NefMoto

Technical => Tuning => Topic started by: maciek on November 23, 2019, 06:10:45 PM



Title: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on November 23, 2019, 06:10:45 PM
Hi,

i converted my Lotus Elise with an Audi 1.8T engine and have issues with reading the speed signal as i dont have the abs/esp unit installed in my car.
Tried pin 54 (blue/white) but no success. Do I have to patch the ECU to configure it to not use CAN for the speed signal? Any help appreciated.

Cheers,

Maciek   


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on November 23, 2019, 06:26:00 PM
Do I have to set CWGGVFZG to 0x00?


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: _nameless on November 23, 2019, 08:01:22 PM
Do I have to set CWGGVFZG to 0x00?
0 is vss
1 is can or vss
2 is can only


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on November 23, 2019, 09:04:33 PM
Hmm , then I'm doing it wrong. It is set to 0 already. Address is 14329 right?

Cheers,

Maciek


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: dal on November 24, 2019, 03:26:09 PM
From what I know (not sure), the VS always pass by the cluster. Either from ABS -> Can -> Cluster -> ECU or VSS -> Cluster -> ECU.


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on November 25, 2019, 11:14:41 AM
Thank you. Will measure the signal with an oscilloscope in an original car. Don't have the org cluster in the Lotus.
Currently the G22 signal is wired directly to the ECU, which is wrong as you said. Have to convert it to a GALA probably.


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: prj on November 25, 2019, 11:42:08 AM
The real question is - do you really need the speed signal?
There aren't that many things really depending on it. Especially with a manual gearbox.


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on November 25, 2019, 11:49:55 AM
Yes, think so. The car is very light and jerky when going slowly in 2nd gear for instance. Have to press the clutch then to not nod my head like crazy  ;D 


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: prj on November 25, 2019, 01:05:48 PM
Having speed signal will most likely not magically fix it.


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on November 25, 2019, 01:12:02 PM
Hm, so any ideas whats wrong?  It's all stock like in a S3 engine but without the speed signal. A stock Audi runs much smoother. Throttle resonse in the Lotus is very aggressive


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: prj on November 25, 2019, 02:21:03 PM
What's wrong? Well it's not in an Audi for starters, the chassis is probably lighter, the flywheel is probably not stock.
ARMD & friends is probably having a field day, and there is a lot of other stuff to take care of too.

I mean, someone needs to look at it who knows what they are doing. And I mean physically look at it.

You can try to get the speed signal to work, but as I said, most likely it will not be a magic fix to your drivability issues.


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on November 25, 2019, 02:31:23 PM
Thanks for your help !  I think ARMD needs gangi to work and without vehicle speed it's  disabled. But anyway I'll simply have to try it and report if it worked or not. Other than that I recommend 1.8T in a Lotus and wish more people would go for it and then discuss it here  ;-)

Cheers,

Maciek


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: jochen_145 on December 01, 2019, 09:31:39 AM
From what I know (not sure), the VS always pass by the cluster. Either from ABS -> Can -> Cluster -> ECU or VSS -> Cluster -> ECU.

no, not exactly:
source of vehicle speed ist ABS/ESP -> CAN.
Depending of generation of car, ECU and Cluster will parallel read VS from CAN or (older cluster without CAN) ECU will read VS form CAN and send it via puls-signal to cluster.

AFAIK there is no VSS-input on ME7


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: dal on December 01, 2019, 05:43:27 PM
no, not exactly:
source of vehicle speed ist ABS/ESP -> CAN.
Depending of generation of car, ECU and Cluster will parallel read VS from CAN or (older cluster without CAN) ECU will read VS form CAN and send it via puls-signal to cluster.

AFAIK there is no VSS-input on ME7

I see... so help me with my case. My A3 8L dont have an CAN gateway on the cluster. If I unplug the cluster fuse, the ECU dont have VS anymore.
So based on what you told, my ECU was supposed to have VS signal even with the cluster disconected, but this dont happen.


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: macxxx on December 01, 2019, 11:36:30 PM
As i know on audi platforms like a3 8L , a4 b5 , a6 c5 - vehicle speed goes from a speed sensor from gearbox to cluster - then it is send by cluster ( analogue or can ) to the ecu and other control units ( radio , wiper control , centr locks )


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: vwmaniac on December 02, 2019, 07:31:24 AM
most audi me7.5 ecus use can for speed signal. abs can> cluster (can gateway)> ecu   When an analog signal speed sensor> cluster> analog to ecu. the cluster can be cut out of these equations and Can can be run directly from abs module or signal directly from sensor to ecu. Also PRJ i have noticed that when speed signal at least analog is disconnected there are some adverse effects, seems to be part of the torque monitoring is effected. definitely not as smooth as with the sensor or speed feedback. here is a video to show the difference between a can ecu and an analog ecu https://youtu.be/8x-pMrDO4CI
 


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on December 02, 2019, 08:13:08 AM
Thanks for your input. Hope the "analog signal is possible" party is right. I'll have access to the car in two weeks. Oscilloscope and signal generator are available. I'll let you know.

Cheers,

Maciek


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: vwmaniac on December 03, 2019, 07:07:56 AM
technically dont need a signal generator, if you pulse ground to pin 54 and follow speed signal on a scan tool you will see the speed come up just like in my video.


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: maciek on December 25, 2019, 01:35:26 PM
It works, thank you all :-)
My ecu detects the speed signal when I pulse ground to pin 54, as vwmaniac said.
All you need is two resistors to get a signal from the hall sensor at the gearbox and then with that signal pulse ground with a mosfet to pin 54.

Cheers,

Maciek


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: Scheitan on July 08, 2022, 04:05:14 AM
Does someone have more info how the wiring looks with a mosfet and ans hallsensor and ground?

Have same issue


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: nupustas on July 09, 2022, 12:24:42 PM
most audi me7.5 ecus use can for speed signal. abs can> cluster (can gateway)> ecu   When an analog signal speed sensor> cluster> analog to ecu. the cluster can be cut out of these equations and Can can be run directly from abs module or signal directly from sensor to ecu. Also PRJ i have noticed that when speed signal at least analog is disconnected there are some adverse effects, seems to be part of the torque monitoring is effected. [/b]definitely not as smooth as with the sensor or speed feedback. here is a video to show the difference between a can ecu and an analog ecu https://youtu.be/8x-pMrDO4CI
  

Hi,
im stucked with torque intervention and cant find problem. My car 1,8t+me7.5, but in old body(no abs, no speed sensor, no instrument cluster-just alone ECU). Rpm NMAX, NMAXOG 7200, NMAXF 7500, but i cant reach it due to throttle cut. Maybe this can be affected by unpluged speed sensor?
P.S. interpoltaing/tuning/leaving stock kfmirl/kfmiop doesnt help


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: BlackT on July 09, 2022, 01:24:09 PM
NMAXGA


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: nupustas on July 09, 2022, 02:08:26 PM
NMAXGA

THANKS  :) I spent a lot of time and fuel while logging, NMAXGA must be solution (tomorow ill try to log)

Should i change all fields in this map?


Title: Re: Vehicle speed signal Audi ME7.5 without CAN possible?
Post by: nupustas on July 09, 2022, 10:51:52 PM
Problem solved - it was not torque intervention, but just RPM limiter. Thanks BlackT for right direction.
Also while digging info about NMAXGA, desided adjust 2 additional maps: NMAXDV and NMADVG, especially when i have fault code in ecu "wrong speed sensor signal". After setting these 3 maps, i can finally rev up to new rpm limit