I've been driving my car for the last 6 months with an obvious electrical problem...I know about patience.
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Lol
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Originally Posted by richyvrlimited
(Post 760897)
Some region cars do, not all. That baro map sensor isn't always populated.
So I can pretty much guarantee that as barometric pressure increases, you are going to see an increase in fuel PW and a decrease in spark timing at all operating conditions, because an increase in barometric pressure will cause an increase in computed load.
Originally Posted by Reverant
(Post 760912)
switching between the stock ECU and a MS to measure the parameters I am sending (CLT, IAT, RPM).
Or you could always do a parallel install on the bench. :D |
Yes, it is a 2Ch 60Mhz scope. I am using both channels to correlate the injection timing (one probe on NE, one on the injector) and the ignition advance.
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Thanks reverant for finding out this information.
Hopefully this info leads to better understanding of what the stock ecu does for startsup and other conditions. |
Originally Posted by Reverant
(Post 760983)
Yes, it is a 2Ch 60Mhz scope. I am using both channels to correlate the injection timing (one probe on NE, one on the injector) and the ignition advance.
If your multimeter does frequency counting, you can use that instead, and not even have to bother adjusting the scope's timescale. |
Any new nuggets of wisdom extracted from the stock ECU? :)
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Yeah, the stock ECU fires the injectors half the times the Megasquirt does, and that fucked up everything that I've measured so far, concerning the injectors. I need to figure out how to get the MS to fire the same number of injections as the stock ECU.
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Originally Posted by Reverant
(Post 768020)
Yeah, the stock ECU fires the injectors half the times the Megasquirt does, and that fucked up everything that I've measured so far, concerning the injectors. I need to figure out how to get the MS to fire the same number of injections as the stock ECU.
How very odd, almost like simultaneous injection on the MS, with 1 squirt per cycle? |
When you said the ECU adjusted idle by altering advance, what ranges are we talking here? Thanks ;)
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Originally Posted by richyvrlimited
(Post 768022)
this still the early 89-93 ECU i.e. batch?
How very odd, almost like simultaneous injection on the MS, with 1 squirt per cycle? Still on the 89-93 ECU. I also have a 94-95 ECU to play with, but no stim for that year yet. |
Originally Posted by Greg G
(Post 768024)
When you said the ECU adjusted idle by altering advance, what ranges are we talking here? Thanks ;)
Btw that was the main reason why I decided to go for a full standalone setup. |
altered the baro sensor pressure and seen any results?
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Originally Posted by Reverant
(Post 768027)
Exactly. It does half the injection events, without about twice the pulsewidth.
Still on the 89-93 ECU. I also have a 94-95 ECU to play with, but no stim for that year yet. |
1 Attachment(s)
Originally Posted by Reverant
(Post 768020)
Yeah, the stock ECU fires the injectors half the times the Megasquirt does, and that fucked up everything that I've measured so far, concerning the injectors. I need to figure out how to get the MS to fire the same number of injections as the stock ECU.
Rooting around on my hard drive, I found the following scope trace, which I must have taken on a running car, given how ugly the INJ pulse is: https://www.miataturbo.net/attachmen...ine=1315332142 My notes say that this is the INJ 1/3 wire, but that's about it. What bugs me is the filedate- this picture claims to have been taken in 2008, and I'd have already been running a Megasquirt by that time. Maybe the date got corrupted in a file copy operation... But yeah, there's clearly only one injector shot per engine cycle here. At moderate to high load, I would think that the MS's two-shots-per-cycle would, in theory at least, produce slightly more even fuel distribution, as each amount of fuel will spend the same length of time "lingering" in the port regardless of which cylinder it is on. At idle, however, it may well be that the stock ECU's method is superior, as one shot of fuel can be more precisely metered than two half-shots. Alas, this capture was taken at idle, so perhaps the stock ECU switches to two-shots-per-cycle at some higher load condition? Can you test for this? |
Originally Posted by Techsalvager
(Post 768062)
altered the baro sensor pressure and seen any results?
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Originally Posted by soloracer
(Post 768082)
I can't WAIT for the 94-95 ECU info. Which ECU do you have; there were 2 in 95 in the U.S. IIRC.
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Originally Posted by Joe Perez
(Post 768159)
Alas, this capture was taken at idle, so perhaps the stock ECU switches to two-shots-per-cycle at some higher load condition? Can you test for this?
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Originally Posted by Reverant
(Post 768180)
I can't with the onboard baro sensor. At least not someway I can think of, I couldn't see a port on it somewhere.
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2002 ECU. Look at the funny injection sequence - semi batch or something?!?!? It is fully batch below 500rpm - but only during the first cranking event. Above 500rpm this is what you get:
It goes like this: 1-2 1-3 4-3 4-2 Oh and y8s...alternator no chargy below 300rpm. |
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