indigoth wrote:two things
first, I'm not all that impressed with the way your pinz started, Alan. ...
snip....
and so, your crankety-crankety-crank doesn't impress me even tho you only cranked for a relatively short time.
Well I'm not impressed with the slow crankety-crank either. (and commented on it in the video) But the low cranking speed has nothing to do with the EFI, that's the effect of 7 year old batteries and a cold night. Normal cranking rpm is around 250-300, so there was definitely a low voltage issue.
Herbert fusses at me to replace them, but I've realized this is a real world condition. It tests several things for us, most importantly the injector voltage adjustment. Injectors will squirt less fuel at lower voltage, so our controller adjusts for that.
You are right, most pinz's don't have issues with cold starts, the colder the better. Hot starts are normally the more challenging issue. But with EFI it flips a bit, as you have to control:
- * prime- the equivalent of patting the pedal before cranking
* afterstart enrichment- the first 20-30 seconds of full choke before you press it in a bit
* warmup- The slowly decreasing amounts of choke as the engine warms up
* Fast Idle Air- And of course, the choke knob on a carb also controls fast idle air setting, so we have a cranking fast idle, a warmup curve from 1350 rpm down to steadystate idle.
So hot starts are easy, it's coldstarts & driveaways that are more challenging on an EFI pinz. Just more to dial in. Lot's of time.
second, I AM VERY impressed with the cold temp drive-ability of your pinz. I DO wish mine was as drive-able at those "first-thing-in-the-morning" engine temps.
This is what the video was intended to demonstrate. It took quite a bit of work to get all temp drive off capability. And you can do it from cold to hot. Cannot do it well without closed loop fast idle and well tuned enrichment & air setting link to ambient & engine temp. (we key off of both)
my admitedly limited observations ...
Both observations are valid... just one is the effect of a box stock, 134k swiss pinz that has never had a thing done to engine internals. And with old, borderline batteries to boot!
Impacts EFI, but is not the result of EFI. But real world tests are important, and we learn from them. So I keep my borderline batteries for a while. Next cold night I'll top them off on a charger before another cold start and video.
One other note:
Depending on the type of distributorless ignition used, you do see a slight delay before the engine attempts to fire. This is usually one or two full revolutions of the crank. The various cpu's use different methods to index TDC or some other reference point. Ours is a major OEM module, and requires at least one full revolution.
Some will also not fire until they see a set "cranking" rpm.
This is the new norm, I see it even in my new cummins diesel VS my old low tech diesels. That (index TDC) effect contributed a bit to the slow crank/fire in the video, but with proper cranking speed it's not noticeable unless you really know what to look for. The advantages of distributorless ignition and super hot spark are well worth that slight delay.
Have fun, and keep the questions coming!
Alan
