MS3pro '90 1.6 dying
 

I'm posting in here since this might be an MS problem. Car's been sitting for a year. When driving it'll suddenly lose power, wideband will continuously blink at 10afr, and then die. It has a very difficult time starting. During cracking it will blink 10afr. The only way to actually start is by flooring gas pedal. Even then, after multiple tries, it idles at 200rpm. At 200 rpm, even if gas is applied, engine does not respond. Eventually it will idle normal. Spark plugs after inspection smelled like fuel. Plugs and battery replaced with new ones. Seems to happen more with uphill driving but may be in my head.

The car drive perfectly fine for a year prior before it got hit on the side and I replaced rear subframe.

Any ideas? I'm afraid to get a log BC I'll be stranded. Don't want to get my neg hole pozzed.

A data log and MSQ would be very helpful. If you're afraid of being stranded, can you duplicate the problem idling in your driveway?

It doesn't die while idling. The idle was rough though (would rev high then low, high then low) until I changed to a new battery.

While it looks like the VE and spark tables could use some work, nothing's jumping out from the tune file. I'll need a data log to see what's going on.

I was able to get a data log (attachment) today. There was a lot of RPM oscillations. I revved it a couple times to recreate some of the stumbling/sputtering I was getting at idle, too. Hopefully the idle issue is the same issue that is causing the engine to die while driving.

Thanks for taking a look.

BTW: car is 1991 1.6 bone stock other than the MS3pro.

its idling really lean even with 26% extra fuel from warmup enrichments.

you should calibrate your battery voltage so it matches the voltage you see at the injectors. im going out on a limb and saying they aren't at 13.4v when running.

Have you calibrated your wideband recently? Maybe your readings are way off...
Your idle MAP seems awfully high- even for a pretty wide open idle valve.
What injector dead-time are you using?

Injector dead time is 1.2ms

Joe P was the previous owner. This is what he told me through email when I first got the car.

The wideband O2 sensor is connected to the MS, but it's not doing anything. The narrowband sensor is what's actually active. I converted the narrowband to a four-wire, but it's functionally equivalent to a one-wire. I would suggest that you remove the wideband (uego) altogether and throw it away. It's a piece of shit and is horribly mis-calibrated. I only used it for the initial coarse-tune, and then switched to the narrowband.

What could cause this disparity if it was not an issue before? A tune that was done on a dying battery?

the msq loaded doesn't look that bad. it should have you idling well.

that's what makes me think other mechanical issues are afoot.

Agreed. It appears there is some sort of misfire happening at idle that is not clearly tied to any ECU output. But make sure you're on the latest firmware as well.