Sudden rough running [resolved] - Page 16 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 05-08-2009, 10:04 PM   #301
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Originally Posted by TravisR View Post
How are they doing anything with peak and hold then?
So if they were low impedance, say 3 ohms, then peak-and-hold would hit them with full path to ground, unregulated, and generate a peak 4A+ of current, for a brief period of time to get them opened. I=V/R=12/3=4A. It would then go into current limiting mode, to whatever the current limiter is set at, to hold them open.

With the high impedance injectors, though I noticed a difference when I turned on and off peak and hold (with the correct injector dwell settings loaded), it was not much. I just had to tweak the cells a bit. So IMO with the high impedance injectors it is not doing much at all. Before with the 'wrong' injector dwell map it would die when peak-and-hold was turned off. Peak-and-hold must be adding a little bit of dwell to the pulse or something.

In fact, here is the deal. I got home (not in the Miata) and set the current limit to max, 1.9A IIRC. I started the car, and it ran normally. I then turned off peak-and-hold. It stumbled a bit but not much. I tweaked the AFR a tiny bit, and played with the idle settings. I took it out for a drive, did some pulls, drove it back home, parked it, and let it idle with the a/c, lights, stereo, etc. all turned on. It idled... and idled... and idled... and idled... for about 20 minutes. No problems. There were some slight variations in RPM, but very slight, like 100 rpm or so.

Watching the Ecu Data window, I did see some current indications in the 1.0A range. It happens quickly, and not every injector cycle. But that is only because the injectors and the telemetry are not cycling at the same frequency so you have to watch and wait for them to coincide. That tells me that indeed the injector can pull more than 0.9A of current, so the current limiter could very well have been causing the problem.

So, once again, I am not ready to declare victory yet. But it looks good so far. Stein I would recommend setting your current limit to 1.9A, and turn off peak-and-hold. You might have to tweak your map a bit and your idle settings a bit.

And now, a caveat for future newbness...

THIS MAX CURRENT SETTING DISCUSSION ONLY APPLIES TO HIGH IMPEDANCE INJECTORS!!! DO NOT MAX OUT THE CURRENT LIMIT IF YOU ARE RUNNING LOW IMPEDANCE INJECTORS!!! DO NOT GET PISSED AT ME IF YOU FRY YOUR LOW IMPEDANCE INJECTORS! IF YOU DO NOT KNOW WHAT I AM TALKING ABOUT, GET HELP.
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Old 05-08-2009, 11:20 PM   #302
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OK, I did it. It took a full 30% master fuel trim to get it back to a reasonable level. It looks like it has some merit. I had been playing with idle air and fuel while it was warming up and it got better in spots.

I think that I have to do the full idle tuning from scratch again. Too many things have been jacked with.
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Old 05-08-2009, 11:33 PM   #303
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I wonder why my ECU didn't have the same problems as yours though... I beat the crap out of my car trying to get the same situation and it never happened. The peak and hold makes perfect sense now. Thanks Tex!
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Old 05-08-2009, 11:39 PM   #304
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Nice work Tex!

Kudos to you, Stein and Travis.
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Old 05-08-2009, 11:53 PM   #305
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No premature celebration! Oh man, you guys jinxed it for sure now!

I just went for another spin and it is still running fine. No rough spots, nada. I really need to work on my tip-in enrichment though. That is next.

Stein my idle settings need to be adjusted as well. I changed them a bit here and there to get me going but I probably should go through a retune as well, open-loop then closed loop like before. For example I need a LOT less post-crank idle effort than before (in the open-loop settings). At one point I had it up to 6 or 7. When I started the car a little while ago, that was way too much and it immediately revved to like 4K. I shut down the motor, backed it down to 2 or 3 and that was plenty on the next restart.

Watch your AFRs closely, especially under boost. I had to add in some injector dwell in the upper parts of the map.

