Megasquirt help!!

volospian · Post by **volospian** » Tue Jun 10, 2014 4:32 pm

Technically it produces a 12v signal, but I know what you mean. I'm just saying that, as far as MS setup is concerned, it shouldn't be treated like a hall sensor. The manual suggests that if you set the MS up as if it is connected to a hall sensor, it won't work. It also suggests that if you set it up as a VR sensor it won't work either. It should be set up as a hybrid between the two.

Interestingly, I believe that if it were a Gen IV (e.g. LS2, LS3, LS7) using the 58X setup, it should be set up as a standard hall sensor, but not for an LS1 (or LS6, L33, etc.)...

*shrugs* all I can say is that the signal was wildly unstable, with no appreciable switch point on the comp log (i.e. randomly changing up and down) and only showing a "correct" cam signal for maybe 10% of cranking duration, whatever I did with the MS. Then I loosened the sensor, at which point, without altering the MS setup, it became about 90% stable with good solid switch points in the trace.

Have a look at my MSExtra thread and compare the composite logs to see what difference it made.

DaveEFI · Post by **DaveEFI** » Tue Jun 10, 2014 11:10 pm

volospian wrote:
DaveEFI wrote: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":-)

So sorry for trying to help you. I'll know better in the future.

stevieturbo · Post by **stevieturbo** » Tue Jun 10, 2014 11:17 pm

volospian wrote:Technically it produces a 12v signal, but I know what you mean. I'm just saying that, as far as MS setup is concerned, it shouldn't be treated like a hall sensor. The manual suggests that if you set the MS up as if it is connected to a hall sensor, it won't work. It also suggests that if you set it up as a VR sensor it won't work either. It should be set up as a hybrid between the two.

Interestingly, I believe that if it were a Gen IV (e.g. LS2, LS3, LS7) using the 58X setup, it should be set up as a standard hall sensor, but not for an LS1 (or LS6, L33, etc.)...

*shrugs* all I can say is that the signal was wildly unstable, with no appreciable switch point on the comp log (i.e. randomly changing up and down) and only showing a "correct" cam signal for maybe 10% of cranking duration, whatever I did with the MS. Then I loosened the sensor, at which point, without altering the MS setup, it became about 90% stable with good solid switch points in the trace.

Have a look at my MSExtra thread and compare the composite logs to see what difference it made.

The 58x as they call it...60-2 for normal people is a more conventional trigger pattern with just a single track of teeth. As said, the 24x is just bloody weird.

Surprised Matt, Denmah ( sloppy mechanics ) or any of those guys cant just supply a map file that would work. The trigger setup shouldnt require any effort at all. They've all done LS engines now with the MS platform, Matt is even offering wiring loom kits as well now.

stevieturbo · Post by **stevieturbo** » Tue Jun 10, 2014 11:18 pm

Out of interest...

have you actually tried to start the engine, or only just testing at cranking speed ?

Will the engine run ?

volospian · Post by **volospian** » Wed Jun 11, 2014 8:41 am

DaveEFI wrote:
So sorry for trying to help you. I'll know better in the future.

sorry if I caused offence. I was only having a laugh.

The trouble is that while the issue is either the signal or the conditioner, there are a myriad of variables that can cause a problem with either the signal or the conditioner.

The signal could be a faulty sensor, incorrect wiring, an incorrect gap or interference from a bad solder joint, bad connector, the starter motor itself, a bad connection at the starter or at the battery, battery voltage, noise coming into the ECU from the other earth points, etc. or, as stevie has just mentioned, the quality of the signal at low rpm.

The conditioner could be affected by the pots set incorrectly, bad components, bad firmware, incorrect settings in the tuning software, incorrect pull up setting and probably other areas.

Troubleshooting is then very difficult when, considering just one of those variables, various people (not on this forum, i might add) say things like "the voltage at zc testpoint should be 2.5v" and someone else says it should be 2.0v, and yet another says it should be between 1v and 2v... so you end up just chasing your tail half the time, especially when, I suspect, the actual final voltage at zctestpoint will depend entirely upon the installation.

I do appreciate your assistance and I know, in theory, this should be a fairly simple issue to resolve, assuming nothing out of the ordinary is happening elsewhere, but, after a month of fiddling with r11 positions, the closest I have to a stable trace is when I pulled the sensor away from the cam by half a mil.

