Faster cold starting? Freezing weather!

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Faster cold starting? Freezing weather!

Postby Spiffy » Thu Dec 21, 2017 2:07 pm

Norway is pretty cold in the winter and as it's gotten colder over these past months I've noticed it takes much longer time to crank before it fires(compared to warmer weather).
So I'm thinking it needs more fuel added? But I don't know if I should alter the priming pw or cranking pw setting, where do I start?

Once it catches it runs perfect though. I would just like to try to get it to catch faster...
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Re: Faster cold starting? Freezing weather!

Postby jsmcortina » Thu Dec 21, 2017 2:39 pm

Adjust the cranking PW curve.

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Re: Faster cold starting? Freezing weather!

Postby Spiffy » Thu Dec 21, 2017 2:46 pm

Any suggestions as to how much % I should increase to begin with?
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Re: Faster cold starting? Freezing weather!

Postby elaw » Thu Dec 21, 2017 5:45 pm

More? :lol:

The help says the coldest cranking PW should be 200-400% but I've found my car likes a *lot* more than that:
Capture.PNG
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Keep in mind the temps in that image are degrees F not C. It rarely gets below 0 degrees here but I suspect if it ever got really really cold, I'd need even more fuel than I have programmed now.
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Re: Faster cold starting? Freezing weather!

Postby Spiffy » Fri Dec 22, 2017 8:06 am

I haven't touched the stock settings since it's been starting fine up until now. Gave it 20% more today. Seemed to help, will try a bit more tomorrow

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Re: Faster cold starting? Freezing weather!

Postby elaw » Mon Jan 01, 2018 8:22 am

Hey just to circle back on this, we've had a long stretch of 0-degree (F) overnight temps so I've had good opportunity to tune cold starting. It turns out my car likes even more fuel than the images I posted earlier show! The values in these images for temps < 0 technically haven't been tuned, but the 0-degree values are about the minimum needed to have the engine catch quickly and not stall right afterward:
Capture.PNG
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Capture2.PNG
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I should add I'm also using the "batch fire during cranking" feature. On MS3 (and I think MS2 also?) the injector pulse width is limited to about 65 milliseconds, and a single 65 ms pulse per cycle is not enough to get my engine started in temperatures this cold. The batch fire feature effectively allows injection of 5x as much fuel per cycle on my 5-cylinder engine.
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Re: Faster cold starting? Freezing weather!

Postby DocWalt » Wed Jan 03, 2018 9:58 am

Wow Eric. I've been steadily adding ASE % to prevent the "start then stall short time later" behavior and I was feeling ridiculous at ~75% but I'm apparently not that crazy even with my gigantic cams and such. Today it started and ran until the alternator kicked in then stalled. Clearly not enough fuel yet!
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Re: Faster cold starting? Freezing weather!

Postby 2cvJasu » Mon Jan 08, 2018 2:26 pm

Spiffy wrote:Any suggestions as to how much % I should increase to begin with?

A lot. Very much. What I have experienced, you wouldn't believe how much fuel is needed to start from really cold...

I have 170cc/min injectors on my 602cc flat twin (Citroen Dyane), and I eas really surprised when I started that on about -30C, those injectors had max duty cycle on 1400 RPM and they were practically squirting constant for a while. But very shortly the duty cycle went down when engine was getting a little warmer (not near to its operating temperature before outside temperature went less freezing...
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Re: Faster cold starting? Freezing weather!

Postby goodysgotacuda » Tue Jan 09, 2018 1:42 pm

Are you just adjusting the value, cold starting and testing to see how long it takes to fire reliably?



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Re: Faster cold starting? Freezing weather!

Postby 2cvJasu » Wed Jan 10, 2018 12:51 pm

goodysgotacuda wrote:Are you just adjusting the value, cold starting and testing to see how long it takes to fire reliably?

Yes. Trial and error. And when the temperature is -20'C...-30'C it won't get long to cool down for new testing, especially with small aircooled engine... :roll:
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Re: Faster cold starting? Freezing weather!

Postby DaveEFI » Thu Jan 11, 2018 2:29 am

On early EFI systems, it was common to have an extra cold start injector.
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Re: Faster cold starting? Freezing weather!

Postby 2cvJasu » Thu Jan 11, 2018 2:56 am

DaveEFI wrote:On early EFI systems, it was common to have an extra cold start injector.

Yes, on D-Jetronic, some early L-Jetronic (Citroen Cx 2400 IE for example) and Rover 3.5 with "flapper" (ECU and cold start parts on my table). Must be more, but those I have experienced myself. Those have "thermo-time -relay" to control cold start injection time, and they inject only when starter motor is operated, pretty clever system on those days...
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Re: Faster cold starting? Freezing weather!

Postby DaveEFI » Thu Jan 11, 2018 4:22 am

Yes - my RV8 had the flapper system. When I went MS, I removed the cold start valve and thermotime switch. Cold starting is OK - but then it never gets very cold in London.
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Re: Faster cold starting? Freezing weather!

Postby 2cvJasu » Thu Jan 11, 2018 7:43 am

Reason why I have those parts at my home, is the plan to remove Strombergs from my -76 Range, and install manifold (and all other parts for a while) fron flapper engine. But not now, weahter must get warmer, and also sunlight what we have about five hours...

Also another plan is to replace Lucas ECU with MS2 what I have waiting...
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Re: Faster cold starting? Freezing weather!

Postby DaveEFI » Thu Jan 11, 2018 9:57 am

Unless you already have the flapper bits, best to start out with a hotwire system from a Rangie. Has Hi-Z injectors and a much better quality wiring loom, which you can adapt for MS. Also has a stepper motor idle valve which MS can drive.
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