Drive by wire

Norbit · Post by **Norbit** » Thu Feb 22, 2007 11:05 am

May i know microsquirt can use as piggyback or stand-alone on car with drive-by-wire throttle body ?

I am new to this forum and i also not sure this topic posted before or not . Pls help to show me the thread if posted before . Thanks

Matt Cramer · Post by **Matt Cramer** » Thu Feb 22, 2007 11:18 am

Microsquirt cannot control a drive-by-wire throttle body, but it can take over control of the injectors or ignition control on some cars that have one. You will need to leave the original ECU in place to operate the throttle body or convert it to a cable operated throttle.

Norbit · Post by **Norbit** » Thu Feb 22, 2007 11:46 am

Thanks matt

I have another question if MS run as piggy back in auto transmission car will cause jerk during cruising at certain rpm .

Our auto transmission car here running with TCU ( From mitsubishi ) + ECU ( siemen EMS 700 ) not all in one . I got 2 mates have tried on unichip . Both of them faced same symptom , car jerk intermittent at certain rpm . Actually i plan to supercharge my NA auto transmission car and i need piggy back to control additional injector , but i scare to get same symptom as mentioned above .

Matt Cramer · Post by **Matt Cramer** » Thu Feb 22, 2007 12:40 pm

Microsquirt won't be able to control the transmission, at least not until the GPIO board comes out. If you get the engine tuned to operate smoothly and you do not have any trouble with a computer controlled transmission going into limp-home mode, you shouldn't have this problem.

But a bad tune can certainly cause this sort of thing. An ECU can't perform better than its tuning.

Norbit · Post by **Norbit** » Thu Feb 22, 2007 4:58 pm

Any wiring diagram to show MS as piggy back ?

My car running with components as below :-

1) siemens MAP sensor ( 3 wires type )
2) distributorless ignition system ( Built in ignition module )
3) Single pin water tem sensor
4) Crank sensor ( How to determine type of this sensor )
5) Drive-by-wire throttle ( 6 wires type )
6) Siemens O2 sensor ( 4 wires type )
7) Siemens fuel injector

Norbit · Post by **Norbit** » Tue Mar 06, 2007 5:09 am

matt ,

sorry need to bother you again . Does MS can communicate well with ecu that using infineon ( sk-c167cr-lm H+ ) micro controller ?

Matt Cramer · Post by **Matt Cramer** » Tue Mar 06, 2007 10:32 am

Norbit wrote:matt ,

sorry need to bother you again . Does MS can communicate well with ecu that using infineon ( sk-c167cr-lm H+ ) micro controller ?

It won't communicate with the Infineon microcontroller at all. "Piggyback" Megasquirt installations actually take control of the injectors and/or ignition timing away from the ECU altogether and place them under Megasquirt control - the Megasquirt does not take signals to the ECU and modify them like a true piggyback.

It's worth noting that the main drawing of how to wire up a V2.2 board would, in fact, be a "piggyback" installation in that if you used that diagram on a car with computer controlled timing it would leave the ECU in control of the timing. The only difference is that you would remove the TPS VREF line and several of the sensors would be shared with the stock ECU.

Norbit · Post by **Norbit** » Wed Mar 07, 2007 12:51 am

Matt Cramer wrote:
Norbit wrote:matt ,

sorry need to bother you again . Does MS can communicate well with ecu that using infineon ( sk-c167cr-lm H+ ) micro controller ?
It won't communicate with the Infineon microcontroller at all. "Piggyback" Megasquirt installations actually take control of the injectors and/or ignition timing away from the ECU altogether and place them under Megasquirt control - the Megasquirt does not take signals to the ECU and modify them like a true piggyback.

It's worth noting that the main drawing of how to wire up a V2.2 board would, in fact, be a "piggyback" installation in that if you used that diagram on a car with computer controlled timing it would leave the ECU in control of the timing. The only difference is that you would remove the TPS VREF line and several of the sensors would be shared with the stock ECU.

Matt ,

Thanks for your reply . From your explanation , means MS don't simulate another set of signal which will cheating ecu . Correct me if i am wrong . That's mean all output signal to injector and ignition will be controlled by MS and ecu no longer control them . No check light will pop up if do so ? Mind to share wiring diagram that show MS act like piggyback ? Sorry for asking so much question .

Matt Cramer · Post by **Matt Cramer** » Wed Mar 07, 2007 8:59 am

Yes, the ECU will not control the function any more. Whether a check engine light will occur, and how to get rid of it if it does, will depend on the ECU.

Norbit · Post by **Norbit** » Thu Mar 08, 2007 8:33 am

Matt Cramer wrote:Yes, the ECU will not control the function any more. Whether a check engine light will occur, and how to get rid of it if it does, will depend on the ECU.

Thanks matt .
I guess my current car ecu should be not that intelligent to know ignition and injector no longer under its control . Unplug injector and ignition to see whether check engine light will occur , Is that good idea ?