Help with 4L80E

[gui67]

You can try to test all the functions separately. I don't have the trans-stim, and did that to test the board.
I used once the RPM generator from the jimstim for the MS and an other time a signal generator.
For the other inputs, I ground them to simulate the different positions of the lever.
And I use the Injector and ignition leds from the Jimstim to check the outputs.
What you could do is to put temporary switches to simulate the manual upshift and downshift buttons. You go in manual mode, desactive the RPM check and pass the gears manually.

If it is OK, you do the same in the car with the wheels of the ground and check if oss is increasing when you increase the gears.

Maybe there is a problem with the msq too, I am not using the same code as you I think. so from one code to an other, some parameters might need to change. Did you have problems while opening the tune?

[flak monkey]

Thanks, I tried creating a new MSQ too, when I loaded new code I just used the base map and changed the output solenoid settings and PC solenoid settings etc for the 4L80, made no difference.

But I've had some measure of success tonight...

I loaded an old version of the firmware - 4.146 infact.... created a new MSQ and it now seems to be working and shifting gears. See datalog and attached MSQ.

My ISS still doesn't work properly though. So perhaps I have a physical problem with that? If you look at the signal in the log it jumps between values - which is odd.

And my TCC is stuck locked - I'm not sure if this is a fault with the MSQ or the transmission yet.

[gui67]

It seems much better now.

I see in the msq that the ISS is disabled.
You also have a problem with the number of VSS teeth

for the TCC, I had once this problem, Everytime the transmission went in second gear, the TCC would engage (it cannot be engaged in first) and the engine would stall.
It was the transistor that was burnt and grounded the TCC output permanently. You can check if the output is always grounded also with the car on neutral or in reverse... then check the transistor... or the wiring?

[flak monkey]

I am using a DRAC for the VSS - so the number of teeth and axle ratio are adjusted to get the speed reading right in TS.

http://www.msgpio.com/manuals/mshift/drac.html

Well spotted - wonder why I was getting some sort of readings in the first place. I'll turn it on and see if it works properly after that.

Mine is engaging in 1st gear, as soon as you put it in drive. Seems it's possible for it to be applied if the fluid flow in the converter isn't high enough - Sonnax do a valve that apparently helps with the issue. I've ordered one to try it out.

I didn't think to check to see if my speedo was working now - will check that another time.

It did seem to take a long time to shift gears - see in the log from 658 sec to 666 sec before it shifts? Why would that be?

[flak monkey]

I noticed when datalogging that the 'upshift req' is permanently on in the log...

Any ideas why?

[Bernard Fife]

It did seem to take a long time to shift gears - see in the log from 658 sec to 666 sec before it shifts? Why would that be?

Flak Monkey,

In this case, the shift didn't happen sooner because the target gear didn't change until 666.792 seconds. Then the shift happens at 667.015 seconds (so shortly after). The target gear not changing could be because of the way your shift table is set up, because of hysteresis, because of rpm limiting, or a number of other factors. Your datalog looks strange in that the rpm doesn't to 2nd, which is odd.

[flak monkey]

Thanks Lance.

I might experiment with changing my load to TPS as in the past I have preferred how the shifts happen like this.

I know that my TCC is stuck locked at low speed at the moment, this might be why the RPM's look wierd at the shift from 1st to second as I expect it's unlocking as it shifts. I know that it's shifting, I can feel and hear it shift.

I have the common problem with a lack of fluid flow causing the lock up clutch to not disengage fully in first gear, I am pulling the pan this weekend t change the pump valve to increase flow and hope this fixes the problem. Very common apparently...

[flak monkey]

Right... some progress.

I noticed that my speed was stuck at 5mph with the sensor disconnected. Couldn't find any faults so I removed the DRAC and connected directly back to the VSS and now have a better speed signal. Perhaps there was an issue with the way my DRAC was installed.

Now have better speed signal and I can run the VSS as I should with the correct number of teeth etc.

But I still have a couple of problems

1. The transmission starts in second gear in every lever position other than 1, when it will shift down to 1st. I can't see anything wrong in the datalog that could cause this? You can see that there is no RPM or speed change when the transmission shifts from 1st to second in the datalog.

2. Why does it take so long for the transmission to shift when the table says it should be in a higher gear? I've tried changing the shift factors, but it hasn't made any difference.

Could someone please help by taking a look at the datalogs and MSQ attached?

Thanks
Sera

[Bernard Fife]

Sera,

In your datalog, as in the previous one, the shifts (cGear) immediately follow the change in the target gear (tGear). So you may be asking why the target gear isn't changing. That may be because of a few things, but one possibility is that you are not using the shift table you think you are. There are two shift target gear tables, and which one is in use is determined by the state of the input on PE1/GPI1/Amp5.

That could also cause the 2nd gear starts, as could having the 'follow mode set to an inappropriate value: http://www.msgpio.com/manuals/mshift/V5tune.html#gs

[flak monkey]

Hi Lance,

Thank you

It does indeed look like its defaulting to use shift table 2, rather than table 1. The 2wd/4wd is floating at the moment, I had intended to use it to provide a 'Sport' mode via a toggle switch. Looks like it works opposite to what I thought. Presumably if I ground this wire it will switch to using table 1?

The shift points in this table seem to match those in my log... better than table 1

table 2.JPG (95.93 KiB) Viewed 12265 times

However they still don't match perfectly with table 2, according to the log I have shifts at:
1-2 39mph
2-3 49mph
3-4 75mph

Only the 2-3 and 3-4 ones make sense. The 1-2 shift should have been at 16mph?

shifts.JPG (83.67 KiB) Viewed 12265 times

But if you shift the lever into 1st it does shift down and stay in gear.