FIXED: Forcemotor control

'Microsquirt' Transmission Control development and support.

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kikkegek
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FIXED: Forcemotor control

Post by kikkegek »

I have a 4L80E and Microsquirt controller with 1.0.3BETA firmware

what Id like to know is if the forcemotorcontrol that is in the settings controls the linepressure like in the table below?

so I can adjust linepressure based on load in the setting from 0% to 100% linepressure. I know its inverted, so does 0% linepressore correspond to .98A forcemotor current? and does 100% linepressure correspond to .02A forcemotor current?
forcemotor control
forcemotor control
Forcemotor_table.png (19.16 KiB) Viewed 3529 times
I'd like to know that, because I cant seem to be able to drop my linepressure below 100psi. I tried that using the TEST MODE in Tunerstudio, but linepressure does not drop below 100psi in my case and just drops to 0 psi when I go from 1% to 0%. it does rise when I increase it from 10% up to 50% from 100psi to about 150psi, but never really drops below 90-100psi.
Attachments
currenttune.msq
current tune
(30.34 KiB) Downloaded 130 times
Last edited by kikkegek on Wed May 02, 2018 10:48 pm, edited 1 time in total.
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jsmcortina
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Re: Forcemotor control

Post by jsmcortina »

The Microsquirt cannot control current directly, it uses (open-loop) PWM.
At 1% line pressure commanded it will be at 99% PWM output duty which is likely around 3-4A from memory.

James
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kikkegek
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Re: Forcemotor control

Post by kikkegek »

jsmcortina wrote:The Microsquirt cannot control current directly, it uses (open-loop) PWM.
At 1% line pressure commanded it will be at 99% PWM output duty which is likely around 3-4A from memory.

James
Hi James, thanks for the quick reply. So if the current is 3-4A at 1%, which is well above the .98A from this table, then my linepressure should drop well below 100psi.

any ideas why my line pressure will not drop below 100psi untill 1% and just go to ZERO then I adjust it to 0%?
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jsmcortina
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Re: Forcemotor control

Post by jsmcortina »

I've not seen this reported as a problem before, so perhaps there's something hydraulically wrong with your gearbox?

Maybe trying measuring the actual current with a meter?

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
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kikkegek
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Re: Forcemotor control

Post by kikkegek »

jsmcortina wrote:I've not seen this reported as a problem before, so perhaps there's something hydraulically wrong with your gearbox?

Maybe trying measuring the actual current with a meter?

James
thanks, but I'd like to know first what is normal? I have ZERO experience with this 4L80E transmission, so learning from doing.

so, should my linepressure drop when lowering the linepressure percentage in TEST MODE like in the table above? is that normal operation?
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Re: Forcemotor control

Post by jsmcortina »

kikkegek wrote:so, should my linepressure drop when lowering the linepressure percentage in TEST MODE like in the table above? is that normal operation?
Absolutely, testmode should alter the line pressure. You probably need to be in-gear though, so put the car on stands and apply the handbrake.

James
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My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
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4L80E: force motor and line pressure control problem?

Post by kikkegek »

hi everybody. Im still chasing the hard 1-2 and 3-4 shift problem, while 2-3 shift is sweet as butter.

I have a 4L80E and running the Trans control release pre-1.0.2 beta3 firmware with a Microsquirt V3

So I have hooked up a oil pressure gauge to the test port and did some tests today.
live pressure gauge
live pressure gauge
linepressuregauge.jpg (115.43 KiB) Viewed 3492 times
first I put TS in TEST MODE and checked the line pressure against the set percentage:

https://youtu.be/CqqedwnKVdw

some really weird shudder starts when I drop line pressure below 20%. And there seems to be only a very small bandwith within I can control line pressure. only below 20% setting the line pressure starts to drop????? and the shudder also starts

Then I hooked up an amp clamp to read the current at severals percentages:

https://youtu.be/5DHIHF6YVnw

at about 60% setting I already have 0 amps, which should result in maxium line pressure under normal control.

I checked if changing the frequency of the EPC from 590 to 290Hz made a difference, but makes absolutely no difference in the readings I took at 590Hz.

I have double checked wiring, grounds, but all seems fine.

