[rusEfi] Miata NA 1990, 1.6L stock #21

[Dial0]

Looks like the AFM fuel pump switch is purely mechanical. So the ecu shouldn't effect it.

It really sounds like the fuel pump isn't running when cranking from what you described.

You manually activate the fuel pump by opening the vane. It builds up a bit of fuel pressure in the rails. Then you crank and because the fuel pump isn't running you get a couple puffs before the fuel pressure in the rail drops.

If you can find a way to short out the afm switch, by pushing a paper clip into the connector or something, you can rule it out as a problem then.

[AndreyB]

I've just got my 1991 running, I had to change the trigger shape to get it running - there was nothing you could have done, but once firmware 20160614 gets to the build server you should be good. I cannot explain why your or my car did not run while the blue one did, and your 1996 has the same sensor, and the yellow festiva has just started using the miata NA sensor -

Note how on this picture it looses sync and then gets it back and then looses it again? That's because the trigger gap width ratio, the value I am using to sync, was just a bit outside of the magic expected range of 1.11 to 1.86. I was unable to start my car until I have widen the sync detection gap to from 1.04 to 1.86, and that's something you cannot do via TS - that's the trigger shape definition source code. Posting my tune to my 1991 thread in a second.

Sorry for all this and thank you not giving up. With three 1.6 Miatas active we will rock this place!

[tomiata]

Ok great. Congrats on #20. I'll try new firmware tomorrow!

It's weird, I never saw it do that gap in timing before. Maybe it's intermittent?

[AndreyB]

a less charged battery or more charged battery could be making a difference? no idea.

[tomiata]

Another day, another Miata running rusEFI!

I picked up the latest firmware and applied @russian's tune for a rough timing and fuel map. She started!!

[video][/video]

Still need to get TPS set up correctly, idle control, etc., but it starts now. Thanks for the help guys!

[puff]

congrats! what's up with cranking, guys? no idle valve connected?

[Dial0]

Sweet, good work!

Did you do the same as russian and use the stock ecu to warm up the engine? or were you able to start it from cold?

[tomiata]

That run was semi-warm. I first tried it warmed it up on stock ECU and it failed. I realized two hours later that my swapping out tuning files disabled injectors.
Engine had cooled to about 104F. I tried again just now cold (87F in Texas), and it started up easily. Still runs pretty rough though.

And no idle control hooked up yet. I'll work on IAC, WBO2 input and MAP next.

[AndreyB]

cold (87F in Texas)

30C for our metric friends

[AndreyB]

Still runs pretty rough though.

I have a confession to make. Also good news and bad news:
We've both started our engines on two cylinders. Injector outputs were not configured right - should be PD3&PE2. But we did it!

[tomiata]

Yes, it did seem that I was not running on all cylinders.

After changing the injector outputs, I'm running much smoother. I also enabled MAP and WBO2 inputs today, and I leveraged @thommm's smurf tune.
Now running very smoothly!

[video][/video]

[AndreyB]

Did you say fan control? I believe our cars do not use ECU for radiator fan control - this Miata has three coolant sensors, one of them is the radiator fan switch I believe?

[tomiata]

Oh, there is a coolant thermal switch and ECU can control fans also on pin 1R.

miata1990coolingfans.jpg (22.03 KiB) Viewed 17152 times

[AndreyB]

Ohh, so two ways to control the fan - I did not know it!

[tomiata]

I now have idle control, map, tps, speed density tuning settings based on @thommm's smurf tune, and I drove about 20 miles on it testing and running TS auto tune. It's running very well now. Thanks, Thommm, for sharing the tune!!

It is still running rich at idle and a little rich overall. And, I get an occasional hesitation or miss is notiable when cruising at about 60mph and I noticed it once when accelerating from a stop. I haven't noticed it at idle. Any ideas on that?

Also, there is a smell of gasoline after driving. And I have a carbon monoxide alarm in the garage, and it has gone off a few times after working on the car. If I run with the garage open for a while, then stop, close the garage and go inside about 10 minutes later the CO alarm goes off. I thought it might be from emissions not enabled. Does that sound like need to enable purge solenoid?

[kb1gtt]

I'm not sure about CO sensor, I expect the purge evap is usually to prevent gasoline vapor emissions, which I would expect would not trigger the CO sensor.

Occasional hesitation could be failed spark. If spark is too far advanced, backing the timing off by half a degree or perhaps a degree might fix that. It might also be worth checking your spark plug gaps, make sure the plug wires are in good shape, and clean out carbon build up with something like sea foam.

Hmm how does it turn off? Does it cut fuel and keep sparking? If it cuts spark, then it would likely dump some extra fuel in the exhaust. I forget what the exact sequence is for when it shuts off. However I doubt you would be able to smell that. I would wager a guess that it's running rich, and you have un-burnt fuel in your exhaust. Do you have a way to verify your WO2 accuracy? Those can easily be incorrect if they are not installed in the exhaust pipe in the correct location and such.

