2018-01-27_17.54.35_Sami_AFR_Issue.msq
Current tune file
(115.8 KiB) Downloaded 33 times
Here is an example. Datalog from engine start.. Goes lean. Then I adjusted the VE table to bring back in line to "normal". Prior day to this had driven the car for 30+ minutes with idle AFR in the 14.5-14.8 range.
2018-01-27_16.24.23.msl.zip
AFR Goes Lean. Then adjust the VE table to bring back in line.
(102.83 KiB) Downloaded 34 times
Datalog from engine start from previous one. Just shut off engine and restarted it. AFR went lean again.
2018-01-27_16.28.24.msl.zip
Data log after restart
(28.46 KiB) Downloaded 25 times
Any suggestions welcome.

David
dbyrd
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Posts: 16
Joined: Sat Jan 27, 2018 2:34 pm
Location: Franklin, GA

Re: Inconsistent AFR behavior issue

Post by dbyrd »

Have been doing further testing this afternoon. Narrowed it down in the datalog to a burn event triggering the AFR going lean @ 96.993s. Looking at the MLV trace I see status1 go from 8 to 9 then to 8. Looking in the msextra 3.4.2 source code (ms2_extra_vars.h) this is the "Needs Burn" bit along with Sync OK.

Code: Select all

#define STATUS1_NEEDBURN    1   // need burn
#define STATUS1_LOSTDATA    2  // lost data
#define status1_conferr     4    // config error
#define STATUS1_SYNCOK      8


I also disabled the EGO correction to rule it out tweaking things. Didn't mention this in the previous post, but the MS is running in Fuel Only configuration.

Engine was warmed up fully and idling along at an avg AFR of 14.6. Then on the Tune Analyze Live tab increased the VE table by 1. Clicked Save to ECU. AFR indication went full lean. As mentioned before I have seen similar behavior sometimes when burning other changes with the motor running. Haven't found any specific pattern. Also have seen it go full lean (19.6) immediately from a new engine start as I posted the datalog for previously.

The MAP and PW didn't change. The idle RPMs dropped approx 40 after the AFR went lean. Based upon previous experience I can crank up the VE table idle cells (90s) to bring the AFR back in line. Occasionally I see it then go very rich until I set the VE table idle cells back to the original value.

Seems that something goes off the rails. Hopefully others more familiar with the data logs can see more than I can.

Any thoughts?

Attached is new msq and msl file.
2018-01-29_19.38.15_Sami_AFR_Issue2.msq
Current msq file
(115.8 KiB) Downloaded 32 times
2018-01-29_18.32.02.msl
Datalog with two engine starts. Second has a ecu burn event sending AFR to lean
(673.11 KiB) Downloaded 30 times
BlackBird_SR71
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

1: Raise EGO minimum RPM to 1,300. Idle values can often be made more stable buy tuning manually in Open Loop and filtering out EGO control and Auto-Tune.

2: Lock out the idle Cell values by right clicking while in Auto Tune VE Table. Select a 3 x 3 square of Cells around the idle speed. Cell values are calculated by averaging Cell areas in the surrounding cells. Cell " weighting " .

3: Manually set idle Cell values by lowest KPA reading ( highest Vacuum in/hg ) and highest and smoothest idle RPM.

TBI best idle will be around 13.6 to 13.8. 14.7 is way too lean for anything but Full Sequential Port injection.

You VE table is a mess. Has a lot of Valeys and Peaks. Thta's usually not goodUse Google to find your engines factory stock HP and Torque measurements. Enter those figures in the VE Table Generator to get a Baseline VE table. Auto Tune will correct based on that Baseline table. Incorrect values in entered in VE table generator will create a mess.

Edit: Your Cell values between 25 KPA to 45 KPA vary way too much. This will make idle unstable and then the EGO correction will try and fix things. It will end up oscillating. The Values between 800 to 1,500 RPM and 20 to 45KPA should all be very close. You should replace the 15 KPA row with 20 KPA. 15 is too low. The values from idle to 1,500 RPM vary too much as well, and this may affect Cell weighting.
BlackBird_SR71
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

Full Lean after a Burn, while the engine is running is quite common. Certain tables are only meant to be Burned with the engine not running. That is because the Values are held in a Buffer on your laptop until you permanently " Burn " them to the ECU. You will get a Hiccup or even an engine stall when you do this. MS specifically warns you several times in the Hardware Manual not to do this with the engine running.

When you get this Hiccup, the O2 sensor momentarily experiences a Reset. So it goes into warm up mode. This normally shows Full Lean on your MS AFR gauge until the O2 heater cycle time is completed.

Try using the VE Table in Auto Tune instead of the main VE table when altering values. Use the Save to ECU button. I believe that the write function to the controller is a bit different, and you shouldn't get that Hiccup and Reset of O2 heater.
Last edited by BlackBird_SR71 on Sat Feb 03, 2018 4:06 am, edited 2 times in total.
BlackBird_SR71
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

Give me the year and model of the Samuri engine and any modifications. I'll see if I can come up with a better baseline VE table.
BlackBird_SR71
Experienced MS/Extra'er
Posts: 354
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

Your Default Baro settings are also incorrect. They should be 105, 80, 100
BlackBird_SR71
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Posts: 354
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

Quickly whipped up a Baseline Tune for you based on 1992 Samuri 1.3 stock specs. 69 HP at 6,000 RPM and 75 ft/lbs Torque at 5,600 rpm.

