Saturday, 1 May 2010

Lazy, Hazy Dayz

Written 30th

After a fabulous coast drive south,

we stopped in a sunny layby, high above the shore, with a fabulous view out across the Brac and Hvar, and settled in for a bit of fettling and some daisy painting.

And were thus employed until the sun set, in a haze of pink behind the mountain, and Will blew up some of his electronics in some unkown waywhich caused us not to be able to start and stay started...  :(  

For the benefit of those who have more recently climbed aboard the adventure bus, and those who have forgotten the 'project', it being such a long time since any fettling was last done (or we last needed to replace things Will or the engine bay has cooked... ;) here is a short recap.

We are driving a 2 litre petrol, 1978, federal spec bus, imported from Idaho, US of A.  It is fuel injected, one of the earliest ones, and therefore employs space age technology (think about it... Not quite as good as that first sounds!) to manage its fuelling.  Due to the vagaries and variances of US regulations of the time, the injection system it uses is found only on US vans made between 1978-1979 and only those not registered in California...  Makes biying parts expensive and nigh on impossible.

It was originally idling very high, the simple yet surprisingly clever, original fuel map has holes and lumpy bits in it, and generally Will feels we are not as fuel efficient as we should be.   So, the an is for a 'project' to replace/enhance bits of the current ecu in a quest for better fuel consumption and therefore cheaper motoring.

To cut a long story short (the long version is scattered elsewhere in this syory, I can tell you where if you are interested), since being abroad and on the road, amongst other things, Will has replaced the old air-leaky throttle for one out of a modern citroen saxo, and added an airflow sensor from a Ford something-or-other inline with the original airflow sensor.  The new throttle fixed some of the idle problem - we are no longer racing when sat at traffic lights! - but there is still a lot to do.  He has also retro fitted a performance airfilter in the engine bay and a lamda sensor in the exhaust pipe.

The plan, eventually, is to be able to remap the engine so it reads from the new airflow sensor and then tune the map using the lamda sensor for optimum fuel consumption. 

Easy... :)

There are eventual plans for rev counters, temperature gagues and all manner of other fancyness but one project at a time...

The original 'project' which used a ARM processor , bought from home for the purpose, (hammer, nut, springs to mind!) worked for a while but then couldn't hack the operating conditions in the engine bay, and has since been replaced by PICs which Will has written his own programmer, test harness and debugger for.

He is currently at the stage of writing something to control the stepper motor within the saxo throttle, which controls the idle, and was just at a point where it was automatically seeking the right rpm and staying there without too much hunting, when it died.  Obviously it did this midway though a test and left the throttle in such a position as it wouldn't idle.  Brilliant. 

So we settled in for the night, with the brilliant justification for anyone questioning illegal camping, that quite genuinely, our car won't start and we had no choice.  They just don't need to know how it got broken...

But we had no problems of that sort and awoke in the morning to beautiful sunshine.  Fortunately, the ARM chip version of the project still woks sufficiently to reset the stepper motor to a permanent position which enables us to start and idle, but the PIC is definitely dead :(   so we were able to get going and made our way down the hill to beautiful Brela where we spent the day on the beach.

White pebbles, bright sunshine, floating on my back on the surface of  a clear, calm ocean of blue, staring up at another unbroken ocean of blue above me. 


I even went properly swimming, out to beyond where I could touch the bottom!  Twice!!


We even got to watch some proper fishermen at work

But can't stay on one beach for ever and anyway, finished my book, so onwards and southwards once more.  Islands next!

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