Shift Target sets to -99 sometimes

[mill3833]

Lance,

Sometimes MSShift will set Shift Target (tGear) to -99. So far this seems to happen when I move shifter manually into 1st or 2nd, and then start a roll-out. The attached MSL is from a drive on the street. When it happens, it is stuck in 1st gear for that power-cycle. Cycling ignition (engine off/on) fixes the problem. Tonight, while on jack stands, it did it also, but I wasn't logging. This time, I left engine running and pulled the MSShift fuse to reset it. MSShift came back up and TS resumed monitoring. That cleared it, and it behaved itself for another 15 mins of running on the stands, trying to get it to repeat, but it didn't.

This sounds similar to what pr0teus wrote about on Wed Apr 02, 2014 7:15 am .

I verified my Manual shift lever corresponds to unique switch combinations. It is a 1994 Camaro, 4L60E. And today on the stands, it worked flawlessly, after fuse reset, shifting manually, manual gear selector just limited the shift to the selected position. Apparently no 2nd gear start, like some OEM tunes.

Am running 4.1.3.8 code. Attached is MSL and MSQ.

So what does this -99 mean? Any troubleshooting ideas?

Thanks,
Dave

[Bernard Fife]

Dave,

I haven't looked at your datalog yet, but are you sure it is the target gear (tGear in the datalog) that is set to -99?

I ask because the manual gear (mGear - the lever position) can be set to -99 (indicating that the code could not find a match between the inputs and the user's lever patterns), but there is no place in the code that I can see where the current gear (cGear) can get set to -99 or that the target gear (tGear) can be set to -99.

Lance.

[mill3833]

Looking closer at the data, yes, mGear does got to -99. 2.5 sec later, tGear goes to -99, which is what I had up on TC real-time. Once mGear goes -99, does something in the code latch, such that a power-cylce is required to clear the fault?

So based on this, I'm suspect the A-B-C valve body membrane switches, and/or grounding. I have very good grounds right to the drivers-side cylinder head, but maybe there's a slight difference between that point and the trans valvebody.

The fact that this is intermittent (works most of the time) means I have the mapping correct. I wonder if the wetting current for these discrete inputs is marginal? ie, increasing wetting current may make switch contact more reliable? I might have to power-up the stock PCM and measure its wetting current for these inputs.

Thoughts? Comments? I'm thinking opto-coupling these three discretes.

Dave

[Bernard Fife]

Dave,

After thinking about this and looking through the code some more, there may be a 'back-door' through which the target gear is getting set to -99. I will attach some code that might help:

Monitor_4141.abs.s19

Test code only, this is not release code.

(72.79 KiB) Downloaded 693 times

GPIO_MShift_4141.ini

Test code only, this is not release code.

(218.44 KiB) Downloaded 691 times

The -99 error should clear once a recognizable signal patterns is established. I think you might also need to experiment with the lever error behavior to match your setup. There could be intermittent errors that are causing issues. See the info on Lever Error Behavior and Lever Error Delay here: http://www.msgpio.com/manuals/mshift/V41tune.html#ge.

You might also need to adjust the Digital Voltage Threshold: http://www.msgpio.com/manuals/mshift/V41tune.html#il

Lance.

[mill3833]

Lance,

Thanks for pointing me to the links.

Looking at my data, I was pleased to find raw ADin1,2,3 voltages. When the -99 happened, there were some spikes on one of the input that reached above 1v (my V threshold). So am suspecting that. I'll raise that to 2.5 V and will pay attention to mGear on TS.

This backdoor setting of -99, would this explain why it latched to -99 and required power cycle to clear? Just trying to understand if its worth upgrading to 4141. To do so, I have to doctor up the ini file with some of my custom stuff.

Thanks,
Dave

[Bernard Fife]

would this explain why it latched to -99 and required power cycle to clear?

Dave,

Yes, it is certainly possible, and this code *should* fix it if the problem was what I thought it was.

Lance.

[mill3833]

I will load it up and try it.

Now that I know I have a sensitivity to the 1V threshold, I can bring that down to 0.1 and prove that it latches-up (with 4.138 code) then switch it to 4.141 and see if it fixes it.

Thanks,

Dave

[mill3833]

Well,

Was able to get the error code 33 to set, and the -99 to happen with the 4138 code and with 0.1V threshold and 2.5V thresholds. Slap shifting does it (moving shifter too quick), and it latches up.

So next trying to load up the 4141 code. It loads up and verifies ok. But am having troubles with TS. TS gauges are all red X-ed out. Also get some kind of "X and Y" error. Actually it does connect, and I can burn and change values, but all the gauges are X-ed out, ie no data is streaming from MSShift. Guess I don't know enough about TS to understand the issue. Something in the ini file?

To test my programming process, I loaded 4138 back on it, and it works. Loaded 4141 up and is still broke.

Any ideas? Screen shot attached.

Dave

[Bernard Fife]

Dave,

Something is very wrong, and I wouldn't trust your results if the comms aren't working properly (it would be impossible to say which errors were due to the bad comms, and which errors were genuine).

I have tried the most recent 4.141 code and INI and the comms work fine here.

If this was mine, I would re-download and reinstall both the code and INI from this thread: viewtopic.php?f=4&t=9&p=4317#p4317

Lance.

[mill3833]

Lance,

My comments about operation was with the 4138 code. I have not tried running the car with the 4141 yet, because of the TS streaming issue.

Here is a better explanation of what I saw with the 4138 code. This was with car on jack stands. As long as I moved the shifter relatively slowly, things work fine. As soon as I slapped it from D3 to D1, then sometimes I'd get error 33 and mGear showed -99. From D1, if I released the brake and let the propshaft spin, then tGear would show -99. tGear=-99 changes to 1 when propshaft stops, but mGear stays latched at -99 until power-cycle.

I'll try 4141d from the other thread tomorrow.

Dave