I really, really hope this is it guys. Until after I drive it to and from work a few times next week, I'm not ready to declare this solved. But, buena suerte otra vez!
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Old 05-09-2009, 12:00 AM   #306
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I just base tuned mine with idle air at max=0. Had to crank out the idle air screw a bunch again. It was idling at 850 at the start. It had been idle air screw tuned before at 980. You probably would benefit from a full idle tune as you and I have both made a bunch of changes that likely masked some problems with compensations.

On another topic, did you have to add a bunch of fuel across your whole map?
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Old 05-09-2009, 12:07 AM   #307
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Quote:
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I just base tuned mine with idle air at max=0. Had to crank out the idle air screw a bunch again. It was idling at 850 at the start. It had been idle air screw tuned before at 980. You probably would benefit from a full idle tune as you and I have both made a bunch of changes that likely masked some problems with compensations.

On another topic, did you have to add a bunch of fuel across your whole map?
OK thanks for the info.

I definitely had to add some fuel pretty much everywhere. Not an extreme amount, but some. Not to the point where it would not run, but where the AFRs were 0.5 to 1 point too high and it needed some fuel to get it down again. I selected all the cells and marked them as untuned and allowed adaptive tuning to adjust them, mostly the mid range cells. The idle cells I tuned by hand; I have them excluded from adaptive tuning with the min RPM setting.

The boost cells needed some fuel added up at the 12-15 psi range. I trimmed those by hand too; as soon as I saw the AFR climbing, I backed off and added some fuel by hand. The map trace feature came in handy there. I could see exactly which cells I had just run in, and thus knew where to add the fuel.
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Old 05-09-2009, 12:19 AM   #308
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Quote:
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The boost cells needed some fuel added up at the 12-15 psi range.
When we get this whupped, you need to do a little writeup on how to install the EBC on the Adaptronic for us short bus riders.

I'm bored with 7 psi already. Plus, I have a farmer friend that thinks his 98 Camaro Z28 vert will take me. He said no way he would lose to a 4 cylinder ricemobile. I don't want to beat him, I want to humiliate him.
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Old 05-09-2009, 12:32 AM   #309
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The EBC installation is no problem. I'll try and do a write up on one soon, or at least the way I did it. BTW all I am doing right now is open-loop control, tuning it the same way I did on the MS. Also, I have a high-pressure wastegate, so I am just using the EBC to get me to 12-13 psi fast, and letting the wastgate take it from there.

But, when I get to the dyno, I'll be (carefully) aiming for more than 15 psi and will use the EBC to raise the peak pressure over the wastegate. When I ran it on the MS, I had a 7-8 psi wastegate and used open-loop EBC to get me to 14.

You need to humiliate that Z for sure. If it is stock, that is what, like a 13 second car? You might need a bit more boost
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Old 05-09-2009, 11:58 AM   #310
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Well crap. Did everything all over, retuned idle from the start, redid fuel tables, road tuned via rapid learn, stopped for gas and the same damn thing. Got home, shut it off and restarted a few minutes later and it kept surging and dieing.

Even after the saturated and 1.9A. Also, I did adjust the Cam 720 to Crank 360.

One common theme-again, the fuel trim is pegged at 3%. It just doesn't move at all as the car is surging, the injector pulses are moving, idle and AFRs all over the place. It just sits threre at 3%. It has to be part of this problem at least for me.

Trim works fine when the car is cold, or at least when it hasn't been parked hot.
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Old 05-09-2009, 12:11 PM   #311
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Alright Stein I'll get them on the phone Sunday (Monday their time) and see what I can find out.
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Old 05-09-2009, 12:14 PM   #312
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Damn... OK I'll try to take my car for a spin when it heats up today and see if I am still having the same issue. I do not think I am having the same trim problems you are though IIRC.
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Old 05-09-2009, 11:09 PM   #313
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OK Stein is right. That did not fix it. I had the same problems again, though it seemed to be a bit more robust. There was still a strong correlation with heat soak, with the a/c making it worse as usual.

But, I have two suggestions. One is a band aid, the other is a possible fix.

