INJ -signals are inverted in µP

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simis
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INJ -signals are inverted in µP

Post by simis »

Hello,

I have Megasquirt V3.0 and daughter card Megasquirt 2 installed in quite old second hand unit. I added injector driver board (just duplicated existing one) and no matter what I do voltage in FET -driver inputs are inverted. It is 0V when power is ON, it is pulsed to high when engine is cranked. So it is quite obvious that engine is flooded pretty much instantly. Also even if I change settings in Tuner studio from standard drivers to additional drivers voltages are same. Even when I change to standard drivers also those additional drivers get inverted voltages.

So what I should do? I have tried this with 3 latest firmware 3.4.2, 3.4.1 and 3.4.0 .

I measured those signals with scope. During firmware loading signal state changes but as soon as it has loaded it it stucks to GND.

Should I change injector drivers to non-inverting models? Everything else is working, all sensors can be calibrated and spark is OK. VW wasted coilpack.

Thanks,

Simo
Matt Cramer
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Re: INJ -signals are inverted in µP

Post by Matt Cramer »

:msq:
Matt Cramer -1966 Dodge Dart slant six running on MS3X
simis
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Re: INJ -signals are inverted in µP

Post by simis »

Here is msq file.
billr
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Re: INJ -signals are inverted in µP

Post by billr »

You say this is "old second hand", did the standard drivers work properly before you installed the additional ones? Are all injector drivers "stuck" on now?

Changing the type of transistor isn't the logical way to fix this; that would be masking some kind of assembly problem on the unit, a problem that might bite you in some other ways as you proceed forward.
simis
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Re: INJ -signals are inverted in µP

Post by simis »

I bought this several years ago and guy told me that it is "OK".

So if settings are batched injection all 4 injectors operates, but in inverted.

If settings are sequential all operates same way as batched injection.

Firing order is 1432 and injectors are opening now :
1 and 4 same time and 2 and 3 same time. I thought that they should open all in different time if sequential mode.

I de-soldered FET-driver off and measured resistance from µP pin to GND and it is 20k. I think that there are for some reason internal pull-down resistor ON. In spark outputs resistance is over 8M.

Should I replace processor or is there any way to see is that output broken or not. I hate to pay 150€ for new board if this can be solved with some software thing.
racingmini_mtl
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Re: INJ -signals are inverted in µP

Post by racingmini_mtl »

The issue is not a software/firmware issue. You have added some hardware in a way that seems to ignore what should be done. The software is designed to work with the standard hardware and with the correct settings. If you want to use the modified mode with additional drivers, you need to use the correct hardware modifications and drivers and configure the settings accordingly.

You seem to be doing random things with the settings and using drivers in a non-supported way. You need to state explicitly what hardware you have and what you have modified and added. And using the standard drivers in a sequential mode with additional drivers is never going to work without significant modifications; you need to be able to understand the schematics and the needed modifications before attempting this.

Jean
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simis
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Re: INJ -signals are inverted in µP

Post by simis »

My opinion is that it has now nothing to do with HW. If there are no components in processor pin, why it has 20k resistance to GND? That is the issue now. If my settings does not make any effect how processor pin behave how that can be HW issue?

Even if I remove extra drivers INJ1 andINJ2 signals won't work properly.

I know that a lot of people has make this work and there should be no problem in SW. Just asking if someone else has seen this kind of problem.
racingmini_mtl
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Re: INJ -signals are inverted in µP

Post by racingmini_mtl »

If your opinion is that it's not the hardware and we know that the firmware works as it should then you're on your own. As I said, explain exactly what you did on the hardware side if you want help on this. The only reason I can think of to have an inverted injector signal is if you have done a bad hardware modification on the injector drivers (and this has been the case in a few cases in the past).

Jean
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simis
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Re: INJ -signals are inverted in µP

Post by simis »

I have added same parts as in http://www.megamanual.com/ms2/pcb.htm this schematic to INJ3 and INJ4 pins, except fly-back components. Otherwise it is standard.

I could understand that if my added components broke INJ3 and INJ4 but also INJ1 and INJ2 are inverted and I have not done anything to them, except now removed drivers and pull-ups to see if problem is there.
racingmini_mtl
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Re: INJ -signals are inverted in µP

Post by racingmini_mtl »

There is no INJ3 and INJ4 in that manual. You need to use the MS2/Extra manual (linked at the top on the page) and completely ignore the megamanual. The link you need is this: http://www.msextra.com/doc/pdf/html/MS2 ... .4-55.html (section 4.10.4)

You must have see this at some point to talk about INJ3 and INJ4 so you may also have made other modifications. You need to make sure you either have all the correct modifications or none at all. And, as I said, you need to use the proper settings. Give as much information as possible in your posts because this is becoming tedious. Post pictures of your setup where we can actually see the details of the hardware.

Jean
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