Sunday, March 13, 2016

Ignition, Sequence...START!!!! Engine is running!

A small step for mankind, but a gigantic leap for Salt Slush Racing was taken today 4pm when our race engine fired up ad sang its first song.  When we past this milestone Salt Slush and Friends were more than happy!!
The Salt Slush N3T based race engine first real start.

But as always, there's a before and after.Before the engine started we double-checked everything twice, called in friends, and googled our way forward, but we just went deeper and deeper in to the well known Garage Depression.
Mattias came with good tuning ideas. Still, no start...
Magnus, Anders and Mattias did their best to create combustion...which mostly happened outside this combustion chamber...
As a consequence, we started to protect our ears more carefully.
Then Per showed up with his expensive (now justified!) digital oscilloscope. Tada! We doublechecked the crank sensor tree times and Yes, we found the problem! 
For those who don't know...this is how it feels when the Garage Depression, suddenly goes away. It coincidently happened when the combustion moved back in to the engine.
Anders, Ragnar, Magnus and Leif, all happy as kids on Christmas Eve.
Cina, here dressed in her Sunday best, also cheered up significantly! 
Computer Geek Equipment Disguise revealed.  The oscilloscope's home; A bag from Marimekko...By the way, this picture of P.A was taken after the engine started.

The problem?

And, if you wonder, what was the issue? And, what was the solution?

The symptoms we have had the whole week was that it started nicely while in "crank mode". It reved up and ran sporadically for at most a few seconds. 

We double checked everything twice! We tried all sorts of lean/rich mixtures and strategies - Speed density, Alpha N (which had the record running time of 8 seconds) We tried with an without cam sensor, new battery (which helped a lot).  We exercised all our collective engine knowledge for the whole week and weekend.  Everything seemed in order, but still no cigar

Until... when we hooked up an oscilloscope to the cam, crank, injector and spark signal.
Then the problem appeared in daylight.  With the scope we could see that ignition timing was good until the engined got some rev. Then the ECU lost its concept, and started to fire seemingly at random. 

This picture is after the cure and is what it should look like.

We have crank signal, 60-2, in yellow on top. Cam signal on bottom in blue, spark in purple and injector as light blue. All in harmony.

When it failed spark got out of sync with cam, and crank. 

The source of the problem and the solution?

The crank sensor!

We switched it to a hall sensor. And on the very first try it just fired op and ran perfectly on lambda 1. 

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