Anybody have any ideas...why I dont seem to have normal line pressure control?
Attachments
2018-01-06_21.24.37.msq
current tune
(30.35 KiB) Downloaded 96 times
my project page, BBC 454 with LPG vapour injection:
my BBC 454 LPG vapour injection tuning story 8)

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kikkegek
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Re: Forcemotor control

Post by kikkegek »

ran some test, but in P

http://www.msextra.com/forums/viewtopic ... 38&t=68074

I'll run the tests tomorrow again but in D to see if it makes a difference.
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redrider2911
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Re: Forcemotor control

Post by redrider2911 »

Isn’t the line pressure on the GM transmission controlled by the EPC solenoid acting on the boost circuit which in turn raises the line pressure by pushing the pressure regulator further out of balance?... so can’t you never get less line pressure than what your pressure regulator spring is setup with??... or am i understanding that wrong?
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Re: Forcemotor control

Post by kikkegek »

I dont have that kind of knowledge of my transmission (yet).

I am just chasing the hard 1-2 and 3-4 shift en troubleshooting the stuff I found by doing these tests.

the shudders at low percentage setting dont seem normal/good for my transmission...it shakes really bad at 13% (check the video).

and the current control also dont seem right...since I have zero amps at 50-60% line pressure setting...that should be at WOT=100% line pressure....correct?

right know its kicking me in the back like a mule on the 1-2 shift when I step hard on the throttle...and even at light thorttle the shifts are far to hard compared to the buttersweet 2-3 shift it does
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LAV1000
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Re: Forcemotor control

Post by LAV1000 »

Any knowledge on how the OEM forcemotor is amp controled ?
Does it use PWM'ed current or a constant current ?
Might explain the ratling in low amps (PWM'ed)
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Re: 4L80E: force motor and line pressure control problem?

Post by jsmcortina »

According to the GM Technicians Guide I have, the line pressure should be 90psi at 0A current and 0psi at 1A
But also it says
Duty 5% = 0.1A = max line pressure
Duty 40% = 1.1A = minimum line pressure

The 40% appears corresponds to the 60% number you are seeing as the trans firmware uses the number backwards so a larger number gives more pressure.

If the line pressure you see doesn't match up with these currents, it can only be an internal valve body or pump issue I think?

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
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kikkegek
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Re: 4L80E: force motor and line pressure control problem?

Post by kikkegek »

jsmcortina wrote:According to the GM Technicians Guide I have, the line pressure should be 90psi at 0A current and 0psi at 1A
But also it says
Duty 5% = 0.1A = max line pressure
Duty 40% = 1.1A = minimum line pressure

The 40% appears corresponds to the 60% number you are seeing as the trans firmware uses the number backwards so a larger number gives more pressure.

If the line pressure you see doesn't match up with these currents, it can only be an internal valve body or pump issue I think?

James
he thanks James, makes sense.

So I get these values in test mode:

5% - 0,45A
10% - 0,45A
17% - 0,60A
30% - 0,27A
40% - 0,20A
50% - 0,10A
60% - 0,03A
70% - 0,0A

so dont really seems to peak at 17%, but drops at high and lower values? Ill do this test again today. because from 17-20% and lower values I also get the shaking transmission.

question though:
why can does TS allow for 0-100% settings, when the control of line pressure from your information is within a smaller range?
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ashford
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Re: 4L80E: force motor and line pressure control problem?

Post by ashford »

kikkegek wrote: 5% - 0,45A
10% - 0,45A
17% - 0,60A
30% - 0,27A
40% - 0,20A
50% - 0,10A
60% - 0,03A
70% - 0,0A

so dont really seems to peak at 17%, but drops at high and lower values? Ill do this test again today. because from 17-20% and lower values I also get the shaking transmission.

question though:
why can does TS allow for 0-100% settings, when the control of line pressure from your information is within a smaller range?
this code isnt just for 4l80, different solenoids have different impedance, for example the 4r70 has 3 different impedance epc solenoids the latest was high impedance and has a control range for me of 20-80%. also you can add a resistor inline with it to widen the window, i have done this to the 4l80 install i did as it works much better.

