4l80e build; output solenoid A and B issues

A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
Orion1800
Posts: 9
Joined: Sun Oct 16, 2016 4:16 pm

4l80e build; output solenoid A and B issues

Post by Orion1800 » Wed May 03, 2017 2:16 pm

I have completed my Megashift build and install, but the output solenoids are not working as expected. I have jacked up the car and tested the trans, and have in some instances felt it shift through all 4 gears. But when I get on the road, the shifts do not seem to correspond with the shift table. I confirmed that I am using the correct table. It would take an extra long time to shift into second, and then never go to third, and want to downshift prematurely into first. Ultimately when target gear changes the trans does not shift.

I checked my VSS signal and it does not seem to have noise or false readings. I tried re-flashing the code and resetting all the tunerstudio values. Now the car does not want to shift into first at all when I put it in drive. It stays in second no matter the gear level position. All the other I/O seems to be working as expected. One thing about the datalog is that I can't find the status of the 2 output solenoids in the log.

I confirmed that the solenoids in the trans are getting power, and that the solenoid resistance is in range (23 Ohms each). I don't know what is the next step in my troubleshooting process. I am wondering if somehow I burned out the TIP120 transistors on VB3 and VB4? I am not sure how to troubleshoot the circuit, or confirm that the processor is actually commanding the transistors to actuate.

Any advice is appreciated.

Rukavina
Posts: 47
Joined: Fri Aug 15, 2014 7:58 pm

Re: 4l80e build; output solenoid A and B issues

Post by Rukavina » Sat May 20, 2017 9:30 pm

Did you figure it out? I had just built another board and the way I tested my shift solenoid outputs was to open case so I could get to transistors, simulated a vss and shifted thru gears manually while using a test light on the center leg of transistor. One side of light to 12v and other to center leg.
Be careful not to touch processor side. I did this on truck with paddle shifter buttons" no jimstim". I do have a sine wave generator for vss signal. The rest of inputs I use vehicle. You can't test low current transistors with a light- too much current. You can make a led test light for those. Also check for signal to transistor pin on closest side to processor/header jumpers. That's a 5v signal from header....if I remember right

Orion1800
Posts: 9
Joined: Sun Oct 16, 2016 4:16 pm

Re: 4l80e build; output solenoid A and B issues

Post by Orion1800 » Tue May 23, 2017 9:19 am

Thanks for the reply. I have not had a chance to check it out yet, although I don't have a signal generator so any troubleshooting I'll be doing will be on the vehicle.

I was using a multimeter to check voltages and resistance in the legs of the transistor. I was careful to not touch multiple legs with my probe, but based on what you said about the test light I'm hoping I did not do any damage. So with everything powered up I should be seeing the following (correct?):
-constant 12 volts on the collector leg (coming from shift solenoids)
-ground at the emitter leg (when solenoid is off)
-5 volts on base leg when solenoid is actuated

I have read in several posts where people suspect their firmware is corrupted, how would I test for this issue? If I am successfully seeing the correct inputs, but these shift solenoid outputs are not right, should I be suspecting the firmware? As mentioned before, I tried re-flashing and have used several iterations of the 4.1XX code, but nothing has seemed to 'fix' the issue. Is there a very basic version of the code I should start out with, just to confirm the board and processor are working?

Rukavina
Posts: 47
Joined: Fri Aug 15, 2014 7:58 pm

Re: 4l80e build; output solenoid A and B issues

Post by Rukavina » Tue May 23, 2017 2:06 pm

Transistors switch negative/ground on and off. Power goes from "battery" thru the load "solenoid" and stops at transistor. Depending on signal it either stops or passes thru to ground. You test with a load from battery thru load "light" to transistor. One leg will have ground always and one will change state depending on signal. Signal is 5v going thru to ground

