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Old 05-02-2007, 05:53 PM   #61
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Jerry, I assume the guy whp's Req_Fuel is out of scope is me :( I'm running RX7 550cc injectors that I had cleaned and flowtested. they actually flow 600cc. A little more than I was expecting :(

I guess that's half my problem then!
Yeah I think it was around 5 IIRC-- not far out, but middle of the 6-15 range is good if possible. Idling 550cc injectors on a 4cyl is going to make each step in VE a big difference in AFR, you should be able to idle them just fine though. I may play with the HiRes code at some point and consider offering it on the MSPNP-- with the Hi Impedance injectors (HiRes doesn't support Low-Z injectors) it could give use much better control of the injectors at idle... time for more experimentation.
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Old 05-02-2007, 06:10 PM   #62
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Highres code gave me a noticeably smoother idle.
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Old 05-02-2007, 06:10 PM   #63
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Yeah I think it was around 5 IIRC-- not far out, but middle of the 6-15 range is good if possible. Idling 550cc injectors on a 4cyl is going to make each step in VE a big difference in AFR, you should be able to idle them just fine though. I may play with the HiRes code at some point and consider offering it on the MSPNP-- with the Hi Impedance injectors (HiRes doesn't support Low-Z injectors) it could give use much better control of the injectors at idle... time for more experimentation.
yeah definately me, I'm at bang on 5 I'll play around with richening the AFR's up and maybe altering the wheelcode settings many thanks Jerry!

I'm also using the High_res code so I guess that'll work a bit in my favour
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Old 05-02-2007, 06:45 PM   #64
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As for the wheel decoder settings-- pic below-- make sure to check your base timing after changing this just in case it moves!

2 or 3 things:

1) You have 2nd trigger active edge: rising. Mine won't start/run with rising, only falling (like IRQ)
2) Your triggers are A=2, B=1, shouln't they be A=1, B=2? How have you wired your coilpacks?
3) You have selected the 025 decoding routine. I've had significantly better results with the 024s9 routine (which is also the recommended for wheels with just a few teeth).

Also, I'm pretty sure that I've tried a rich 13:1 AFR idle and it didn't help (I certainly can't pass smog tests with that AFR). Still, I've had a perfect 14.7:1 AFR with the MS and it's great, until you restart/resync the wheel.

Jim
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Old 05-02-2007, 07:57 PM   #65
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These wheel decoder settings were setup by James Murray-- the guy who wrote the code . He was looking at it and A=1 and B=2 is correct for falling, but he felt A=2 and B=1 with rising trigger is the best way to do this.

025 wheel decoder seems to be working great here....

The stock ECU was at 13.2-13.4:1 at idle once warmed up. I simply tuned my car to idle at the same AFR as the stock ECu idled at and it's idling beautifully...
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Old 05-02-2007, 08:00 PM   #66
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Jim, I'm inclined to think the reset issue is due to the injection order. The MS starts injection on its first tach signal. So for a given piston depending on how you have injection setup (alternating simultaneous etc), it will inject at different points in its 4 stroke cycle. These points change when you reset the ECU and you have no control over this unless you inject every 180 degrees which is 4 simultaneous which ensures that for each ignition event there is an injection event.

My PW becomes too small for anything more than 2 alternating squirts. If you can run 4 simultaneous squirts or better with the injectors you are using, you should see more regularity.

Also, try switching your injectors to 1,4 (bank1) and 2,3(bank2).

I played the reset game until it ran nicely in order to pass emissions at idle.

Give the 4 sim squirts and injector rewiring a try and see if this resolves things.

Otherwise the stock ECU does vary PW at a tested rate (might be open or closed loop, or even closed loop with feedforward - not sure) and timing to a degree in order to maintain smoothness at idle. MS may not be able to do this by design.

Once again, a richer idle solved all my roughness issues.
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Old 05-03-2007, 02:33 AM   #67
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By the way, when I have the problem, I switch the injection back to the stock ECU and all is ok; I switch the IGNITION to the Megasquirt, and the revs bounce all over the place, 600-1200 rpms, like I have lumpy cams. Reset and it is stable.

If the problem affects both the injection and the ignition at the same time, then it's either a config problem (and I've tried EVERYTHING) or a code problem.

Jim

Last edited by Reverant; 05-03-2007 at 03:19 AM.
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Old 05-03-2007, 02:45 AM   #68
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when the revs jump around, how are you controlling the IAC valve?
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Old 05-03-2007, 05:36 AM   #69
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I don't control the IAC valve - the stock ECU still does.
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Old 05-03-2007, 09:07 AM   #70
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I'm heading out of town for a couple days (thru the weekend really) but wanted to ask real quick if you'd tried the updated wheel decoder settings I posted. If it's anything intermittently ignition related that is most likely culprit. You can see why when you map out the wheel-- try it out and let us know....
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Old 05-03-2007, 09:23 AM   #71
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I'll give the new decoder settings a try just in case - thanks Jerry!

