paalw

At least thats what the instructions manual says. You should drive off right away, not let the engine idle after cold start.

Just curious, is there any technical explanation for this or did they just consider the environment back in 1986??

Mongo

Probably 1 thing I don't follow in the manual as I let my car warm up for a minute or 2.

blitz928

Because the engine will be warmed up, but the transmission will not be up to temp. This goes for all cars.

andy-gts

matt what is your answer to?

Imo000

Fuel injected engiens warm up much faster if they are driven and so is the catalytic. All they need is 30 sec. of idle to bring the oil pressrue up to normal and then you are good to go. This goes for all FI car since the mid 80's. This doesn't mean you go pedal to the metal as you and you get moving.

76FJ55

Apparently it's not just for FI cars, as my 1976 Toyota Landcruiser has a similar statement in its maunal.

jeff spahn

You mean I shouldn't floor it and make the cool sounds as soon as I start the car?

Lizard928

I always get in and just drive my car. Except for in the winter, and then I let it idle for a few minutes. This is mainly while I scrape the frost off the windows!

hacker-pschorr

Has nothing to do with fuel injection, good poing on the CAT.

You can idle a car for a very long time (especially in the winter) without the oil going up much in temperature. You want the oil to reach full operating temp as fast as possible. This is never going to happen at idle. The 928 makes things worse by having a 9-10 quart sump.

Revving it in neutral doesn't help either, needs to be under a load. The longest I've ever let my Audi idle in the winter was just over 10 minutes, the oil temperature gauge didn't move at all (yes I know it's accurate). My coolant was warmed up, that doesn't mean anything for the oil.

This is why you should not start up a stored car unless you plan on driving it.

the flyin' scotsman

Interesting comments.

The 928 auto transmission spins when the engine is idling and the trans. is in park or neutral and the trans oil heats up. This is one reason the trans oil level must be checked with the engine running per the WSM.

Any vehicle parked outside in our winters require time to warm before moving................metal gears etc become very brittle at extreme low temps.

My 928 is tucked in the garage for the next 3-4 months so no worries.

Tom in Austin

Isn't the issue that the ECU runs the engine very rich at start-up, and the sooner it can lean out the less raw fuel dilutes the oil in the cylinder bores and ends up in the cats?

I've always understood the idea is to avoid loading the mechanicals while they're cold. If you pull away gradually with a cold drivetrain that doesn't stress things any more than idling.

Mike Frye

My oil pressure shows full (5 bar) immediately on startup, but it's still really cold and usually takes about 5 minutes or more of light cruise (under 3k rpms) before it's thinned out to normal viscosity where it will drop to 3 bar at idle and go up to 5 bar at 2k+.

I think the start up map only lasts until the O2 sensor warms up though, no?

I agree about taking it easy at startup, with the 5 speed shifting can be a little notchy when it's REALLY cold out. That's when I broke my shift centering spring too. I guess it was cold and brittle and when I pulled the shifter over for first, there was tension and then NONE. I think one benefit of having the exhaust go right near the trans is it helps warm up the trans fluid quicker on really cold days.

Lizard928

Especially with the oil cooler in the rad.

Calgary Ole

I warm my truck at least 15 min every morning in winter up here, but as you say, the tranny is still frozen up until I get a few miles down the road.

Lizard928

Ole,

When I was in really cold areas, I would put a 500W halogon lamp on the tranny. This made it a little more liveable.