Rukavina
Posts: 47
Joined: Fri Aug 15, 2014 7:58 pm

Re: 4l80e build; output solenoid A and B issues

Post by Rukavina » Tue May 23, 2017 2:41 pm

Current code is v5.201. I have the gurus looking at the code for a canbus issue between tuner studio and hardware. As far as the rest of it ... it works. I spent today playing with my vss signal and I think I got it configured ok. Other than the new issue I had with the code crashing in ts when I opened vss page ( I don't think it has anything to do with gpio code itself, I used saved working code and downloaded again with same issue and problem started when ts upgraded) it has worked well for me for ~3 years. And the gear inputs from tranny are hydraulic pressure switches that tell what gear it's currently in, not the commanded target. So if you command 1st.... the solenoids change state, the spools move, the respective circuits pressurize and the switches make or break. Those are relayed to gpio. Those inputs monitor "after the fact" and indicate final status.
Your shift coils are changed by the shift table/vss/load or by manual paddle (if installed)

Orion1800
Posts: 9
Joined: Sun Oct 16, 2016 4:16 pm

Re: 4l80e build; output solenoid A and B issues

Post by Orion1800 » Tue May 23, 2017 4:10 pm

I too started having canbus issues between MS and GPIO through Tunerstudio. I'll be interested to see what the fix is there. For now I added a DB9 to the GPIO, so I can keep working with it. I'll plan on upgrading to the current 5.201 code and see if that helps. I'll also check the voltages on the transistors and post the results.

Rukavina
Posts: 47
Joined: Fri Aug 15, 2014 7:58 pm

Re: 4l80e build; output solenoid A and B issues

Post by Rukavina » Wed May 24, 2017 10:45 am

Right now I have no issue changing parameters directly to gpio. I didn't check this weekend about "monitor comms" but I have not had an issue with that. My only issue has been when I change vss settings and soon as it gives me the "settings require power cycle" message the code crashes. I have posts here and ms2/tuner studio forum about it. I have some good info on the 4l80e if interested

Orion1800
Posts: 9
Joined: Sun Oct 16, 2016 4:16 pm

Re: 4l80e build; output solenoid A and B issues

Post by Orion1800 » Tue Jun 06, 2017 11:30 am

OK, I did about the worst thing a person who is asking for advice can do, which is let the project sit for a while. But I finally was able to do some testing. Here's what I did:

-I checked the voltage at the transistors and found 12 volts on the outside legs, so presumably the wiring from the trans to the circuit board is good.
-I loaded the most recent code (5.202). I changed only the most basic settings to get the 4L80E inputs and outputs correct and of course the gear and axle ratios of the car. I left all other default settings as is.
-With the rear wheels on the jackstand I ran the car. I monitored the current gear, and noted that when it changed from 1-2, 2-3, and 3-4 I could feel the trans shifting.

Now my current problem. As stated before, the shifts did not at all correspond to the shift table. I have attached a data log of a quick 20 second test, basically putting it in drive and allowing it to shift through all 4 then come back down again. I watched the shift table as I did this, and all shifts were significantly delayed from where the table expected them to occur. So if is not shifting based on the table, what is dictating the timing of the shifts? I parsed the attached datalog and could not find any explanations. Maybe someone could provide some guidance if there's something obvious regarding the tuning that I'm clearly missing.

Last, I believe that the shift solenoid states appear as outputs 1 and 2 in the datalog. Am I correct on seeing this?
Attachments
2017-06-05_18.18.01.msl
(184.44 KiB) Downloaded 254 times

Rukavina
Posts: 47
Joined: Fri Aug 15, 2014 7:58 pm

Re: 4l80e build; output solenoid A and B issues

Post by Rukavina » Tue Jun 06, 2017 10:38 pm

On phone at the moment so...... if you know for a fact it is shifting I would check your tps/map table settings first. It blends a weighted map vs tps signal over tps I think. But it adjusts your final load for your table. Also ground your 2nd table wire or make table 2 identical to one just in case you are on wrong table. When I got a minute I will look at your msq

Rukavina
Posts: 47
Joined: Fri Aug 15, 2014 7:58 pm

Re: 4l80e build; output solenoid A and B issues

Post by Rukavina » Wed Jun 07, 2017 10:22 am

Hey can you also post your tune so I can look at your settings

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