Weird cold start up

[Steve8989]

Whenever my car sits for say overnight. When I start it in the morning it's ridiculously loud and rpm goes up to like 1.5k for about 10 seconds then normals out. But is it supposed to be that long and that loud ?
Mods - fbo/e85/no cats.
Only reason I ask, from hearing other fbo mustangs start up they are nowhere near as loud.

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[ice445]

Sounds normal if catless after a cold soak lol

 

[LCK22GT]

Mine is real loud for about ten seconds then starts to tone down. I have it set on quiet start until 9am for the neighbors sake.

 

[Wishbone]

Yeah that's normal. Mine has a Roush exhaust and will rattle the house windows at start up.

 

[mejohn50]

Perfectly normal. What it’s doing is going into a cold start emissions reduction (CSER) ignition timing mode and a targeting a higher cold start RPM. This retards ignition timing and raises the RPM to light the catalysts off quicker to minimize cold start emissions. The later ignition timing can delay the spark event late enough that it may be happening very near or just after the exhaust valve starts to open. This makes for horrible sound without cats.

Since tuners are no longer disabling any of the emissions stuff, this is something you’ll have to deal with. But, to be clear, this is something that can be tweaked in the tuning software if one were so inclined to commit a felony or two.

When comparing to other similar cars, one of two things comes to mind: they either got a tune before the EPA crackdown and they have all that stuff turned off, or the tuners they used didn’t raise the cold start RPM and yours may have. I suppose it’s also possible whatever exhaust system they’re using more effectively muffles those horrible sounds coming from the engine during CSER.

 

[Grimreaper]

Benefit of this for e85 is easier initial starts the colder it gets. E85 lights off easier closer to TDC until some heat is in the chamber. The low or negative timing really helps the first 5-10 seconds on a cold start I'm finding with e85.

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