VW MK3 01M on MegaShift

[thatswagenwagen]

Hello,

I have recently come to a halt trying to get my 01M 4Speed on the road. While on jackstands it will shift through 2-3 and 3-4 (I feel the shift and the speed rises), but does not engage 1st gear for some reason. Current gear shows 1st, but it is actually in 2nd... any ideas on where to look for trouble? I have connected 3 LEDs to the Shift outputs and gotten perfect results for shift solenoids/selective clutch's. Attached is a technical document for the 01M and my msq.

Thanks ,
Sam

[Bernard Fife]

Sam,

It could be a number of things.

It could be the external wiring (between the GPIO board and the solenoid) or it could be in the internal wring (one of the shift solenoid outputs not built correctly, built with defective or damaged components, or having some sort of short or break).

It could even be due to a misreading or incomplete understanding of the requirements of the transmission.

If this was mine I would start by doing what you did with the LEDs - that tells us that the circuits are being switched as commanded by the software and its settings. But it doesn't necessarily imply that the circuits are correctly switching the much higher current of a solenoid. So I would probably try with some small 12V bulbs that draw roughly the same current as the transmission's solenoids (probably about 1 Amp). But first I would make sure that the solenoids are getting the full 12V, and that the resistance from each solenoid to its pin GPIO ampseal connector is minimal (less than 1 Ohm, ideally), as a poor connection there is a more likely problem.

If you are using PWM on the solenoids, it is possible that this isn't high enough to switch the solenoid, so that may be something to check too.

I can't use your MSQ, I need one just for MShift. And we really need a datalog to go along with the MSQ before we can say how things are working compared to how they ought to work.

Lance.

[thatswagenwagen]

Hey Lance,

Thanks for the reply. It was actually a silly thing.. when unloaded, first gear (a freewheeling gear) does not cause the car to shudder because it is freewheeling the whole time. As soon as I got it on the ground this was quite evident.

But I have moved on to much bigger things with this controller.. And gotten it to shift (almost smoothly) through all 4 gears.

However, being a turbo car the KPA Will not cut it. And I have been having pretty erratic shifts even after hours of tuning it. As soon as I am on boost it does one thing, and then jumps to another gear... Cant explain it I will have to get a datalog together.. But the KPA doesnt matter anymore, my real question is HOW DO I GET IT TO SHIFT BY TPS (instead of Vaccum/boost MAP)!?!.

For hours I adjusted settings in Megatune to try and get it to respond to the TPS instead of MAP. I changed the project settings to GEARTABLEMAP-DISABLED to no avail. It even says MS2tps on the LOAD bins.. But Megashift still seems to be shifting like it is on the old MAP table. The TPS vs SPEED blue dot thingy (that shows which gear should be selected) will be well into 3rd gear and it is still driving in second gear! No upshift requests.. Just driving as if the MAP is controlling it.

I will continue scouring the forums for others with the same issue!

Thanks for the help! (I know you need a msq and ini, so I'll have to post them separately via the tuning computer)

Awesome transmission controller by the way.. Never thought I would get this far with it!

Sam

[thatswagenwagen]

Ahahaha Never mind! It is a setting under CAN Configuration Called: "CANBUS Load Variable" For anyone as dumb as me

Should be shifting great now I'll report when Its not 2:00am, Sorry for wasting time! lol

Sam

[Addicted]

Great news Sam, let us know how you get on

[thatswagenwagen]

Ok been tuning it for a few weeks and finially got it to shift smoothly into 4th gear and not neutral drop lol.

However, the VSS will randomly report 8mph when on the freeway and as you might be able to tell that causes a rapid 2nd gear switch, drivline jolt, and a 6,000 rpm motor.... Now I wont go above 55mph just to protect my new motor..

If it blows up I have a VR6 in my backyard so its ok (;

So what could cause a random 0mph reading? I took off VSS smoothing so the speed returns to actual speed quicker.. but that still is not a fix. Could it be a dirty sensor? Bad sensor return wires? theres about 1ft of signal wire that is not twisted with shield wire near the TCM.

