probably a dumb question about high revs at start-up

Is it actually revving or the needle just bounces to max and back?

edit: Kinda makes sense why Range is always ranked so poorly on reliability if they are automatically revving a cold engine haha

 

It's done for emissions purposes, getting things up to temperature and such (like getting the catalyst "fired up" to handle those raw hydrocarbons), and with today's thin multi-viscosity oils I'm sure there is no concern for the motor even in winter. In older cars with fast-idle settings I personally don't like how it feels but likewise think there is no harm done. You'll probably end up using your right foot to keep it running and warming up if the car didn't do it itself.

 

I don’t know of a single car that will actually rev to redline when started up. The rev counter might go all the way but not the engine itself.

 

They definitely rev 2,000 to 3k but if a car actually revs to redline that's news to me. They always idle a bit higher too until warmed up but that's common knowledge.

 

The needle sweep is just for show, the high idle is strictly for emissions and getting the cat up to temp faster, it's usually dumping fuel in at the same time. You can turn all that nonsense off with a tune if you've gone the catless route. I always turn the cold start high idle off on my cars once the exhaust is done, it keeps the neighbors happy early in the morning and saves a little bit of gas.

 

At one point the 308s were set up to run at something like 2500-3000 rpm when cold to meet emissions standards . The engines didn't last as long. I recall reading that it was easy to disable that fast idle mechanism.

 

yes - the 308's especially the early Injected cars would catch and go up to about 3K,, then come down to 2K and eventually bounce down to 1500 rpm and then hunt for idle around 900 -1K... basically you dont even want to try to drive the car when its in fast idle... the check valve and relays would go crazy... and the car would jerk when accelerating until it got about 150F... ( thermotime switch started to lower idle. I think most guys just disconnected the o2 sensor and then connected it up for passing emissions.

 

I have here a 308 GTSi road test from the March 1981 Road & Track. The writer says that "one can't help but cringe" at the "2500-rpm cold idle".

 

No stock ICE engine is programmed to hit redline at startup. That would be terrible for a cold engine especially a performance engine with solid lifters.