zhertec

Pretty new to all this, but basically I've installed gen 2 PnP on a stock 1998 miata (Aus dm if that matters), with MAF disconnected and using stock IAT with the appropriate values. The car will crank fine, but doesn't catch/start at all.
Tune is pretty much the base map (v3.3a) with some basic values adjusted (as per intro guide).

I hope the logs are correct as well..

Any idea what could be wrong? I haven't messed with any startup/idle settings cause I've heard the base map is decent. Also when cranking, rpm is detected and synced.

Wideband is a AEM 30-4110

Thanks!

StanTheMan

have you confirmed
do you have spark?
do you have petrol ?
and assumption you have compression ...ie nothing sinister going on with the belt.

zhertec

Using the spark and injector test mode, I think I have both. Since the car runs fine which switched back to the stock ecu, I can safely assume the timing on the belts should be fine?

Dildo

Does it start when you give it a little throttle? I noticed the TPS signal was at 0% in your log. If so you might need to increase idle cranking duty to give the car more air while cranking. It is most definitely not your timing belt, but once you get it started you should set the base timing.

zhertec

Even with throttle the car doesn't start, maybe once in a while you can hear it catch very slightly, but then it'll just resume cranking. I've tried increasing crank pulse with no luck as well.

I've attached some more logs with longer cranking and throttling a bit.

Dildo

It's possible that there might be too much fuel. There is a "flood clear" setting under cranking/startup that lets you pick a TPS % where it will stop sending fuel to clear a flooded engine.
Try setting that above 70-80% and floor it while you are cranking.

Also I noticed you have untimed injection turned on. I'm not sure about your miata, I didn't even know a 98 existed. But it should be wired up as sequential already.

zhertec

I've tried cranking during flood clear (at 100% tps) and making sure there was no signal on the pulse width gauge, and I think I've tested it with sequential timing (using DIY autotune's settings on a 99 miata), but also with no avail.
I've also pulled the plugs and they seem to be a bit rich (black and slightly moist looking) so I'm fairly confident there's fuel going in?

Could it be my crank timing and fixed timing is so completely off? I.e. should I just trial and error offset or these values until it (hopefully) fires up?

Dildo

I am a little confused because you say it's a 98 but I never knew that model year existed. Is it an NA or NB? And how did you verify spark?

zhertec

It's essentially a 99 nb8a, but the build date/vin just says 98. Base model with a bp4w 1.8l.
Spark was confirmed in test output mode (as well as during cranking) with a timing light.

Small update: I've checked the timing for fixed advanced during cranking and with a 4 degree offset it reads pretty close to 10, so timing should be ok? Besides that in the logs I've noticed a lost sync 31/32 error during cranking which apparently means cams are not seen (but composite log shows both crank and cam signal?). I've also increased the cranking pulse and ASE and VE tables for idle. Once in a while it will very slightly attempt to catch but then go back to cranking.
Another setting to consider is my trigger is on "rising edge" and spark output is on "going high", from doing some reading braineack recommended it should be on falling edge? or am I pulling things out of context?
Either way I'll have to wait a while since my battery is dead from cranking like 100 times

zhertec

Update: Attempted to change ignition input capture to falling edge, but I couldn't achieve optimal timing after playing around with trigger angle offset.

In spark testing mode 4/1 and 2/3 both give out spark according to the timing light, and there is also spark during cranking. (Although oddly I couldn't actually see spark when I cranked/tested while the plugs were out? EDIT: Realised this was probably because they weren't grounded)

I've tried playing around with increasing fuel in VE tables and both priming/cranking pulse with no avail. Batch timing was also switched to seq. injection with same settings as these (since same model): https://www.diyautotune.com/support/...ial-injection/

Cam/crank signals look fine? (4 blue per 1/2 green) with no sync errors (red).

If anyone has an idea why it won't start (just cranks forever with no slightest attempt of catching/turning) I'd greatly appreciate it as I'm dying to get this started after 2 weeks of disappointment

Just a note: Everything works perfectly fine when the stock ecu is plugged in.

Holdor

If it tries to catch with a bit of throttle, and the plugs are wet, try increasing your idle cranking duty steps at whatever your coolant temp is. If you are cranking in flood clear, it still won't start as it turns off the injectors so you can burn off extra fuel in the cylinders.

I'd also lower your cranking rpm to 350-400.

Have you watched the newb friendly tuning guide by Pedxing that are stickied? I found them really helpful in diagnosing my own issues on initial startup.

zhertec

I've tried increase both idle cranking duty, but it will still only just start to catch but die and continue on cranking. And yea I have been skimming through Pedxing's videos, but so far no luck :(

Also I've mistakenly said my engine is a bp4w, but apparently ausdm got a bp5a engine along with a different cam, but it shouldn't differ too much right?

zhertec

UPDATE: IT STARTS!! After dropping the cranking dwell to 6.3 ms and spark dwell to 1.2 ms it fired up after a bit of cranking .

The only issue is when it leans out and dies after ~15 seconds of idle, and also it stalls instantly when any throttle is added (accel enrichment issue I think?).
Another thing that worries me is that the values in my VE table are a lot higher than most (70+ in the idle area). I know the values are relative, but should it be that high? I basically bumped the basemap up like 2-3 folds almost.