Megasquirt help!!

[DaveEFI]

Dave,

it's a 3.0 board.

I have already done what you suggested regarding adjusting those pots.

I haven't got a Jimstim. I made the mistake of assuming the ms would be similar to something like an emerald, in that a pre built ecu for a specific engine wouldn't need me pulling it apart and fiddling with main board components, or plugging it into oscilloscopes and simulators before I even connect it to my engine.

I feel your pain, but persevere as it's always something pretty simple in the end. 99% down to the installation or a simple software setting. And I'd say you'd have the same sort of problems when doing any self install for the first time, regardless of make. The only safe way would be to pay lots to have it installed for you, by an expert. If you can find one.

[stevieturbo]

For a pre-defined trigger setup, and even more so one with hall sensors...

It really should be a simple task, as it shouldnt require any user input or adjustment.

If doing a trigger setup from scratch, or using magnetic sensors where there are variables, then absolutely it can take some effort to get things working.

The above in itself should mean that the problems here are wiring related rather than configuration.

[DaveEFI]

I'd agree with all of that.

However, MS does require a different pull up resistor between a 5 and 12v hall sensor which has to be added, as the VR input doesn't need one. And of course the wheel decoder software set correctly.

The trigger log showing the pulses inverted is suspicious.

[Cobratone]

Richard, is it worth trying bank fire at first to try and get it running then go over to sequential? At least that way you don't have to worry too much about the cam sensor or do you need the cam sensor for ignition too??

[DaveEFI]

The crank sensor's not producing a reliable signal either by the log.

[volospian]

I may have had a breakthrough... I wondered if there was an alignment issue with the cam sensor, so I tried moving about it a bit and it didn't make much difference, then I wondered about tolerances, so I thought I'd check it and undid the retaining nut a few turns before pulling the sensor up a bit. I got a much better signal, so I pulled it up some more and it fell off again, so I pushed it back down a little and tried again.... now I get something that seems much more like a correct signal.

The crank signal still looks "inverted" compared to the reference trace image that is hanging around, but I've seen other composite logs on working setups that show the same signal as mine, so I'm not too worried about that.

The only issue at the moment is the cam signal seems a bit... lazy. It doesn't seem to quite match up with the crank signal and loses sync every few rotations. Looking at the comp trace it looks like the signal is dropping a little late. I assume this may be that the gap is still not quite there and I may have to work on some shims or something to make this signal better, but, finally, I feel like I may have moved forward a little. If I change to falling edge, the sync goes crazy, so I presume rising edge is correct.

Before I spend hours fannying around with shims, does anybody have any other suggestions as to what may be causing this lazy switch (hysteresis perhaps?).

Cheers,
Rich.

[stevieturbo]

Are you not using all the factory triggers/sensors etc ?

And what do you mean by inverted ? The signal should simply be 0v or 5v. They use hall effect digital signals, either off or on, 0v or 5v.

There is no inbetween or variance.

24x crank signal just looks weird all the time, but still a 0v or 5v range.

[volospian]

Yes, using stock sensors which is why I hadn't thought of checking the gap before.

By "inverted" I mean that the trace is "upside down" when compared to this stock trace:



That is to say that the pattern is the same except where the pattern goes "thin, thick, thick, thick, thick, thick, thin..." etc at the top of this, the pattern is the same at the bottom of mine so the pattern appears... maybe "out of phase" is a better description.

As I said, I have seen other comp logs showing the same pattern as mine that work ok so I'm not too worried about that bit.

[stevieturbo]

The OEM trigger setup has no adjustment. It should never need to be adjusted. What you describe sounds like sensor could be wired wrong, although never actually tried testing one with polarity reversed.

[volospian]

*Shrugs* the cam signal is considerably better now I have raised the sensor by around 0.5mm - 1mm (haven't measured it). It seems what should and what shouldn't need doing goes out of the window with aftermarket customisations. After all, if I had used the gm ecu I shouldn't need to f*^k around with adjustable potentiometers either.

The Crank sensor could be wired with reverse polarity and I'm going to check that but:
A. The cam sensor doesn't work at all with the polarity reversed. I imagine I may see similar issues with the Crank sensor, but it's worth checking
B. As I keep saying, I have seen others running fine with the same Crank trace as I'm currently getting.

[DaveEFI]

Generally, if you have to f**k around with those pots, something else is wrong. Especially with hall effect. Hall effect produces a simple on/off signal. A VR sensor (which the MS input is designed to cope with as well) produces a sine wave of varying amplitude, which does require some conditioning to provide a stable on/off pulse under all conditions to the processor. But even then MS will generally give a stable enough signal to get you going out of the box. Obviously with any sensor the gap between it and the trigger is going to be important.

It should be very easy to prove your hall effect sensor is working correctly. Connect an LED with suitable resistor to it. It should switch from on to off if you move the trigger wheel from tooth to valley. It really is that simple.

[volospian]

The LS1 sensor is neither a hall nor a vr sensor in their truest form and appears to be described in the manual as a "logic module". It requires a hybrid setting between the hall and vr options. This is fully documented in the manual. It is not correct to set up an LS1 sensor as either a hall or vr.

To be fair, I only f*^ked around with the pots because people kept telling me to. However I now find that the best signal I've achieved so far is to set the ms up as per the manual for ls1 sensors and adjust the gap between the sensor and the cam.

[DaveEFI]

Yes - hall effect could well be the wrong name. But as I understand, it produces a sort of logic signal which should be easy to read. ie, a simple on/ off (square wave) which is the easiest for MS to use. Pretty well the same as a hall effect.

It would be good to get a scope across it so see what the actual signal is.

It comes down to one of two things.

Either the signal from the sensor and its electronics that MS is seeing is faulty in some way, or the MS input isn't conditioning it correctly.

[volospian]

It comes down to one of two things.

Either the signal from the sensor and its electronics that MS is seeing is faulty in some way, or the MS input isn't conditioning it correctly.

LMAO... sorry, but I have already worked out that "it's either something to do with ms, or it's something else".

That's a bit like saying "global warming is down to one of two things. It's either man made, or something natural":-)

[stevieturbo]

Regardless of what name some people might want to call the sensor.

It is a hall sensor, it is powered like a hall sensor, and it produces a digital off/on 0/5v signal...just like a hall sensor.

IMO, that makes it a hall sensor lol

The inverted signal is strange, but if it is a regular and stable signal, it should be fine in that respect as an actual signal that can be used.
But if the ecu is expecting a normal LS trigger pattern, then the ecu would not understand this new form as it would be different.

If the ecu doesnt understand it, you risk ignition timing being wrong, or simply not working at all.


It makes no sense whatsover that you should need to be adjusting gaps with a factory setup. ECU used should be irrelevant in that respect, again because the "waveform" is simply off or on. There is no inbetween like you'd see with a mag sensor and true variable waveform and voltages.

Factory sensors, gaps, wheels etc would produce perfectly good strong usable signals.

A proper scope trace would be handy to see what is actually coming from the two sensors