[AndreyB]

I get an occasional hesitation or miss is notiable when cruising at about 60mph and I noticed it once when accelerating from a stop. I haven't noticed it at idle. Any ideas on that?

Yellow car sometimes has misses on idle, too. Sometimes its five minutes without a miss, sometimes it's two misses in a minute.

Half of the times these are visible as an AFR spike on the log. Do you have an SD card to use on the ecu for logging? Need more data.

[tomiata]

Yes, I do have an SD card on the board capturing logs. I didn't watch closely enough when the hesitation happened. I have a video from some of the testing and I put it together with a capture I did of the TS gauge view I got from @thommm, I don't see an afr spike when I think the hesitation happened.

[video][/video]

I'm out of town until the weekend and I'll look at it more then...

On the gas smell, it could be running too rich, and I''ll check spark plugs. I don't have a way to verify WO2 accuracy. I did the calibrate according to instructions. It's from innovatemotorsports.com.

[AndreyB]

What are some timestamps with hesitation?

[AndreyB]

I am tempted to make rusEfi console have a feature to upload & share your current config every time you start it...

[tomiata]

One time I noticed hesitation is in the video just after 1:28 after shifting to 5th gear. You can see the spikes in AFR when I shift, but after shifting to 5th there are two more little spikes. It seems like it was more than just those 2 or 3 seconds though. I'll do more testing on Saturday after I get home.

[Abricos]

((two more little spikes )) unburned fuel ...
misfire near 2800 - 3000 RPM ???

[Thommm]

I have the exact dame misfire at those RPMs, and occasionally at around 2000-2200, I've been playing with the timing a lot, backing of by many degree's, got slightly better but not fixed yet. I've checked timing and checked my map against some megasquirt guys, it's not very advanced anywhere up to above normal/stupid levels. What I did find was that it sparked quite weak, but it was just as weak on the stock ecu, running on brand new plugs. The coils aren't that powerful on Miata's but the stock ecu can do mostly without misfires (occasionally at low rpm, high load).

I also haven't been able to figure out automatic idle control, I can control the valve with the slider so it works, but it's not responding to the automatic mode?? Tried inverting pins, didn't fix it

[kb1gtt]

Is the problem when at that RPM, or perhaps when you have a rapid RPM change, or perhaps when you have a rapid throttle change? I ask because it might be a wall wetting issue. If it happens when you do a rapid long pedal change, it could be that more fuel needs to be injected to wet the wall, such that what goes into the cyl is proper. Keep in mind that your O2 sensors is reasonably slow, so it might not change fast enough to show some lean for a engine rotation or two.

[AndreyB]

How do we figure this misfire out?

Yellow car has occasional misfire just idling for minutes. Both with distributor and with individual COPs. They are now trying to record the signals with a logic analyzer to see if that's on the firmware end or not.

I will record a continues idle and continues 3k idle this Saturday to see if I have the same issue myself, but first I need to tune idle fuel. http://rusefi.com/forum/viewtopic.php?f=5&t=1047 is to some extent a prerequisite for this investigation.

[Thommm]

I've tested alot to try and fix the misfire, it does it under all circumstances, no change in throttle (accelerating) large changes and decrease in throttle with tps disabled. Also dumped in more fuel and pulled timing, nothing fixed it. The mis at 1800-2200 is occasional and is not at a fixed rpm, the 3300 is very steady. Could indeed try hooking up the scope to the trigger signal and capture data while at 3300 RPM

[AndreyB]

the 3300 is very steady. Could indeed try hooking up the scope to the trigger signal and capture data while at 3300 RPM

I will run @ 3300 with http://www.ebay.com/itm/New-Set-USB-Logic-Analyzer-Device-USB-Cable-24MHz-8CH-24MHz-for-ARM-FPGA-/291457642276 on Saturday - this case I would see both trigger and outputs.

[kb1gtt]

I believe you can set an input as a trigger, then the analyzer will record before and after that event by a certain amount of time.

[Dial0]

Hmm interesting, would be good to see throttle position as well as the ignition timing angle in the video.

There isn't any sync loss with the crank trigger?

If its possible it would be great to have a graph of engine acceleration.
That way any negative spikes in that graph would correlate to a missfire, then you can pinpoint the missfire and the conditions around it.

I would be great to be able to see the engine sniffer console output and that tuner studio data log along side each other.

[AndreyB]

I would be great to be able to see the engine sniffer console output and that tuner studio data log along side each other.

unfortunately rusEfi own engine sniffer does not support continues operation - these are relatively short snippets, like ~500 events per screen.