MegaSquirt Type 3 Project

[WFC]

I'm using this sensor from DIY Auto: http://www.diyautotune.com/catalog/hall ... p-489.html



And here's a photo of where it's installed:

[Max Welton]

Very neat.

Max

[Steve Arndt]

I spy a 009 :p

[WFC]

I spy a 009 :p

Nope... That's the stock FI Distributor. I do have a oo9 that I will be using, but it's been gutted and locked.

[WFC]

OK, I got the engine to run with the trigger wheel. At first it was missing and running rough. I reduced the gap between the sensor and the tips of the wheel and the engine smoothed out. It also starts up quicker with the trigger wheel compared to the stock points. With a more accurate ignition, I also had to lower my timing. So all is good, except for one big problem...

I can't rev the engine past 2500 rpm! When I go above this, it starts missing and chugging. I tried adjusting the dwell settings - no improvement. I made sure that the rotor aligns with the spark towers (remember I'm running a locked distributor). I double-checked that the timing on the engine matches the ECU. The only thing I suspect is the sensor alignment...

When I drilled the hole for the sensor, the sensor ended up a little bit off-center. Would this cause the trouble I'm having? Could the sensor work at lower RPM but not at higher due to misalignment? It's an easy fix, but I want to make sure my problem isn't caused by something else instead.

As always, THANKS!

[Max Welton]

Is the timing advancing with the RPMs?

Max

[WFC]

Yes the timing is advancing properly. All the gauges in TunerStudio are reading normal.

The more I think about it, I'm certain that the sensor alignment is at fault. I'm also wondering if the sensor shouldn't be mounted perpendicular to the trigger wheel? Does the sensor typically need a larger metal surface to pass by it? Maybe the edge of the wheel is too small?

[supaninja]

You can watch the tooth logger while your reving it, if the height of the signal drops down then it's trigger wheel moving away from the sensor. also if it's not concentric you'll see the tooth signals doing the wave lol.

[WFC]

Woo Hoo! Realigning the trigger sensor fixed the problem! And what an improvement in performance! The engine accelerates very smoothly compared to before.

Now I get to fine-tune the ECU to run even better!

[Piledriver]

Once you get it working you will never miss your distributor, ever.

[supaninja]

^ the truth

[WFC]

After this morning's great advancement with the trigger wheel and sensor, I went to the post office to find that my alternator kit had arrived. Yeah! So this afternoon I install it, only to find that the engine now runs like crap! It doesn't want to start as easily as before, the idle is rough, and response is "angry" for lack of a better word. Why would this happen?

With the alternator, I now get 13.5 volts at idle at the coil and battery. With the generator, it was below 12 volts. So obviously things were under-powered before. TunerStudio showed that the engine was running lean at idle, so the increased voltage caused the injectors to squirt less? I'm also guessing that the fuel pump is putting out more pressure as well. So, I enriched the VE table and got the engine to idle better, but still not as good as with the generator. The AFR reading was around 13.5. If I leaned the fuel out from there, the idle would get worse. Before, the idle was happy around 16 AFR.

So, I'm thinking that the injector settings need to be altered? I'm running low impedance injectors from a 1.8 Mercedes Benz. Here are my settings in TunerStudio:

Injector Dead Time @ 13.2V(ms)= 1.000
Battery Voltage Correction(ms/v)= 0.180
PWM Current Limit(%)= 18
PWM Time Threashold(ms)= 1.0
Injector PWM Period(us)= 66

So, if running voltage has increased, which setting(s) need to be changed to compensate?

Another thing about the alternator is that is makes a whistling sound. Is this normal?

[Piledriver]

So, if running voltage has increased, which setting(s) need to be changed to compensate?

The EFI should automatically compensate well, but the WBO2 was likely misreading with low voltage.
I'd disregard any previous readings with the low voltage condition.

Another thing about the alternator is that is makes a whistling sound. Is this normal?

Probably, may go away once your battery charges fully.

Set idle mix just like carbs, best lean idle, usually 13.5-14.5:1.
..easier for you as you have a built in manometer. (MAP sensor)

There's a procedure to figure out correct injector dead time on msextra.(somewhere)
It matters, esp. near idle.

I'm running modern/highZ injectors, can't help you with PWM settings, I'd start with the defaults.
(My injector drivers are hardware PWM, but working with highZ injectors it just passes along the PW)

[WFC]

Setting the current limit to 30% and voltage correction to 0.200 seems to have fixed the issue. I didn't have time to drive it, but at idle I was able to get the AFR back to around 16. This afternoon I should be able to do a test drive.

I know most people are using high-impedance injectors, so this is not an issue for you, but what are optimal settings for low-impedance injectors? If raising the current limit from 18% to 30% improved things, would raising to 40% improve them even more? All the manuals say is that higher levels may result in over-heating the injectors.

[WFC]

My test drive went well this afternoon. I let VEAL make the adjustments and everything seems to be running great. Speaking of VEAL, I read that you need to disable acceleration enrichment when using it. Is this true? It would seem that TunerStudio would be aware of when the enrichment is active and ignore readings at that time.

I still need to dial in my cold start settings. Right now, the engine will fire up after 3-4 revolutions but will die shortly there after. A second start usually stays running. And during that time, you can hear RPMs cycle about 4-5 times before smoothing out. I'm also using the AAR to provide more throttle air when cold. Anyone want to share their start-up settings?