with the information you have posted it leads me to believe there are 2 possible modes of failure.
1. amperage readings are inaccurate and there is a hydraulic issue
2. wiring/solenod issue or failing/self protecting transistor in microsquirt

for #1 amp clamp style ampmeter are very inacurate at lower currents. there is a trick to this wrap the wire around the clamp 10 times in a coil so that the wire passes through the center 10 times an you will have a reading 10 times higher. also being that this is a pwm signal on an inductor this can do funny things. you might be able to get a more accurate reading in ac mode so long as you are in the 30-70% range. when doing an actual test it would probably be be best to do a dc reading on the switched power side with no flyback. with flyback it woul be best beteen transisot and flyback.

if that checks out fine i would then unplug the us find its pressure solenoid wire , put a jumper in it and ground it. if it has the same readings as when testmode has 0% there is a wiring problem from us to solenoid or solenoid. if it is different ther is a problem with the us, ground, horrible flyback, transistor or it is self protecting
kikkegek
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Re: 4L80E: force motor and line pressure control problem?

Post by kikkegek »

Thanks man. I'll recheck that.

What size and type resistor would you use?
if that checks out fine i would then unplug the us find its pressure solenoid wire , put a jumper in it and ground it. if it has the same readings as when testmode has 0% there is a wiring problem from us to solenoid or solenoid. if it is different ther is a problem with the us, ground, horrible flyback, transistor or it is self protecting
I don't understand this piece.

-What's the "us"?
- where goes the jumper?
- what and where do I measure?
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ashford
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Re: 4L80E: force motor and line pressure control problem?

Post by ashford »

kikkegek wrote:Thanks man. I'll recheck that.

What size and type resistor would you use?
probably a 2-5 ohm 50watt resistor


I don't understand this piece.

-What's the "us"?
acronym for microsquirt i don't know the key stroke for µ so i use u.where ms would be megasquirt
- where goes the jumper?
to ground so simulate the fet being full "on"
- what and where do I measure?
same place you have been
kikkegek
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Re: Forcemotor control

Post by kikkegek »

LAV1000 wrote:Any knowledge on how the OEM forcemotor is amp controled ?
Does it use PWM'ed current or a constant current ?
Might explain the ratling in low amps (PWM'ed)
is also uses a duty cycle I guess, since you can choose 590 or 290Hz for the force motor in the settings menu in TS
my project page, BBC 454 with LPG vapour injection:
my BBC 454 LPG vapour injection tuning story 8)

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redrider2911
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Re: Forcemotor control

Post by redrider2911 »

redrider2911 wrote:Isn’t the line pressure on the GM transmission controlled by the EPC solenoid acting on the boost circuit which in turn raises the line pressure by pushing the pressure regulator further out of balance?... so can’t you never get less line pressure than what your pressure regulator spring is setup with??... or am i understanding that wrong?
Ok. I have to apologize. While your transmission does have a boost valve that the EPC acts on and that acts on the pressure regulator, it does not have a preload spring like mine that sets a base pressure value; it only has a little balance type spring. So it does appear you should be able to take that line pressure down to almost 0.

What i would look into though is maybe a stuck boost valve... if it is not seating all the way back in it’s bore, then that would make it impossible to lower the line pressure all the way. Though that might not answer your weird amperage readings...
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Re: Forcemotor control

Post by kikkegek »

Thanks for getting back. Still the all gears would shift hard and I only have hard shifting in 1-2 and 3-4. 2-3 is just fine
my project page, BBC 454 with LPG vapour injection:
my BBC 454 LPG vapour injection tuning story 8)

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My 1977 GMC C15 Suburban "Storm" 8)
kikkegek
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Re: Forcemotor control

Post by kikkegek »

I checked and cleaned up the trans connector hoping to find a bad connection and ran the current test again

0% - 3,0A
1% - 0,70A
2% - 0,60A
5% - 0,45A
10% - 0,45A
16% - 0,70A
17% - 0,60A
30% - 0,27A
40% - 0,20A
50% - 0,10A
60% - 0,03A
70% - 0,0A

so in the end it ramps up again, but strang how it rises to about 16%, then drops back and finaly rises within 2% to 3,0Amps

guess thats why I dont have a line pressure below 100psi...could explain why my 1-2 and 3-4 is hard shifting, even at low loads....but still strange that my 2-3 shift is smooth.

really scratching my head here
my project page, BBC 454 with LPG vapour injection:
my BBC 454 LPG vapour injection tuning story 8)

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