I am running:
MSII v3 board
tried all firmware
car:
'83 280zx turbo
optical crank angle sensor
I am having a problem with a loss of power at 5000rpm and 6000rpm. I have had this problem off and on since I have owned the car, before and after the megasquirt install. Looking at datalogs, I can't see anything that would cause the loss of power (AFR, MAP, dwell, advance...) My guess that the problem lies in the optical crank angle sensor, since this is the only remaining sensor from the stock setup.
Question,
Is there any way to data log the input to the megasquirt from the crank angle sensor? I am curious to see if the signal is degrading at high rpm causing the megasquirt to fowl up. The problem definatly seems ignition related. Thanks!
-jeremy-
dataloging crank angle sensor output?
Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
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Bernard Fife
- Super Squirter
- Posts: 1009
- Joined: Mon Feb 16, 2004 3:15 pm
Jeremy,
Did you disable the spark retard rev limiter? By default it is set to start retarding at 5500, with full retard at 6000, and a retard of 12°.
I'm not sure what you mean by logging the crank sensor angle. This is a user input (trigger offset) not an output. So MegaSquirt assumes that whatever you enter is correct, and has no way of verifying that because there are no other inputs that MegaSquirt could compare it to (though you can do it with a timing light).
Lance.
Did you disable the spark retard rev limiter? By default it is set to start retarding at 5500, with full retard at 6000, and a retard of 12°.
I'm not sure what you mean by logging the crank sensor angle. This is a user input (trigger offset) not an output. So MegaSquirt assumes that whatever you enter is correct, and has no way of verifying that because there are no other inputs that MegaSquirt could compare it to (though you can do it with a timing light).
Lance.
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jsmcortina
- MegaSquirt Guru
- Posts: 332
- Joined: Mon May 03, 2004 12:34 am
- Location: Birmingham, UK
- Contact:
The MS1/Extra code has a feature to log the tach input,
( http://megasquirt.sourceforge.net/extra/triggerlog.html )
but this doesn't help you with the MS2 at the present time.
This feature will almost certainly make it into MS2/Extra at some point.
James
( http://megasquirt.sourceforge.net/extra/triggerlog.html )
but this doesn't help you with the MS2 at the present time.
This feature will almost certainly make it into MS2/Extra at some point.
James
My Success story http://www.msruns.com/viewtopic.php?t=8008
MS1/Extra at: http://www.msextra.com/manuals/MS_Extra ... _Index.htm
MS2/Extra at: http://www.msextra.com/ms2extra (runs on MS2 and Microsquirt)
MS1/Extra at: http://www.msextra.com/manuals/MS_Extra ... _Index.htm
MS2/Extra at: http://www.msextra.com/ms2extra (runs on MS2 and Microsquirt)
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Bernard Fife
- Super Squirter
- Posts: 1009
- Joined: Mon Feb 16, 2004 3:15 pm
Jeremy,
Ah, okay, I understand now - you want to log the raw tach input.
There is a bit of a problem with this - the raw signal is heavily filtered in most cases before reaching the processor, so the raw signal isn't available to log (though the processed signal is). In most cases, the rpm field *is* the result of the processed input signal (incl. both hardware and software filtering), though this isn't necessarily the case for missing tooth wheels.
I suppose a bright spark could use a spare ADC pin (of which there aren't many extras) to log the raw wheel signal, though the sampling rate whould have to be very high to see anything, and as a result the datalog frequency would have to be very high as well. (At 5000 rpm, and a 36-1 wheel, you have a 5000/60*36 = 3000 Hz signal.) So I suppose it's posible, but definitiely not trivial.
In the end a good timing light signal that matches the MegaTune display and a stable rpm in the regular datalog will suffice for most people, most of the time.
Lance.
Ah, okay, I understand now - you want to log the raw tach input.
There is a bit of a problem with this - the raw signal is heavily filtered in most cases before reaching the processor, so the raw signal isn't available to log (though the processed signal is). In most cases, the rpm field *is* the result of the processed input signal (incl. both hardware and software filtering), though this isn't necessarily the case for missing tooth wheels.
