Cold "cold start"

[bdog]

To my surprise this morning my car refused to start. The engine is 2004 USDM EJ257 with drive by cable throttle body from EJ207 running Syvecs S6PNP.

Outside temperature was -16 C or a little bit less.

The engine cranked OK - a little bit slower, but perfectly normal. However, the engine did NOT even try to start. After some useless cranking the battery began slowly to give up, so I hooked my notebook and started SCal. Syvecs read 0(zero) rpm during cranking. I opened Sync Log and crank/cam sensor data seemed fine to me.

The engine jump started easy.

Can you give me any ideas how to fix this issue?

I don't think my battery is dying because in the beggining I had perfectly nice cranking rpm given the temperature outside - my guess would be aroung 180-200rpm.

Thanks!

[pat]

If you look closely at the waveform you can see the problem

There should be a red vertical line every time the waveform crosses the rest voltage, but on some of the excursions there is no red line. This is because the high threshold has not been reached, which prevents a trigger from happening. The cause will be a lower cranking speed due to the cold temp. If you go into the Sensors -> Crankshaft Position -> Crankshaft Posistion Sensor A and edit the High Trigger Threshold In Cranking and drop that down to 0.6V that should do it

Cheers,

Pat.

[bdog]

Thanks a lot, Pat!

I'll give it a try.

[bdog]

Setting "High Trigger Threshold In Cranking" to 0.6 did not work. The car would "start" and then stay at cranking rpm.

I changed "High Trigger Threshold In Cranking" to 0.9 and it seems OK. Today started successfully at -18C.

[pat]

The fact that the car exited cranking RPM when the trigger threshold was raised is perhaps indicative of a small amount of heat getting into the cylinders when it ran at 0.6 volts. Looking at the waveform you posted, I wouldn't expect it to start when very cold again, the positive excursions just aren't high enough, ie they don't reach 0.9 volts, but they do exceed 0.6 volts. Perhaps that was a little too low, BUT if it was unhappy then it would have simply lost sync again and stalled. Sounds like the cold start needs some work, perhaps it needs more air to get up out of cranking RPM...

Cheers,

Pat.