So, I'm sorry if I saw the funny side to your post, and I'm sorry if my "taking the mick" offended, but at the moment, if I don't laugh I'll cry

volospian · Post by **volospian** » Wed Jun 11, 2014 8:48 am

stevieturbo wrote:Out of interest...

have you actually tried to start the engine, or only just testing at cranking speed ?

Will the engine run ?

No, you're right, this is at cranking speed. I haven't tried to start the engine yet as I was aiming to get somewhere near a relatively stable signal before I tried starting it. Besides, I thought the ECU would only try and fire the engine when it had a sync? I wasn't getting a sync for more than a split second until I moved the sensor...

I have been wondering whether the signal would stabilise once the rpm rose above the 150-170rpm or so that I get under cranking.

stevieturbo · Post by **stevieturbo** » Wed Jun 11, 2014 8:56 am

The good thing about hall sensors is their signal will be good at low rpm.

Not that it helps much at the minute. It does sound a crazy amount of faffing about for somethin that should just work.

volospian · Post by **volospian** » Wed Jun 11, 2014 9:24 am

It's really frustrating as I was expecting lots of little snagging issues to be required, but as far as I can tell, everything else, coils, injectors, sensors, fuel delivery, oil pressure, is fine. If only I could get this frikken cam signal nailed I think I'd be there.

stevieturbo · Post by **stevieturbo** » Wed Jun 11, 2014 10:19 am

And ecu dependent, yes the engine would be able to run with crank trigger only. The cam or phase reference is only essential for fully sequential operation, or if the crank trigger has no unique markers for tdc.

DaveEFI · Post by **DaveEFI** » Wed Jun 11, 2014 10:23 am

stevieturbo wrote:The good thing about hall sensors is their signal will be good at low rpm.

Not that it helps much at the minute. It does sound a crazy amount of faffing about for somethin that should just work.

They will often read when stationary. No reason why they shouldn't. That's why I suggested rigging up an LED - if you just turn the engine by hand (or crank it) you should see it go on and off as it passes a tooth.

What seems to be causing a great deal of confusion is what type of sensor it actually is. As MS tends to refer to VR or hall or whatever to try and keep things simple. At the end of the day it matters not one jot what the actual sensor is - all that matters is the waveform it produces.

stevieturbo · Post by **stevieturbo** » Wed Jun 11, 2014 2:07 pm

It is a hall sensor. It produces a digital square wave.

DaveEFI · Post by **DaveEFI** » Wed Jun 11, 2014 2:36 pm

stevieturbo wrote:It is a hall sensor. It produces a digital square wave.

Any more info? What is it peak to peak? Does it swing from approx +12v to zero?

volospian · Post by **volospian** » Wed Jun 11, 2014 5:14 pm

Oh I do not fekking believe this... I thought I'd try and start it up, but now the fpr is not working. It was fine last time I connected it.

If I ground 85 manually, it comes on, pump runs, etc.
If I go into test mode, connect the multimeter between the fpr wire and a 12v feed, go into test mode and click "pump on" the voltage goes up to 12.5v and drops to 0v when I click "pump off".
However, when I click "pump on" and connect the fpr wire to pin 85 the voltage drops to 0v and the relay stays dead.

I thought the fpr was a switch to ground? When I ground the relay manually it works so it's not a duff relay, and when I just test a route to ground on the fpr it shows voltage... it just won't drive the relay any more. This was working before I started f*^king around with the ms.

Arrrgggghhhhhhhhhh........

volospian · Post by **volospian** » Wed Jun 11, 2014 5:17 pm

By the way, when I said fpr I was referring to the fuel pump relay, not fuel pressure regulator

stevieturbo · Post by **stevieturbo** » Wed Jun 11, 2014 6:52 pm

DaveEFI wrote:
stevieturbo wrote:It is a hall sensor. It produces a digital square wave.
Any more info? What is it peak to peak? Does it swing from approx +12v to zero?

I had a scope trace saved somewhere ages ago, cant find it now. 99% sure it was either 5v or 0v, although the sensor is still 12v powered.

It isnt a swing, it's a hall/digital signal, simply either off or on.

The actual upper/lower limit wouldnt really matter much. Just set the trigger thresholds at say less than 1v or higher than 4v and anything beyond that would be covered.