1. Use the 'Recovery RPM' feature in the closed loop idle settings. I got aggressive with mine, like 15 at 700 RPM and 25 at 500 RPM or something like that. It seems to help keep the car from dying, although it may still run poorly if you load it (try to drive away). At least it will help keep it from stalling completely.
2. Per Y8S' suggestion above, change triggers 1 and 2 from FALLING edge to RISING edge.

Here is the deal with #2 above. I was out driving around, having problems again, tried lots of different things, but could not clean it up completely. I had given up, was driving home, and remembered the rising edge suggestion. I figured what the hell, I'll give it a try. So I set both triggers for rising edge and the car still ran. So far so good. Did some pulls, car ran the same. Still good.

Then I tried something else. With the car heat soaked, sometimes while accelerating I would get these bad hesitations like spark blowout or the boost limiter kicking in. With falling edge I was getting these while driving home. When I switched to rising edge, they went away. I switched back to falling, and the hesitation was there. I switched to rising, within just 3-5 seconds (had it all set, just had to hit apply) and the hesitation went away again. Back-to-back, it cleared it up.

I had to get home and could not go heat soak it in traffic again. But, Stein, it is worth a try if your car is still messing up.

My guess is the heat soak is doing something to the trigger sensors. They are after all both right on the front of the engine in the direct path of the radiator heat blast.

It makes me wonder... Does the stock ECU use rising or falling edge? I'll have to go search for this.

NO MOTHERFUCKING DECLARATIONS OF VICTORY YET! IT IS BAD MOJO!

Last edited by ZX-Tex; 05-09-2009 at 11:21 PM.
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Old 05-10-2009, 10:46 AM   #314
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Could you try putting a ziplock bag of ice on them and see if it makes a difference? Glad to hear you fixed it again.
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Old 05-10-2009, 11:14 AM   #315
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The ice would work with the cam sensor, but I'll be happy to let YOU try that with the crank sensor on a running motor Freeze spray would be a better idea.

It would be even better yet to get an oscilloscope on the outputs of both sensors and watch what happens to the signals as they heat up. The heating could even be accelerated with a heat gun.

I am going to take the car for another drive today running some errands. I'll report back later. On another note about switching to rising edge, the other variable that changes slightly would be the timing, presumably advanced a bit. But, guessing from the wiring diagram, Trigger 1 (reluctor 1?) is the crank sensor; the trigger tooth on the pulley is very narrow, much narrower than the 'teeth' on the cam sensor. So I doubt the advance is substantial, and the timing map is conservative anyway.

Last edited by ZX-Tex; 05-10-2009 at 11:24 AM.
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Old 05-10-2009, 03:58 PM   #316
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OK drove it around this morning and noon, in traffic and on the highway, full A/C, with no problems so far. MAT and CLT were both well above temperatures where I have seen problems before. It is idling in the driveway right now and I am going to let it keep idling.

On another note, has anyone had problems with their PC locking up while running WARI? It could just be my laptop...
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Old 05-10-2009, 05:31 PM   #317
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Seems like mine used to do that before I updated the drivers for my RS232 convertor. It would lockup when I was logging and just disconnected it before I stopped logging. I haven't had that happen in a while. I'm also running vista.

So we have a 2 part problem with the tuning then. The injector driver, and the reluctors...
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Old 05-10-2009, 05:41 PM   #318
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search miata.net for the AEM on an NB thread with JasonC SBB and emilio700 posting in it. there should be some scope traces of the rising/falling issue.
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Old 05-10-2009, 05:54 PM   #319
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Thanks for the search tip. I just started reading the thread but I think it is this one
MX-5 Miata Forum - AEM on 99 - 00?

Ah no wait, here it is, linked to in the above thread
http://forum.miata.net/vb/showpost.p...9&postcount=39
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Old 05-10-2009, 06:51 PM   #320
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So all that you changed is switching falling to rising on Trigger 1? Nothing else was changed? Likely going to be trying this tonight. I need to so some more idle air and fuel smoothing anyway.

Are you still running your car as Current at 1.9A and unchecked peak-hold?
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