Starting issues

[asshanson]

I'm having a weird starting issue, and the extreme cold is accentuating it. If I let the car warm up a bit to 140 degrees, and turn it off for 4 hours or so to make sure it's completely cold (way below freezing outside), it starts up almost instantly, no problems whatsoever. But if I let it sit for 13 or 14 hours, it takes a lot of effort to start, like 4 or 5 seconds of cranking at least.

Is the engine not really cold after 4 hours in this weather? Why would the extra 10 hours of sitting make a difference? I always let the fuel pump turn on for a second or two to make sure fuel pressure is there. Do the injectors get harder to operate after sitting for longer?

I've noticed this in the warmer weather too, if it sat for a day or two between drives it became a lot harder to start than after 8 hours or so. The issue wasn't as bad though since it was warmer out.

[A//// Guy]

The only thing I can think of is if your fuel pressure regulator is leaking back to the tank, but running the pump should take care of that issue.

Engine usually doesnt get cold cold till atleast 4-5 hours if its 0 out.

Sounds to me like a fuel pressure issue.

[C3L1CA]

Mine does the same thing. I figured it was just part of having cams, e85, 1600s, and no idle motor. Doesn't bother me but if there is a way to fix it, that'd be nice.

[jhaan_dude]

or the fact that the extreme temperature causes frost the build on the spark plugs anything over 4 hours and makes it hard to start!

[asshanson]

Mine does the same thing. I figured it was just part of having cams, e85, 1600s, and no idle motor. Doesn't bother me but if there is a way to fix it, that'd be nice.

Yea, same here. I've just lived with it but would really like to fix it.

I removed my fuel pressure solenoid, I heard that was supposed to help cold starting, but would it help much? I know it just keeps the FPR from seeing vacuum on starting so it has more fuel pressure to start, maybe I'll try unplugging the line to the FPR next time I cold start it just to see if it'll help.

EDIT: Excellent news, you can adjust the cold start fuel adjustments/enrichment in dsmlink v3, outside the global fuel adjustments. In addition to fuel amount, I hope you can adjust a cold start deadtime as well, that would be awesome. Whenever I cold start with my 1600s the short term fuel trim is always around 10% until it warms up, then goes back to around 0%.

[FattyBoomBatty]

Normal cranking speed and everything?

[asshanson]

Yep.

[Shane@DBPerformance]

A cranking fuel table that is coolant temp versus pulse width or whatever would help it start at different temps and then a cold start enrichment table that is coolant temp vs a percent change in overall fueling would help keep it running and you could fine tune it so that your fuel trims wouls stay around zero the entire warmup. You shouldn't need to change the dead time. But it also is fairly normal for 100% stock cars to have fuel trims way out of wack until the car is fully warmed up.