4th Gear Slip under load

[thatswagenwagen]

Hi all,

I decided to start a new topic concerning slippage in my transmission under moderate load in 4th gear.

What boggles me is the PC% reports a random drop out to 0% upon acceleration, and my SP2% (4th gear apply solenoid) also begins to drop out to 0%. Could this be a Datalog/CANCOMM error, or is it possible that the solenoids are briefly closing and slipping the trans.

My shortened datalog is posted below focusing on one major slippage (sharp random RPM spike).

Be advised I am running V 4.145 linked to a MSII

Thanks,
Sam

[Bernard Fife]

tww,

.MSQ files are normally settings files, and .MSL are datalogs. Your second file is a datalog (with an incorrect file extension).

It appears that there is a series of comm errors. These are especially plausible if you are using the CANbus pass-through (connecting to the GPIO board through another controller such as MS3 or MS-II). You do appear to be using the CANbus pass-through (with MS3 or msextra it seems).

The reason I suspect comms errors is that in your datalog, many of the pressure control (PC%) spikes coincide with impossible manual gear (mGear) values (+76, -24, etc.) so this indicates that comms errors are very likely. auxCH and slip (the adjacent values to PC% in the outpc channel structure) are similarly affected, and this points strongly to CANbus issues scrambling the data rather than incorrect values being sent.

I couldn't say if this was an error due to interference on the CANbus physical connection, or an error from the way the engine ECU handles the CANbus pass-through (though I have never seen such errors when using B&G code to test the CANbus pass-through). If this was mine, I would check my CANbus physical connections very, very closely, and if that didn't help you might ask the msextra/MS3 developers to check the integrity of their pass-through capabilities.

FWIW, I don't think the actual PC% is being affected, it is just the reported values are corrupted after traversing the CANbus/serial path.

Lance.

[thatswagenwagen]

Lance,

Okay, thanks for that, It is a MSExtra on CANBUS so I will re-examine my wiring, I remember having a stripped wire close to the daughtercard...

It was just odd that the errors only existed when accelerating, I might hookup the LEDs to the solenoid-out wires again to check for 100% operation and see if they flicker at all.

The slip actually keeps me from speeding!

V5.093 looks really useful... oh well I'll report back my findings

Thanks,
Sam

[thatswagenwagen]

Okay so I did the LED tests... and the pressure relief solenoid seems to be ALWAYS ON...not good. It is currently spare output #1 selected to operate as a selective clutch, is there a mod that I was supposed to do to the board to use it as a Sel. Clutch??

I tried setting it to "User Spare port", gave it some constraints: "dont activate until speed over 20 and gear = 3rd.." and it activates at the proper time, but does not deactivate... Even after I slow down to 10mph and drop to 2nd... isnt the CPU supposed to have a hysteresis for speed and deactivate the solenoid after that parameter is met? Or am I missing something?

Thanks
Sam

All I need is for the GPIO to operate a selective clutch and an extra solenoid. its that easy, or not.

[Bernard Fife]

Sam,

I will have a look. I assume you are still using the msq above. If your settings have changed could you post your msq file?

Lance.

[Bernard Fife]

ttw,

There is no hardware mod required for SP1 in selective clutch mode. You just need to built the VB1 circuit (there is a wire jumper required from PT7 to VB1 on the 25x2 header, but this is part of the standard build).

Could you try 5.094 test code (below). It appears to work fine with the selective clutch on SP1 on my bench. Any fixes would have gone into the 5.xxx series anyhow, as we are readying this for release in the fairly near future (and the 4.1xx series will then be obsolete).

Monitor_5094t2.abs.s19

(78.38 KiB) Downloaded 742 times

GPIO_MShift_5094.ini

(260.99 KiB) Downloaded 757 times

If you could post a datalog made while using this code, that would let us see what is going on. In particular, it would be good to see if the "Sp1%" value is responding appropriately. If it is, I would then suspect a hardware problem (likely a short somewhere).

Also, remember that 100% *might* be OFF for your solenoid, depending on the way you built the circuit and the device you are controlling. If it is the case that 100% is off for you, then you need to set the 'PWM% when inactive' to 100% under the PWM setup menu. Then you can set the PWM table to lower values (for example, all 0% if you want an on/off switch that responds only to the shift state and not at all to load, etc.).

Lance.

[thatswagenwagen]

Hey Lance,

I tried changing the PWM1% (selective clutch) to 0% across the board like you said, all that did was make nothing work.. it seems as if it uses that table to decide what spike to go to when shifting gears.

So today I went ahead and tried a few things. I attached the solenoid ground wires to led strips and found out what is happening and why it is slipping.. The transistors are staying grounded even after they are told to 'unground'. Heres what happens:

- I start car, switch to manual mode..
- Then I change gears from 1st to 2nd, and the shifting solenoid comes on when told, but does not go off... (the datalog says it should be off but it isnt.)
- Same with the 3rd/4th shift solenoids, they ground when told, but the LEDs tell me that the transistor never ungrounds.

Today on the highway I cut the wire to the selective clutch and surprise, my 4th gear dug in and stopped slipping. Pushed it lightly to 115mph and called it good. So yes, the grounds arnt working right!! Heres my datalog: I am suspecting either mismatched settings or a bad solder job...

Thanks,
Thomas Henao

[thatswagenwagen]

The datalog: It says everythings working properly, but it is not...

[thatswagenwagen]

Oh and one more thing,

What all can get damaged when a PWM circuit gets run without a flyback... because I know for a fact that I ran those solenoids without a flyback for about a week until I realized that the outputs were getting pulsed. Could it be damaged hardware from those events?

Edit: at this stage I am suspecting 2 (SP1 and SP2) faulty TIP120s due to excess voltage on unprotected flyback.. I will go buy some new ones and try again.

Sam

[Bernard Fife]

Could it be damaged hardware from those events?

It is certainly possible. The TIP120s are the most likely victim, as you suspect.

Lance.