V8V high idle speed on startup.

[Healeyguy]

Hi all, I mentioned this issue in some other posts but it probably got lost among all the other stuff being discussed.

When I start my car from cold in the morning it bursts into life immediately but then ticks over at 1500 revs! This carries on for a while gradually decreasing to 1200 and then ultimately to 750. I haven’t actually timed how long this takes but it is annoying because if you set off at 1500 or 1200 the car will shoot forward or you risk burning your clutch to control it.

Is this normal? Do they all have a high tick over when cold starting or does it vary from car to car. Is this an ECU issue? Can anything be done?

If others experience this do you wait until normal idle before setting off, maybe 1 or 2 minutes, or more? I really don’t like the alternative scenario.

Thanks Derek

[matrignano]

Mine was 1200 IIRC but 1500 doesn't sound too far off.
But it did go down to 750 in 10-20 seconds though

[Cold]

Many cars, not just Aston Martin, do this. It's to help the cats warm up quickly.

[john ryan]

Clutch burn is a combination of high slip and high torque throughput, ie high energy. I don't think any serious harm will come from modest slip at high idle if you simply engage the clutch without pressing on the throttle pedal. I think you could slip the clutch for a long time without harm at no load 1500rpm. Bear in mind that high idle revs are probably no more than you would demand if pulling away with a warm engine. Don't worry about it. I'm seven years in and 45K - no hint of clutch slip yet, and I drive positively, but not aggressively.

[bogie]

I thought it was normal in all modern cars, Aston have mapped in the extra little flare on startup. I Just get in it and drive, dont wait for it to settle down at all.

[steveatesh]

Didn’t it used to be called a choke....... I remember the manual choke you had to pull out to start and slowly push it in as the engine warmed.....

My Z4, CLK and Boxster all did/do it......

[NickXX]

Mine does this, and my e46 M3 used to too. I have always assumed that it was normal.

I always start up and pull away rather than waiting - just make low speed driving a little more difficult around carparks.

[bogie]

The cold start routine is more noticeable on the modern Aston due to the flare thats mapped in and the exhaust valve open/close at variable revs giving more noise. On a normal car you dont really notice it sat there are 1200 or 1500rpm because you can barely hear it.

[N7GTX]

Its is normal and is used to meet current emissions regulations. In simple terms the ECU (engine computer) injects more fuel and opens the throttle so causing the slightly high revs. This is done to heat up the catalysts faster as they are inefficient below 300 degrees C. If you watch an MOT emissions test you will see the tester holds the revs around 3,000 rpm to heat up the cats before carrying out the emissions test itself. If you start the engine and drive off immediately, the exhaust gases are hotter as the car is under load and the cats reach their optimum operating temperature much faster. Leaving it idling at 1200-1500 revs before setting off does the same thing i.e. they are both designed to meet emissions regs and to achieve the best fuel economy.

[shinjuku]

N7GTX is correct.

/closethread

[Healeyguy]

/closethread ?

What is that supposed to mean. Is this a forum or isn’t it?

[Healeyguy]

Thanks for the info.

All my previous cars revved at around 1000 on cold startup, but they were all turbo diesels. My wife’s Mini Cooper D does the same.

So 1500 is normal for the Vantage?

John, regarding your comment, re no load at 1500. As the car is stationary the clutch has to overcome the inertia of a 2 ton vehicle at rest. Looks like you have mastered it though and it’s reassuring to hear of your 45k clutch.

I don’t envy people who have to reverse a Vantage out of a garage at 1500 revs!

[john ryan]

It's normal, but it should fall quite quickly. Moving from rest doesn't take much, after all we can push a car quite easily. Slipping the clutch for slow speed manoeuvring will do no harm to the facings; most of the time you will be disengaged once rolling. I do try avoid reversing uphill because of the high ratio which is a feature of this gearbox in similar Ferraris and Lambos.

[Healeyguy]

John, thanks for confirming.