Thread: Low Rev Driving
29th Jun 12, 22:01 #1
Low Rev Driving
Ok I'll try not to beat around the bush for once:
I've got a Silver Vauxhall Astra X Reg (2000). I wanna save fuel so I go round driving at low revs (like 1500-2000rpm). Trouble is, the car has been jolting at low revs recently, and now tonight on the way to Xscape at Milton Keynes the engine light has come on. It stayed on the whole way home too.
This looks like a problem with the ignition coil pack to me - I know that cos I've blown 2 before!
I'm just wondering does anyone know these things, cos I don't know very much... Do you think there is something about the way I'm driving that is causing my coil pack/spark plugs to overheat? Cos I read in the handbook years ago that 2000-2500rpm was recommended, but I do 1500-2000...SPAM - Going off topic to give you the deals you don't want. - (I'll change my avatar back soon)
29th Jun 12, 23:41 #2
I'd see what the code is and maybe get a compression test. A friend of mine that works for BMW claims some cars he deals with have trouble with water in the cylinders because the motors aren't revved enough to cook it off.
30th Jun 12, 11:50 #3
You might have also knackered the DMF (dual mass flywheel) too?
Simply keeping low revs isn't the full story. Especially if the engine is having to inject vast qualities of fuel to keep the engine turning under the load you are putting it.
I've been hypermiling for many months and the best way I've found by far to save fuel is to drive slower.
30th Jun 12, 13:09 #4
- Join Date
- Dec 2007
You can save on fuel by using the BUS,or by buying a car with a better MPG,and smaller engine.My Fiesta 1.8 diesel will do 60MPG even on driving tuition so consider a diesel car.
30th Jun 12, 13:32 #5
Thanks for the responses guys.
I actually save most of my fuel by using my bike for all short journeys - and even for journeys up to 20miles when I travel by myself.
But I do feel that the ignition coil pack has overheated again - the third time this has happened with me in a Vauxhall Astra. The symptoms are the jolting at low revs, especially in low gears, and that's exactly the symptoms I had before. But it always seems to be at high speed on the motorway/dual carriageway that the engine light has come on on the dash - and both times before it was on the M4 that the coil pack melted and broke down altogether...SPAM - Going off topic to give you the deals you don't want. - (I'll change my avatar back soon)
30th Jun 12, 16:10 #6
- Join Date
- Dec 2007
|Get it plugged up to the computor,see what fault codes it comes up with ,other wise you are looking for a needle in a haystack !
30th Jun 12, 19:15 #7
30th Jun 12, 20:03 #8
I think you guys are both right. Sadly I'm disappointed that with the Vauxhall Astra I can drive in 5th gear at 30mph as long as I have good momentum. The trouble is that is the highest gear, so it's the same one you use for 70mph!! Oh what a waste of fuel! Yeah I actually wanted an LPG car.
60mpg - Wow!
Yeah the bus is expensive! But the trains were a shock. Having not used one for years, I found out a single ticket from Reading to Port Talbot is £55, and £110 return. I actually thought it was a WEEKLY ticket!SPAM - Going off topic to give you the deals you don't want. - (I'll change my avatar back soon)
30th Jun 12, 20:04 #9
30th Jun 12, 20:08 #10
I try to save as much fuel as possible on my 35 mile drive to work. I usually get low 70's MPG. But I've been known to get over 80MPG on a good run
30th Jun 12, 20:08 #11
30th Jun 12, 23:03 #12
Thanks guys. Do any of you think that using low revs (not low enough to stall) can cause problems with the coil pack (making it overheat)?
I suspect it may be using too few revs that has done something to them, especially cos two blew in succession in my old Astra, and now this one's going in my recently acquired new Astra (same year X Reg).
Aw I think I might be what is known in F1 as a Car Breaker! What team would want me now...?SPAM - Going off topic to give you the deals you don't want. - (I'll change my avatar back soon)
30th Jun 12, 23:40 #13
i don't think driving at 1500 to 2000rpm is the most fuel efficient - I would have expeted 2500 to 3000 rpm. But more important is to be in the right gear. Sometimes an engine is more efficient revving freely than labouring in too high agear.
This doesn't cure your current engine woes, I suspect an obscure electrical fault possibly even that old perrenial - poor earthimg.Duncan Rollo
The more you learn, the more you realise how little you know.
1st Jul 12, 00:58 #14
Ok I'm gonna try that kind of rev range on my next tank of fuel, especially cos I remember the manual years ago recommending 2500ish. I just assumed that low revs automatically means better fuel economy and engine life... I wanna drive with 2500 instead of 1500rpm and see how many miles I get till the low fuel light comes on. I'm getting about 400miles on a 50Litre full tank atm at 1500, I think that's 36mpg (uk gallons) - not happy with that...
Nice sig btw, I can think of a few people I know who could do with reading that. Come to think of it, I could do with it too.SPAM - Going off topic to give you the deals you don't want. - (I'll change my avatar back soon)
1st Jul 12, 06:37 #15
High revs and lower loads do produce reasonable strain on the ignition system, but not excessive. The lower revs will produce a situation that makes you notice any engine missing though, and that might be what is happening. As revs decrease engine misfires often seem more pronounced than if they happen at higher revs. Some cars will seem like they miss terribly at idle, but once driving you would hardly notice the problem exists.
If you have been burning up that many coil packs it seems to be a bigger issue. These days some of the coil packs even have cooling fins on them, so I'm assuming heat is an issue on many of them.
1st Jul 12, 09:22 #16
For city driving, just under 2000rpm means 58kmh and also gives me the best consumption. If I switch to manual mode 6th gear, the revs and the consumption go down further (to ~1500+ and by ~.5l/100km), but it does seem to struggle a bitHola Amisgüitos
1st Jul 12, 12:14 #17
Thanks Donkey. Everyone's posts are helping me; this is an educational experience.
What did you mean you can get an LPG system for your engine? Can you do that, actually convert a car from petrol to LPG?!!
Wish I had a 6th gear...SPAM - Going off topic to give you the deals you don't want. - (I'll change my avatar back soon)
1st Jul 12, 12:43 #18
1st Jul 12, 13:32 #19
After 10 years I got an Smax 2.0 EcoBoost (turbo direct injection), and hoped to do the same. Turns out Prins have a system for the 1.6 EcoBoost but not yet for the 2.0Hola Amisgüitos
4th Jul 12, 15:18 #20
A year ago I was working in the extreme south end of the city. I live in the extreme north end so I had a cross-city commute every day at just over 70kms round trip.
Taking the bus would take about 75 minutes to commute to work and cost $94.00 for a monthly pass.
Driving my Korean POS took under 30 minutes and averaged $80.00 a month on fuel .“If everything's under control, you're going too slow.” Mario Andretti