You may want to give this a try. You should re-calibrate all sensors just as a Double Chcek.

Made changes to:

1: EGO control minimum RPM to 1,300. EGO control should not be in closed Loop at idle . Especially not with an IAC valve. Can cause oscillations on Initial Tuning.

2: EGO Controller Authority = 10%

3: Locked out Idle Cells in Auto Tune. Tune Cell values for idle manually, using best Vacuum ( Lowest KPA ) bests idle method. Adjust cells in a 3 x 3 square. Note: Disable IAC valve while setting Idle manually.

4: Changed AE settings to a basic Accelerator Pump style. Disabled Wall Wetting for now. Overly complicated method. 100 percent TPS Dot will work well and is simple to Tune

5: Minor changes to Cranking Enrichment. Lowered cranking RPM point to 450 RPM . 650 was too high

6: Minor revisions to WUE . 150 F and above to 100% line.

7: Entered correct stock HP and Torque specs for Ve Table generator. Much better looking VE table.

8: Fixed incorrect Baro setting. Set to TS defaults now.
Samuri Tune CM #1.msq
(118.86 KiB) Downloaded 35 times
dbyrd
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Posts: 16
Joined: Sat Jan 27, 2018 2:34 pm
Location: Franklin, GA

Re: Inconsistent AFR behavior issue

Post by dbyrd »

BlackBird_SR71,

Great. Appreciate your time looking at this. Very helpful. Will give it a shot this evening.

I have some older msq files from extended idle/drive autotune sessions before I started doing testing that I can compare against as well. The VE table in the posted msq was screwy since it had been just barely been tweaked from a baseline AFR/VE table regenerate using similar stock values I pulled off the net. Had done this during my troubleshooting of the AFR behavior.

I have tried to be careful about burns/saves while the engine was running. Feels that I have read the manuals so many times over the past 2 months since I started this adventure I can recite them in my sleep at times.

David
BlackBird_SR71
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

It can be a very steep learning curve. Once you get some of the features figured out it all starts to fall in place. But having a VE table that is close to begin with definitely helps.

PM sent.
BlackBird_SR71
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

dbyrd wrote:BlackBird_SR71,

Great. Appreciate your time looking at this. Very helpful. Will give it a shot this evening.

I have some older msq files from extended idle/drive autotune sessions before I started doing testing that I can compare against as well. The VE table in the posted msq was screwy since it had been just barely been tweaked from a baseline AFR/VE table regenerate using similar stock values I pulled off the net. Had done this during my troubleshooting of the AFR behavior.

I have tried to be careful about burns/saves while the engine was running. Feels that I have read the manuals so many times over the past 2 months since I started this adventure I can recite them in my sleep at times.

David
There is a very handy little MS plug-in to add a " Kill " button. Comes in very handy for those times you have to do a Power Cycle and switch off the ignition. Eliminates that warning about losing settings because you just switched the Power off before Burning. How the heck are you supposed to Cycle the Power without switching the ignition off?

Well this plug-in from SymTechLabs solves that. Sets the Req-Fuel to zero. Engine dies. Power is still on. After a few seconds delay, it restores the Req-Fuel settings to their previous. With the engine not rotating. Burn your settings, then restart the engine. Bingo. Problem solved.

Thread link:

http://www.msextra.com/forums/viewtopic ... 01&t=47287

Also comes in handy for Remote Tuners like me who may see a problem and want to " Kill " the engine quickly.

Download link:

http://www.symtechlabs.com/support/know ... switch.jar
dbyrd
MS/Extra Newbie
Posts: 16
Joined: Sat Jan 27, 2018 2:34 pm
Location: Franklin, GA

Re: Inconsistent AFR behavior issue

Post by dbyrd »

Will give it a shot tomorrow. Didn't get much of a chance to test more this evening.

Had not seen this plugin before. I can see where it would be very handy. Seems like something that would be a useful sticky post.

For the sake of others looking at this thread as we exchanged via PM here are my test results from last night based upon your msq file.
I integrated your msq file with one of my earlier ones from when I was driving the car a bit to autotune it. Did pull up the entire VE table so the idle cells were in the mid 50s. Could of tweaked the required fuel as well based upon some playing I had done before.