Thanks guys!
Sam

Oh a big thing with the VW/AUDI transmissions is setting the selective clutch PWM application percentages, Under Tuning you will find the PWM% curve that varies with load. Setting it right made shifting 100% better for me.

[slyrye]

Ok been tuning it for a few weeks and finially got it to shift smoothly into 4th gear and not neutral drop lol.

However, the VSS will randomly report 8mph when on the freeway and as you might be able to tell that causes a rapid 2nd gear switch, drivline jolt, and a 6,000 rpm motor.... Now I wont go above 55mph just to protect my new motor..

If it blows up I have a VR6 in my backyard so its ok (;

So what could cause a random 0mph reading? I took off VSS smoothing so the speed returns to actual speed quicker.. but that still is not a fix. Could it be a dirty sensor? Bad sensor return wires? theres about 1ft of signal wire that is not twisted with shield wire near the TCM.

Thanks guys!
Sam

Oh a big thing with the VW/AUDI transmissions is setting the selective clutch PWM application percentages, Under Tuning you will find the PWM% curve that varies with load. Setting it right made shifting 100% better for me.

could be your VR sensor conditioner getting messed up with continuous bombardment of electrical noise... just a thought

[Bernard Fife]

Now I wont go above 55mph just to protect my new motor..

tww,

Do you have RPM checking turned on? (See: http://www.msgpio.com/manuals/mshift/V41tune.html#gr) This is designed to prevent over-revs (and under-revs) at any time (i.e. it blocks shifts that will over/under rev the engine, and it will also force an up/down shift if the engine exceeds the set limits at any time between shifts). So if this is set properly (or even conservatively if you want to be absolutely sure) the engine should be safe.

could be your VR sensor conditioner getting messed up with continuous bombardment of electrical noise

Yes, it could certainly be that, as this is most frequently the issue with VSS signals. It might also be a dodgy connection somewhere in the VSS path. There are some other tips for setting parameters, etc. here: http://www.msgpio.com/manuals/mshift/vss.html

In any case, new code is coming that could help with this VSS drop-out issue (I am working on it now).

Lance.

[thatswagenwagen]

To all,

It has been a month with the Megashift functioning pretty well. I use manual mode now for high speeds and have been experimenting with different resistors in the 300K (R59?) slot. Low resistors (100K-200K) seem to make it worse, and I have not tried resistors higher that that.

I will definitely check for noise.. A transmission with spinning metal wheels must be pretty noisy.
Time to get the Oscope out..

I have RPM Checking ON, I think it is worth noting (in the manual) in bold print that anyone doing a crazy project with non-GM sensors should always use manual mode and take a datalog to see is VSS is going to dropout.

Even with RPM checking on, the controller thinks that the car is going 10mph so it will disregard VSS the rate of change and throw you into 1st/2nd briefly.

Also what happens if you have an emergency and have to momentarily lock up brakes going 70mph? the VSS will read 0 and the current code will drop gears...

Thanks for the excellent support gents!
Sam

[thatswagenwagen]

"Here's my datalog, It appears that the VSS gets errors when accelerating and is perfect and smooth when decelerating.. Anyone know what may cause this??"

Nevermind, it was a bad tire calc (wrong diameter boo) and a noisy signal (duhh). VSS Still drops out but now only drops to 30mph, I will continue rising the masking as per the manual.


One BIG Question though!! During shifts, my PC does not change how it is supposed to... I do not see a 40% drop like I tell it to when going from 1-2. as you may guess, This causes really rough shifts that I cannot control... Attached is my snipped datalog. Is there a setting that I have not selected?? One thing to note is that the PC does change to 40% on downshifts, just not on upshifts!!

I am on code 4.145 with a CAN enabled MSII V3 In charge.

And I dont have a "CAN VSS" selection for my MPG settings!! It only has "userSpeed" and "GPS Speed", so no mileage calcs for me

Thanks!!
Sam