Crawling along in traffic

My question being, is there any disadvantage in doing this, either to wear

No need for that, you are making progress- as far as traffic conditions allow. Saves on fuel, transmission wear and tear and brake pads too, plus providing a more tranquil ride. In very slow moving traffic leave a really good space and while the others ahead of you are speeding up and slowing down, you just keep trickling along at a steady pace. DaveK.

And then a load of bastards cut in and you end up going backwards :(

In heavy traffic on the motorway, I generally stick to the inside lane (especially if a treacle tanker has shed its load :) and, generally, keep up a better overall speed than the double glazing reps in the other lanes . . .

-- Steveski

I'm surprised no-one's suggested this but (unless you've got a very torquey engine) this probably means your idle speed is set a little high, or has become maladjusted somehow recently. Does this occur *before* the engine is fully warrm - ie. in fast idle mode?

You *can* do what you're suggesting with 600-800rpm, but it will take a very light clutch, and more time than you've got, to creep without stalling / judder. You shouldn't be able to do it on an incline either.

My (petrol) Focus will pull away and negotiate the slopes of a local multi-storey car park without touching the accelerator. The idle is where it always has been for the last 5 years - spot on 850rpm.

I have a slightly stiff right ankle that makes really delicate throttle control difficult, and so always use this method of travelling slowly. I'd assumed all modern cars are capable of doing it.

As long as excessive clutch slip is not used, I can't see how it would cause any vehicle damage. It certainly hasn't affected my car in over

70K miles.

Even with older vehicles, it was possible to do this. I used to have a Bedford CA van with sliding doors. My party piece was to let it trickle along in 1st gear, then jump out and walk alongside! (All on private land, of course ;-) )

Chris.

Also sprach "DocDelete" :-

I've found it works on just about every car I've ever owned. Certainly on later cars with fuel injection and cunning ECUs the car just ups the idle a bit if it's about to stall. Diesels, of course, just keep moving anyway.

I used to teach learners to do it and the examiners never complained, except one who grumbled that one of my learners hadn't actually stopped moving at any time during the test except for the formal hill start and other set pieces. He reckoned that it'd have been nice to see 'em do a bit more clutch control in traffic so he could assess it better. I thought that was a bit daft. Then again, he rightly pointed out that the way she drove meant that the brake lights hardly ever came on and that it might be nice to gently press the brake when slowing even if it's not actually doing anything just to show the lights.

On level ground my TD Montego can manage third.

Once again Davidson shows his age, and his choice of cars. I've rarely driven cars with idle-speed control electronics (not talking full blown ECU either) - I dare say the TD Monty has that.

It's got an idle speed valve guv, that applies the throttle for you, diesels have always done it.

Also sprach "DocDelete" :-

Nope. It's got an EGR valve - but even the previous versions with the bog standard Bosch injection did it. Most diesels can.

I'd venture to say all diesels can, I've never seen a diesel pump without an idle speed control device, the natural pump curve would make them all stall or race otherwise.

I've always done this in traffic, and also do it when manouvering to park. Gives you much more control. I've always had large petrol engines or diesels though. Never tried it in a small petrol. It's easier to have one foot on the brake and one foot on the clutch and let the engine take care of itself.

Stuart.

I agree, I wouldn't have thought that it would be good for the car (unless it's torquey).

Also sprach petermcmillan snipped-for-privacy@yahoo.com (Peter):-

Clutch is right up - engine is just ticking over gently with next to no strain. The amount of power needed to keep a car rolling slowly is minimal - it's really only like having a heavy flywhee.

surely any modern ecu will adjust the mix as necessary to maintain about

850rpm. Hence being able to set off without acellerating. As load increases, ecu increases fuel to compensate and maintain rpm.

I do this fairly often at lights, in a 1.2 corsa, so don't talk about torque! ;)

I'll second that on the 1992 model.

Yes, I thought it was a particular feature of diesels.

Daytona

It's normal behaviour for my well serviced '89 1.8l Golf GTi. I've always thought that it was a sign of an effective engine management system; getting good feedback to enable it to match the fuel to the load. Particularly so because my previous '88 2.0l Astra GTE with ~50% more torque couldn't manage it.

You can't in my Golf. Idle is 1000rpm.

I can maintain 1st on an incline and second on the flat.

Daytona

FWIW our Peugeot 406 HDi will trundle along a level road very easily at idle in 3rd gear, and it might just manage it in 4th gear, and it will climb a moderate gradient at idle in 2nd gear.

Best wishes all, Dave - alias TripleS.

Could you give some idea of how many seconds?

I can do that in my car, but the engine is not really happy as it gets back up to 600rpm from 400rpm.

Idling in second gear gives me about 6mph @ 600rpm.

In practice, I would stay in first and use the accelerator until I had maintained 6mph @1200 rpm for (say) 10 seconds, and was sure the queue would allow 6mph for a while; then 'keep some gas' whilst changing, so that the engine doesn't actually fall below 600rpm.

In first our Fabia 1.4 16V will climb our *very* steep drive without use of the accelerator. In second the revs can drop below idle on a moderate slope, it doesn't like it in top even on the level. It has "fly-by-wire" accelerator, I wonder if there is a link to the gearbox.

This anti-stalling facility must make learning to drive easier.

Also sprach "John Pitcock" :-

Yes - and no. It's great for early learners, but don't forget, they've got to get into their own car one day - and it may well be an old banger.