Car flatlines rich at 5k and recovers?

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AbeFM
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Car flatlines rich at 5k and recovers?

Post by AbeFM »

Minor thing, but possibly related:
In the log mon.xs, at 564,5 seconds, you can see pulse width nearly doubled, followed by a cough the whole car felt. Pretty weird. This was after a short period of constant throttle and gently falling MAP.

The "main event"
At 716 you can see RPM take a small dive (input circuits? It's hopefully another topic, though the timing error is very small, inconsistent with the times I have had input issues) what's weird, and this exact thing happened before (in the other log file) where it goes pig rich (not quite full scale, but darned near it), makes very little power and stays for a while. In the earlier scale, it stayed for a while (I was in traffic and just wanted not to get run over). This was only 8 seconds, but in the other log it was quite long, and even occasionally came out of that state only to return a few points later.


Is this a software thing? I was thinking it was an injector sticking, but why does it always start at just above 5,200 rpm and why does it "fix" itself?

This is a miata, turbo (but I don't think boost is an issue) with used Lancer Evo injectors (fairly new), running MS-IIxb18. Thanks!
-Abe.
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hassmaschine
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Post by hassmaschine »

sounds like an EAE tuning problem to me - what are you using for accel enrich?
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Post by muythaibxr »

if EAE were the problem (unless he has some really crazy settings starting at that RPM), it would most likely do weird things across the board...

Ken
AbeFM
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Post by AbeFM »

More or less all my settings in accel enrich are defaults, and all the eae stuff is off. It is port injection, and for it to stay loaded with fuel for 30 seconds seems a bit ridiculous - at minimum I would expect to see things go rich slowly.

I also don't know what's going on with the RPM tapering off like that.

Any ideas for tests I could run?
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AbeFM
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Post by AbeFM »

I was thinking my issue was entering into ASE on these weird events I'm seeing, but checking the log didn't back that up. It shouldn't drop into cranking anyway, should it?

Well, anyway, I did see bit 8 turning on and off a lot, all I could find in the (updated today?) megamanual for MS-II was this:
Note that the datalog includes an 'EngineBit' field. This bit will tell you if the engine was accelerating, warming-up, etc., and can be used to sort unsuitable data lines (because O2 correction is not active under acceleration, warm-up, etc.) from the file.

The enginebit has 7 binary bits. The rightmost bit represents running. It is 1 if ready to run, zero if not ready, so 000001 = 1 or 000000 = 0. The next rightmost value is for cranking, 000010 = 2 if cranking. The fields are:


Binary Bit Decimal Meaning
000000X 1 Ready
00000X0 2 Cranking
0000X00 4 Start-Up enrich
000X000 8 Warm-Up enrich
00X0000 16 TPS accel enrich
0X00000 32 Decel enlean
X000000 64 MAP accel enrich
What is bit 8, then? On the bottom of the screen in MLV I see:
Crank/ASE/Warm/Run/Accel/Decel/Bit7/Bit8, and bit 8 sees a lot of action when my car is acting up.
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AbeFM
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Post by AbeFM »

I'm totally stumped on all this. I think not having fast logging might be much of the issue? Unlike my past issues, where I would get a data point of zero RPM, this is much faster, really the only thing to be consistantly off is AFR's.... But I wonder if I'm not missing a single tooth.

I have been changing resistor values, and it makes a difference, but it doesn't fix things. I can vary the rise time from a few us to a couple hundred ns, but it doesn't fix it.

The weirdest part is it going rich and staying there - I have NO IDEA where that comes from, and I never saw it before with the previous betas. I'm not sure I've seen it with this beta.

Any ideas??!? In the mean time I'm going to build the OEM inputs, though I really don't expect them to help. 33k pull up is pretty small, and will cause a large delay on the sensors.
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Post by Peter Florance »

AbeFM wrote:I'm totally stumped on all this. I think not having fast logging might be much of the issue? Unlike my past issues, where I would get a data point of zero RPM, this is much faster, really the only thing to be consistantly off is AFR's.... But I wonder if I'm not missing a single tooth.

I have been changing resistor values, and it makes a difference, but it doesn't fix things. I can vary the rise time from a few us to a couple hundred ns, but it doesn't fix it.

The weirdest part is it going rich and staying there - I have NO IDEA where that comes from, and I never saw it before with the previous betas. I'm not sure I've seen it with this beta.

