With no apparent rhyme or reason, when I turn the car on (overnight cold start) it will sometimes do the 3k warm-up procedure and sometimes not. When it doesn't do it, it will run roughly and hold at about 1.5k until engine at is at operating temp and settle to 750 like normal.

What I've noticed is that if I drive the car somewhere and don't get back to it until several (like 6-7) hours later, it will ALWAYS do the 3k start-up. But when starting up in the morning it's a crap shoot whether it'll do it or not.

I always have the clutch depressed, trans in neutral, and foot on brake when I start the car.

Any ideas?

 

Just lately I've been fiddling with the shifter before I start the car and it seems if I hold it a little to the right it will activate the neutral switch and do the 3k start up. I guess it's just a finicky sensor.

 

3k start up is only supposed to occur if the coollant temp is above 60 to 65 degrees. If it doesn't do the 3k start up then it is supposed to idle first at 1.5k as part of the fast idle warm up and it is always supposed to do this unless the mechanism is maladjusted or removed. Starting the car in gear also overrides the 3k start up even if the coolant is above the specified range. Lastly, when the coolant is cold the 3k start up will not occur because it prevents the engine from being reved when the block is cold thus preventing possible engine damage.

 

There is a small temperature switch on the bottom driver side of the rad. It may be intermittant.

 

Ok so the 3k start-up isn't supposed to happen every single time, and when it's colder it will only rev to 1.5k, got it. It's been a little warmer lately, so I think I've been tricked into thinking I've fixed it by fiddling with the shifter. This also explains why it always does the 3k start-up during the day (not over-night cold starts) when it's much warmer. Thanks for the info.

Btw I've been talking about an '86 NA, if it makes a difference.

 

I was speaking from an S4 perspective.