Cranking Pulse Widths ? MS2 vs MS2e

jeffsnyder · Post by **jeffsnyder** » Mon Jan 28, 2008 9:17 pm

From the MS2 Standard code manual

To begin, set the -40°F cranking pulse width to about 88% of your "upper" req_fuel value, and the 170°F cranking pulse width to about 23% of your req_fuel. Those should get you 'in the ball park' for starting

With MS2E the default values start at something like 330% reqfuel for something like -10 degrees. this means the default values for startup are horribly off right ? or am I missing something

What kind of values have you guys been using ?

UnaClocker · Post by **UnaClocker** » Mon Jan 28, 2008 10:07 pm

The values in MS2E ARE percentages. Not actual pulsewidth numbers. It makes it sooo much easier for the normal human mind to understand. So the number you are seeing is a percentage. And unless that number is 330, it's not 330%..

jeffsnyder · Post by **jeffsnyder** » Tue Jan 29, 2008 12:47 pm

Right I know that in MS2e it is a percentage...... from the MS2E manual

"The cranking pulse width is displayed as a percentage of your req_fuel value, at -40°F it should be about 320%"

from the MS2_Standard manual
To begin, set the -40°F cranking pulse width to about 88% of your "upper" req_fuel value, and the 170°F cranking pulse width to about 23% of your req_fuel.

MS2 says 88% of Required fuel
MS2E says 320% or Required fuel

see what im saying....

Post by **muythaibxr** » Tue Jan 29, 2008 1:01 pm

From what I've seen on most of my engines, the cranking pulse-width should be significantly larger than the req_fuel at very low temps..

88% sounds too low to me.

My rx7 requires double the req_fuel on crank at around 30 deg F, so I'd imagine that > 300% would be necessary at -40.

Granted rotaries usually need a pretty good bit of fuel on crank in order to fire up, but not THAT much more than a lot of piston engines.

Ken

UnaClocker · Post by **UnaClocker** » Tue Jan 29, 2008 5:08 pm

Yeah, all of my cold starting issues came down to grossly underestimating how much fuel I needed. I don't have my numbers handy right here, but I recall them being about double what I started with.

hassmaschine · Post by **hassmaschine** » Tue Jan 29, 2008 7:52 pm

mine is at about 300% at -40c - so far I've successfuly started and warmed up the car down to about -10c without problems. it doesn't really get any colder here either so I think I'm pretty well set