Jim
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Old 05-03-2007, 09:25 AM   #72
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NP-- do check your base timing after setting the new wheel settings...
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Old 05-03-2007, 11:21 AM   #73
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Also give my injector wiring and number of squirts suggestions a try. They won't harm but will help in any case.
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Old 05-03-2007, 01:56 PM   #74
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I've not got around to trying the new wheelcode settings, however I have changed the wheel routine to 024 and it seems a fair bit smoother.

I've also richened the idle bins to mid/high 13's and lowered the ignition bins to 10deg (as a stock car I had the base timing at 14 so set the MS there)

My god the idle is better now!

Once I buy myself a timing light I'll try the new wheelcode settings too

Thanks a bunch Jerry! (and Jim and Lex )
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Old 05-05-2007, 10:24 AM   #75
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NP-- do check your base timing after setting the new wheel settings...
Well, I changed the settings per the post above, still no go.

Jim
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Old 05-07-2007, 12:17 PM   #76
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Well, I changed the settings per the post above, still no go.

Jim
Did you richen it up similar to how the stock ECU runs it?
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Old 05-07-2007, 05:49 PM   #77
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Did you richen it up similar to how the stock ECU runs it?
I've tried it - no go. For the records, my 2002 likes to idle at 14.7 very much so - both with the stock ECU as well as with the MS.

Now, let me give you an inside scoop. James gave me a modded version of 029v. I can open up the terminal, and by pressing !!q (or something similar, it has been a while) I can force the wheel to be resynced. Guess what, about half the times that I resync the wheel, the problem goes away. Completely. If not by the first try, it will with the second or third try. So it is CERTAINLY not a tuning/config issue - of that I'm sure.

Jim
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Old 05-07-2007, 07:10 PM   #78
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I've got a '91 so I haven't tested what the '02 idles at on the stock ECU-- but (without verifying) I'm sure that's a sequential injection system right?

I've had another theory cooking for a while here that could be coming into play now... That what could be happening here is related to the use of bank to bank injection and it's relation to which cylinder is preparing to fire-- and richening the mixture will make sure that more fuel is always available helping to avoid any lean misfire situations even if the cause is the phasing as much as anything. That's where I could see sequential helping smooth out idle... and that may be what lets the newer Miata's idle at the leaner stoich mixture. But going back to a bank fire system you may need to go back to a bank fire idle mixture...

Older Vehicles tend to idle richer, it's not just the Miata... LOTS of cars. I honestly can't think of an ODB1 car that didn't idle in the 13's on the stock ECU that I've seen.

Newer cars with sequential injection get a couple benefits from sequential injections... idle quality and emissions. Where do they get that? At least partly from being able to safely and smoothly run leaner mixture, and getting better atomization. Does sequential help under power? Not really, things are turning too fast at that point to spray all the fuel in the cylinder while the valve is open to it still overlaps much like a bank fire setup-- so it's about the same in most situations barring extreme race sequential setups with massive injectors.

So when you go back to a bank fire setup, you may have to expect to tune like the factory did when they ran a bank fire setup.... If one of the main benefits of sequential injection is improved idle and cruise emissions-- that's how they got that, leaner mixtures. Take away the sequential, loose the leaner mixtures at idle. You're back to 13.2-13.4. It's a theory, but it makes good sense to me.

As for resyncing and getting different results each time, you're not just resyncing the wheel decoding, but also which bank is firing in relation to which cylinder(s) are on the intake stroke-- get that out of phase, with a stoich mixture, and it will be lean on certain cylinders and you'll miss. Get it in perfect phase the next time you resync and it runs fine-- rinse and repeat.

Thoughts?
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Old 05-07-2007, 07:25 PM   #79
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Why don't you people read what I am saying - I mentioned this before. The reason it works when you reset is because the MS will trigger injection at ANY spark signal. Depending on your wiring/injection config you will inject AT DIFFERENT TIMES IN THE CYCLE for the cylinders .... some combinations work better than others. This is why you are getting it right at times. The code was designed this way in the MS. The problem is most present at idle due to a lot of factors I mentioned such as low pulse widths and high vacuum conditions.

Run at least 4 simultaneous squirts per 720 degrees and this won't be such a large issue anymore. Also wire your injectors together like this: 1,4 and 2,3. Otherwise you'll just have to run it richer.
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Old 05-07-2007, 07:35 PM   #80
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Yes the 1.8s are all sequential injection i believe, atleast 99+ are.

Lex, i'm pretty sure all of us have our injectors wired 1,4 and 2,3 so that shouldn't be a change people need to make. I wish i could try out your ideas, car is locked up for the next 4 months though.
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