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MG MGF Technical - RPM and ABS signals

Hi all,

As I am designing a Traction Control System for my yet to buy MGF, I am searching for information on the RPM and ABS wheelspeed signals. I have already bought a digital manual, but I find the information in this manual insufficient.
I hope someone can help me answering the following questions:

- How many pulses are generated on each revolution of a wheel by the wheelspeed sensors (in other words: how many teeth are there on the wheelspeed cogwheel)?

- How many pulses are generated per engine revolution.


Also, I found the electrical drawings very brief. Can anyone help me find a more detailed circuit drawing of mainly the Engine Control Unit and its sensors and actuators.

Thank you and best regards,

Alex
A.P. van Wijngaarden

Engine speed is number of bangs per rev => 2 for each rev

Can't help with teeth per rev for tyres

Why do you need engine rpm?
Surely you want diffrential wheel speed and steering rack position?
Will Munns

The traction control system will need the RPM to prevent the engine from stalling.

The steering rack position is not really necessary. The steering angle can be calculated by the difference in wheel speed of the front wheels. I think the steering rack position is only needed in front wheel driven cars. I hope I can do without.
A.P. van Wijngaarden

Ahh, OK.

Do you intend to cut power by progressivly cutting sparks? if so then just use the signal you have there (1 per RPM for twin spark or 2 per RPM for distributor)
Will Munns

I think that Brown and Gammons used to sell a Racelogic system

http://www.ukmgparts.com/cgi-bin/gen5?runprog=bg&cat=MGF&cov=Y&mode=detail&o=10441854159027&code=BGF6040&filen=mgf12&head2=MGF
David Clelland

There are two possibilities to cut engine power, either by spark cutting or fuel injection cutting. I do not know which to use yet, because I do not know how the engine control unit will respond to either one. Also, when using the ignition cut, the catalyst has to be removed, because of the unburned fuel entering it.

The Racelogic system is indeed quite nice and I have already considered it. The main problem is that I do not grow my money in the backyard and I think it is quite nice to design such a system myself.
A.P. van Wijngaarden

There may be more information on Dieter's website, from when he installed the Becker sat nav to his F... err, no, just checked: the sat nav uses the speedo speed signal :o(

Alex, the MGF uses a Bosch ABS system, so perhaps you may be able to find out more by searching the net for characteristics of the Bosch wheel sensors?
Rob Bell

> either by spark cutting or fuel injection cutting.

As I understand it most systems cut spark because the injectors don't fire into an open port, they batch fire so the outcome of cutting the fuel may be a half lean burn causing detonation.

The ECU will throw a warn on later systems as the lamda shoots off the scale, on later cars this will light a lamp and throw the engine to limp home mode.
I don't think the ECU uses the Lamda for anything when running open loop (anything except steady state) as far as fueling goes, so on early cars this should be OK.
Will Munns

This thread was discussed on 07/03/2005

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