Engines revs up briefly when starting (1 Viewer)

[4Ruster]

2lt, mech pump.

As it's getting colder out I'm noticing when I crank the engine over, as soon as it catches it revs up for a second then drops down to itd normal idle. Like if you blipped the throttle accidentally. This is the first time I've seen this, doesn't happen all the time, only if it's been sitting overnight or after work.

 

[GTSSportCoupe]

2lt, mech pump.

As it's getting colder out I'm noticing when I crank the engine over, as soon as it catches it revs up for a second then drops down to itd normal idle. Like if you blipped the throttle accidentally. This is the first time I've seen this, doesn't happen all the time, only if it's been sitting overnight or after work.

Normally the ACSD system does something like that (but longer) I think? Yours is removed tho?

I can't say why that is happening, but it seems like a handy thing for cold starts in any case, haha.

 

[4Ruster]

Yeah my ACSD is gone.

I'm not too worried about it, just curious is anyone else has this happen. It just started after taking the top of the pump off in my last weekends project.

I know when the VE pump is started, it runs in the full fuel setting for ease of starting, maybe there's just some resistance in the throttle pivot causing it to delay a bit.

The 12 valve Cummins all do this too I think, wonder why mine decided to switch into Cummins mode all of a sudden