I suppose a bright spark could use a spare ADC pin (of which there aren't many extras) to log the raw wheel signal, though the sampling rate whould have to be very high to see anything, and as a result the datalog frequency would have to be very high as well. (At 5000 rpm, and a 36-1 wheel, you have a 5000/60*36 = 3000 Hz signal.) So I suppose it's posible, but definitiely not trivial.
In the end a good timing light signal that matches the MegaTune display and a stable rpm in the regular datalog will suffice for most people, most of the time.
Lance.
lance,
Thanks for the great replies. I have double checked the timing with a light and it seems to be dead on. To make it easier, I changed all of the values to 15 so that it would remain constant (easier to see fluctuations) and it stayed within a degree or two. The thing is, I can only check that when not driving and I do not experience any percievable problems with the car in neutral. Under acceleration though the problem persists.
I have changed the rev limiter to 7000rpm (redline for this motor) and changed it to fuel cut instead of spark retard.
The trigger wheel has six notches, one for each cylinder and the output on a scope is a really clean square wave pattern. I would check this out again on the scope, but I do not have access to it anymore
Also the scope might not display the problems easily if there is random pulses missing from the signal.
My thoughts are that I might be experiencing some radio interference in the signal wire coming from the distributor. At high load high rpm (when spark is more intense and frequent), the signal becomes messy. This might explain why I am not seeing it in neutral. A datalog of what the megasquirt is seeing might prove to be useful.
The next thought is that the direct coil driver cuircuit only puts out 7amps (I am directly driving the coil through the msII) and this is not enough to provide a hot spark. Has anyone else had any problems with the coil driver not providing enough current to fully saturate their coil? I have messed with dwell and spark duration settings and seemed to have found a happy medium of the settings. .9ms duration, 5ms max dwell Changing the duration either way seemed to decrease performance.
The most frustrating part of the whole bit is that the problem isnt' always there. I had one day where the car pulled very strong clear up to 7000rpm and it felt great. The next day, the car ran as usual with a big power decrease at 6000rpm. I checked the pc board for flux, re-cleaned off what I had missed, reinstalled the firmware, tried different versions, and still have no luck. Otherwise everything is great, but lacking the full power potential of the engine. Thanks for the help, any more would be greatly appriciated. Thanks!
-jeremy-
Thanks for the great replies. I have double checked the timing with a light and it seems to be dead on. To make it easier, I changed all of the values to 15 so that it would remain constant (easier to see fluctuations) and it stayed within a degree or two. The thing is, I can only check that when not driving and I do not experience any percievable problems with the car in neutral. Under acceleration though the problem persists.
I have changed the rev limiter to 7000rpm (redline for this motor) and changed it to fuel cut instead of spark retard.
The trigger wheel has six notches, one for each cylinder and the output on a scope is a really clean square wave pattern. I would check this out again on the scope, but I do not have access to it anymore
Also the scope might not display the problems easily if there is random pulses missing from the signal. My thoughts are that I might be experiencing some radio interference in the signal wire coming from the distributor. At high load high rpm (when spark is more intense and frequent), the signal becomes messy. This might explain why I am not seeing it in neutral. A datalog of what the megasquirt is seeing might prove to be useful.
The next thought is that the direct coil driver cuircuit only puts out 7amps (I am directly driving the coil through the msII) and this is not enough to provide a hot spark. Has anyone else had any problems with the coil driver not providing enough current to fully saturate their coil? I have messed with dwell and spark duration settings and seemed to have found a happy medium of the settings. .9ms duration, 5ms max dwell Changing the duration either way seemed to decrease performance.
The most frustrating part of the whole bit is that the problem isnt' always there. I had one day where the car pulled very strong clear up to 7000rpm and it felt great. The next day, the car ran as usual with a big power decrease at 6000rpm. I checked the pc board for flux, re-cleaned off what I had missed, reinstalled the firmware, tried different versions, and still have no luck. Otherwise everything is great, but lacking the full power potential of the engine. Thanks for the help, any more would be greatly appriciated. Thanks!
-jeremy-