ls1 24x crank signal inverted? (sync errors 68 and 91)

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linuxman51
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ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by linuxman51 »

I've been digging around for almost a week now and am search-deficient or something, and the new manual layout isn't really helping the cause either. :RTFM:

Ms3x on a V3.0 board, firmware may be a little out of date but no more than around 6 months (if that matters)

Anyway, got a 24x setup on a 05-06 5.3 v8, with an aftermarket cam (not sure if that's pertinent, but thought I would mention it in case it was). Car was previously running with a 24 tooth base wheel and single tooth cam wheel from an optical sensor, and for that I replicated the hall/optical input circuit for the cam input.

I am re-using the inputs on the ms (they do not have any pull-up resistors nor are there any caps), as per documentation the ls1 sensors are hall with an internal pullup. At a glance the signals looked great, but I couldn't get it to sync up in coil on plug mode. It will crank and run in wasted COP mode (runs fairly well actually, with almost zero tune, but I've almost come to expect that over the years. it's probably pig rich), and won't throw any sync errors in the datalog. I flipped the triggering edge in the software, but that didn't do anything but cause errors on every single hit of the crank wheel.

I feel like I've missed something obvious but I can't seem to figure it out. I've attached composite logs (one where there were no sync errors, after messing with it for 10 minutes I took the log and of course it doesn't act up that one time, but the signals are the same, and one with the edge flipped where it's a veritable sea of red).

I think the msq is 'right' in terms of triggering (it's currently set to wasted COP, which is what it runs with), the old setup was a high-ish boost 4 cylinder, so don't pay too much attention to the ancillary things, I've not gone through and turned everything off/down for the new setup yet. (actually, I can't open the msq to verify this at work, it's either set for wasted COP or seq.)

I didn't grab a datalog on the way out this morning, but the one that corresponds to the 3-10-18.47 csv was a solid line of error 91 with erratic spots where it would briefly register cranking rpms (< 1s)
12 years of ms-ing things up..
607whp volvo 740 (ms3pro)
1994 volvo 940 turbo L33+7875+ms3x
Matt Cramer
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by Matt Cramer »

How is it jumpered for RPM input?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
linuxman51
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by linuxman51 »

it's configured for hall input on both cam and crank sensors. crank is run in on the tach input circuit, jumped to opto, with caps removed and diodes jumped per the assembly guide. When I was using the optical input the cam and crank circuits had pull-up resistors on them, I removed them on both circuits for the LS sensors.
12 years of ms-ing things up..
607whp volvo 740 (ms3pro)
1994 volvo 940 turbo L33+7875+ms3x
jsmcortina
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by jsmcortina »

Using the opto input might work, but I've only tested the LS stuff wired up as per the manual using the VR/universal circuit.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
linuxman51
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by linuxman51 »

it's a hall/optical sensor, right? why wouldn't you use that input? (curious.. not being rude)

I used the vr inputs in the past with the optical sensor on the previous engine configuration and it caused a number of oddball (but not datalogable directly) issues that did not go away until I switched both inputs to hall. I'd rather not go back down that road if I don't have to.
12 years of ms-ing things up..
607whp volvo 740 (ms3pro)
1994 volvo 940 turbo L33+7875+ms3x
jsmcortina
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by jsmcortina »

The opto-isolator input is designed for slow tach signals from the coil-negative. The LS1 decoder requires an accurate tach signal and the universal ("VR") tach circuit is better for that.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
linuxman51
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by linuxman51 »

interesting.. I didn't have any problems with it up to the upper 6000's with the previous 24 base single cam trigger. It still doesn't seem to have a problem with that(altho I've probably only rev'd it to maybe 5500), it just appears to be upside down.
12 years of ms-ing things up..
607whp volvo 740 (ms3pro)
1994 volvo 940 turbo L33+7875+ms3x
linuxman51
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by linuxman51 »

went to get new info last night (well, updated info), switched back to sequential and coil on plug, hit the key and the car cranked right up, no errors at all. We were troubleshooting what's turned out to be a bad brand new thermostat, so I just jacked with the idle settings while it heated up (and then went hotter than it should while the hoses and radiator remained cold).

let it cool off for about an hour, hooked the downpipe up to the exhaust, cranked right up again only this time it had a persistent error 68, but only one sync loss.

no wiring changes or anything like that (I was going to swap in the jbperf 2.1 board that I've got sitting around, and might still).
12 years of ms-ing things up..
607whp volvo 740 (ms3pro)
1994 volvo 940 turbo L33+7875+ms3x
linuxman51
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Posts: 213
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by linuxman51 »

installed a jbperf dual vr board v2.1 and bypassed the onboard opto inputs, and the problem seems to persist- at least from the appearance of the composite log I took this morning (which.. looks identical to previous ones), and the failure to sync on the first crank attempt this am.

datalog shows a steady error 68 for the duration of the datalog but no sync loss or dropouts or anything else like that. what gives? The only thing changed setup-wise from the first MSQ is flipping between coil on plug and wasted coil on plug.

No external pull-ups on the inputs.

I can't currently post the composite log or msq, (sneaker-net not allowed)
but for ignition options I've got:
spark mode - LS1
trigger angle - 0
skip-pulses - 1
ignition capture - rising edge
spark out - going high
number of coils - COP
spark hardware - MS3X
cam input - js10 (nothing is wired up on the ms3x cam input)
Flip polarity on high-res tach/cam 'normal'
12 years of ms-ing things up..
607whp volvo 740 (ms3pro)
1994 volvo 940 turbo L33+7875+ms3x
jsmcortina
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by jsmcortina »

Why not follow the instructions in the manual? They are known to work.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
linuxman51
Experienced MS/Extra'er
Posts: 213
Joined: Sun May 02, 2004 2:55 pm
Location: Montgomery, AL
Contact:

Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by linuxman51 »

I don't trust the onboard VR stuff having had less than desirable results in the past running logic level signals into it.
12 years of ms-ing things up..
607whp volvo 740 (ms3pro)
1994 volvo 940 turbo L33+7875+ms3x
jsmcortina
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Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by jsmcortina »

I'm sorry, but you are on your own then.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
linuxman51
Experienced MS/Extra'er
Posts: 213
Joined: Sun May 02, 2004 2:55 pm
Location: Montgomery, AL
Contact:

Re: ls1 24x crank signal inverted? (sync errors 68 and 91)

Post by linuxman51 »

Not surprising. 8)
12 years of ms-ing things up..
607whp volvo 740 (ms3pro)
1994 volvo 940 turbo L33+7875+ms3x
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