Any ideas??!? In the mean time I'm going to build the OEM inputs, though I really don't expect them to help. 33k pull up is pretty small, and will cause a large delay on the sensors.
Certainly appears that it's an RPM problem of some sort.
I wonder if it would be worth using an MS1 chip and megatunix to check triggering (hardware check).
If you do, be sure to disconnect the +12V connection to the 40 pin socket.
Peter Florance
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AbeFM
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Post by AbeFM »

It does sound cheap enough. Does MegaTunix allow you to get at the individual pulses? The MS-II does record that info, the time for each tooth, but James or Ken said it was too hard to get to. Same with the high speed logging, it does it, but apparently there's no way to have it run longer than a second, even if you turn down the number of samples you are taking to compensate.

Today I put it in 3rd going down a GOOD steep hill, and it revved to redline, though I got a nasty bakfire when I lifted at redline, but I don't know if that's because it wasn't firing in the 5k range, or if it was just poor handling of the sudden lift at high RPM.

So far the only REAL clue is that bit 8 flashes on and off all during and just preceding the times when the car acts weird. I've been swapping component values like mad.

I built an exact duplicate of the OEM input trigger circuit, so I will try that next. Thanks for the suggestions so far! Again, what is it MegaTuneIx does, and will it run my '00 miata?
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Post by muythaibxr »

ready: equ 0 ; 0 = engine not ready; 1 = ready to run
(fuel pump on or ign plse)
crank: equ 1 ; 0 = engine not cranking; 1 = engine cranking
startw: equ 2 ; 0 = not in startup warmup; 1 = in startw enrichment
warmup: equ 3 ; 0 = not in warmup; 1 = in warmup
tpsaen: equ 4 ; 0 = not in TPS acceleration mode; 1 = TPS acceleration mode
tpsden: equ 5 ; 0 = not in deacceleration mode; 1 = in deacceleration mode
mapaen: equ 6
mapden: equ 7

So bits 7 and 8 in the log viewer are 6 and 7 here... and they are MAP accel and MAP decel in the latest betas.

Ken
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Post by AbeFM »

Again, looking through the logs, sample by sample, bit 8 is off almost the entire time, except on the very last "normal" RPM sample, then RPMs drop steadily (not really a spike) and the car goes super rich. There are other, rare, times when bit 8 turns on for one or two samples, under slight decel.

I don't see how that's a circuit problem - Something that tells the car to, um, go rich? I don't know how reliable the guage is out that far, but the wideband doesn't show FULL rich, just very rich, like it's over-fueling by a factor of two. No ASE, and the warm up enrichment is low. The pulse width is also low.

Anyway, the datalog isn't helping me, perhaps some experienced eyes can see something. There's a major event at the manual mark (about a screen back, faster to search for max rpm) and a minor one near the end at one of the last "engine state"s of 137, at time stamp 86717.

There's also an RPM: 0 at 86418 sec. The whole thing is filled with a weird, unsteady RPM signal with "no" timing error. All from 86401 to 86404 seconds (really till 86420 with another event at 86429) is an impossible RPM curve with a timing error of less than 1.0

<edit> Thanks for the bit 8 clarification! Here's the file.
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AbeFM
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Post by AbeFM »

Huzzah!
I set up my breadboarded OEM circuit today, an exact copy of the OEM inputs. It was worse than the circuit before it - at ~4k the motor would fall apart. I think the sensors just couldn't deal with the extra charge in the caps. With that set up, the JimStim would cut out around 8700 rpm - when the propegation delay matched the pulse width it was canceled.

Well, while it doesn't make a lot of sense, I swapped out the big caps for some smaller ones, using the OEM circuit only with 1nf caps instead of 10nf seems to have it working very well. Time will tell if it's perfect or just very good, but it IS working. I have reved the motor to JUST under 7k, and my boost limit of 175 kpa seemed to be the only thing stopping me. I did hit "knock" at 6900 or so, but this is likely improper adjustment of the knocksense. It pulled 6 degrees in under half a second, and stepped down at 1 degree every few seconds till normal. On the jimstim I couldn't get it to lose sync. I don't have the numbers with me, but at the ecu the rise ("fall") times were 50 ns, the delay was 16us for the cam and 12 for the crank, the voltage 4.4V for the crank, 3.4V for the cam. I might have them backwards. With the bigger caps the delays were somewhat longer, and the voltages lower (that I don't understand).

So, now I just have to 1) Drive it a lot, and 2) commit a copy to solder and see if I'm still jinxed when I do something OFF the breadboard.


I'm still really confused why the motor goes so rich after missing. It didn't do that now, when I'd hit overboost or knock "cuts".

Anyway, just putting it out there, for the record. Maybe this should go in the 99+ thread. I'll draw up my final circuit when it's final.
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