Did experience the AFR lean issue again during one of the restarts tonight. Shut off the motor and started it back up then AFR back to normal. No other changes. Have an oscilloscope that I will hook up to the injector tomorrow after work and see if it happens again to get a reading from normal and lean AFR indications.
2018-01-30_21.29.11_Sami_Test_based_on_SR71.msq
Latest tune file
(115.71 KiB) Downloaded 29 times
David
dbyrd
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Posts: 16
Joined: Sat Jan 27, 2018 2:34 pm
Location: Franklin, GA

Re: Inconsistent AFR behavior issue

Post by dbyrd »

You weren't kidding about the button. A nice big Kill button.
Screen Shot 2018-01-31 at 9.39.57 PM.png
Screen Shot 2018-01-31 at 9.39.57 PM.png (21.33 KiB) Viewed 1919 times
BlackBird_SR71
Experienced MS/Extra'er
Posts: 354
Joined: Tue Mar 22, 2016 2:26 pm

Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

Is the Lean restart consistant or random. You could be dealing with a heat soak issue on Hot Restarts?
Matt Cramer
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Re: Inconsistent AFR behavior issue

Post by Matt Cramer »

The latest MS3 firmware has a "kill" and "reset ECU" button as standard features under the output test modes.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
dbyrd
MS/Extra Newbie
Posts: 16
Joined: Sat Jan 27, 2018 2:34 pm
Location: Franklin, GA

Re: Inconsistent AFR behavior issue

Post by dbyrd »

Good question. Issue appears to be random based upon experience so far. The MAT sensor is attached to the bottom of an Edelbrock 1203 air filter (10").

Haven't seen the temps be out of the norm. When the AFR behavior happened the other night during a restart the MAT was around 80F. Hood was closed. Outside temp was in the 50s. I have seen the MAT temps up into the 110F-120F with the hood closed and extended idle/tuning times. CLT temp floats around 180F once engine warmed up.

David
dbyrd
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Posts: 16
Joined: Sat Jan 27, 2018 2:34 pm
Location: Franklin, GA

Re: Inconsistent AFR behavior issue

Post by dbyrd »

Matt,

Hum. I don't see those in TS with msextra 3.4.2 on my uS. Perhaps I am looking in the wrong place.
Screen Shot 2018-02-01 at 11.43.22 AM.png
Screen Shot 2018-02-01 at 11.43.22 AM.png (50.33 KiB) Viewed 1897 times
David
BlackBird_SR71
Experienced MS/Extra'er
Posts: 354
Joined: Tue Mar 22, 2016 2:26 pm

Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

dbyrd wrote:Matt,

Hum. I don't see those in TS with msextra 3.4.2 on my uS. Perhaps I am looking in the wrong place.
Screen Shot 2018-02-01 at 11.43.22 AM.png
David
The feature is only in MS3. The Plug-in works with MS1 and MS2.
dbyrd
MS/Extra Newbie
Posts: 16
Joined: Sat Jan 27, 2018 2:34 pm
Location: Franklin, GA

Re: Inconsistent AFR behavior issue

Post by dbyrd »

Had the AFR behavior issue happen again. This time wasn't during a ecu save. The AFR was sitting at 19.6 then I opened the Idle Control Dialog in Tuner Studio. This caused a dip in the RPM and MAP then the AFR went back down. Didn't save anything to the ECU.
2018-02-01_17.57.43.msl
Datalog from engine start
(468.7 KiB) Downloaded 25 times
Not following how opening a dialog in TunerStudio would impact the engine.
Screenshot of when I opened the Idle dialog
Screenshot of when I opened the Idle dialog
Screen Shot 2018-02-02 at 5.20.04 PM.png (76.68 KiB) Viewed 1863 times
To follow up on a previous posting.. I used an oscilloscope on the INJ1 circuit and the pulse width matches what I see in Tuner Studio. Don't have a current clamp at the moment to look at the amperage load during an injector pulse.

Seems odd that with the same PW, RPM and MAP the AFR would be such different levels. Have to think that either the O2 readings are off or the injector is not consistently delivering fuel even with the same PW. I have an email off to Alan (14Point7) to get his thoughts on the O2 side.
BlackBird_SR71
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

Could be a sticky injector. That won't show up on any electrical checks. Even a new injector can be faulty

An bad connection at the injector terminal would still show a good PW.
BlackBird_SR71
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Re: Inconsistent AFR behavior issue

Post by BlackBird_SR71 »

Had a good long look at your Datalog ( At 2:30 AM when I do my best thinking ) . I think you are seeing an instrumentation error. Could be you are catching the O2 sensor in heat up mode or after a rest caused by a burn. And no the Burns aren't always consistant. Some will cause the " Hiccup " some won't. Did you notice my mention of this in Post #4? It's in Bold Red now.... LOL

From about 7 seconds through 25 seconds you see the AFR values ramp up. Peak occurs around 18 seconds. But you KPA values and RPM are very stable. There is no way an idle will remain that stable with the AFR varying like that. Unless it is actually not varying, and it's just the O2 sensor going through the warm up cycle.

The other thing I was thinking about was Wall Wetting. With a TBI manifold, heat soak could be evaporating the fuel off the Intake Manifold walls. That could cause a Lean condition during a warm or hot restart. TBI manifolds are much worse for this than Port Injection. Might be something to have a look at. Possibly extended ASE Taper may help
Last edited by BlackBird_SR71 on Sat Feb 03, 2018 4:11 am, edited 1 time in total.
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