Manual Gear Shift Lever Reads 0 when set to D3..

[pr0teus]

I have a Megashift set up in standalone configuration in a 1994 Chevrolet K2500 Silverado. I have two issues at the moment, though they may be possibly related.

First off, when I load up the gauge for the Manual Gear in TunerStudioMS and then shift through each gear, the gauge seems to read correctly for most gears (1 for D1, 2 for D2, 4 for D4), but Reverse and D3 are incorrect. I get 3 for Reverse and -1 for D3. Any ideas as to what may be causing this? Something with the pressure switch manifold perhaps?

Second, automatic shifting works great, as intended, but only when the manual gear shift lever is put into D4. When I select D1, D2 or D3, it does not shift at all.

If any additional info is needed, just let me know. Thanks!

Andy

[Bernard Fife]

Andy,

Yes, these are most likely related. There could be a number of causes. The best place for us to start the diagnosis is with an datalog showing the issue and your MSQ setting file. If you could post those here as attachments we can have a look.

Lance.

[pr0teus]

Ok. Here are the MSQ and MSL files. First off, I am cycling through all the manual gear shift lever positions. Then, I put it into drive and step on the gas. It doesn't shift. I then put it into 1st and once up to speed I try shifting into 2nd and it doesn't register. Finally, I put it into 4th (Overdrive) and then the shifting works just fine as I take the truck back home and into the driveway.

Also, I am using beta code v5.014. I get the exact same behavior using release code v4.137. I haven't tried v4.138, but I assume there would be no change in behavior for me. Please let me know if there is anything else you need, or if you have any suggestions for me to try.

[Bernard Fife]

I will have a look shortly.

[Bernard Fife]

Proteus,

There was an issue that showed up in your datalog in which the target gear was being set to 0 while the shift lever was in a forward gear, and this should never happen. This could certainly be causing the problem you are seeing. I believe we have fixed this in the attached 4.138 test code (the INI is unchanged).

Monitor_4138t.abs.s19

(72.62 KiB) Downloaded 578 times

GPIO_MShift_4138.ini

(218.03 KiB) Downloaded 553 times

Let us know if this helps or not.

Lance.

[pr0teus]

Thanks, I'm just putting a new intake manifold on the truck and then I hope to be able to try this out later tonight. I'll let you know how it goes after a test drive later.

[pr0teus]

Sorry for the late reply.. Anyhow, I tried the firmware you uploaded and it didn't fix the problem. You can see near the end of the attached log file that the manual gear is still being read wrong when in drive (says '0') or in reverse (says '3'). This new log file is made with the new firmware too, which also gets me the same behavior. Any ideas?

[Bernard Fife]

proteus,

You mean when the inputs are in1 = 1, in2 = 0, in3 = 1 (around 3802.5 seconds in your log)? Your msq has this as Park under 'Shift Input Patterns', so I would expect the manual gear lever position to read 0 as the datalog shows (the target gear reads 1 and the current gear reads 0).

And do you mean at the end of the log when the mGear (the manual gear lever position value) is 3 when the inputs are in1 = 1, in2 = 1, in3 = 0 (around 3825.2 seconds in your log)? That's the pattern you have for third gear.

If this was mine, I would shift the lever into each gear, note the inputs states for in1, in2 and in3, and then enter these for the Shift Inputs values for each position. Note that the positions must be unique (except for Park and Neutral).

Or are you saying that the inputs (1, 2, & 3) don't reflect the actual voltage states on the inputs? In that case, what voltages are you measuring in each manual gear position?

Or are you saying that the input 1 signal is intermittent (it does jump around a fair bit) near the end of the log? This might be a loose connection or a soldering problem in the input circuits.

Lance.