[Binji]

As the title says really. Very often when I go to turn it on after it had been left standing over night the revs drop and it almost stalls (sometimes it actually does) for a few seconds. After that everything works as it should.
It used to do it only when very cold (around freezing) but now it does it almost every time. Any ideas?

It does uses up quite a bit of oil if that's of relevance...

 

[smm3008]

Have a look at your battery terminals, they may need tightening. Failing that it could be your MAF sensor.

Sam

 

[kilsby78]

I had that once changed the maf problem solved

 

[Binji]

I was already thinking about changing the earth cable since it seems to take a bit longer to fire up. Might be worth trying...

@kilsby: Did that happen on every start or only when the car had been left for a while?

Any way to confirm it's the MAF?

 

[Giorget2]

You could remove the MAF. It's safe to do so, even though the engine won't run very well without it.

If the symptoms change with no MAF installed, you've likely diagnosed the problem.

 

[kilsby78]

Most mornings it would happen and was sluggish when driving for the first 5 mins until it warmed up , I had a spare maf so replaced and have not had a problem since

 

[Binji]

Ok, thanks, I will try unplugging the MAF before I turn it on. I don't notice any sluggishness but I do drive very tenderly for the first few minutes anyway

 

[Binji]

I tried it today and it worked with no problems at all. I will try it a couple more times but looks like this could be it

 

[Binji]

I went to the car today, unplugged the MAF and when I started it up, it died on me again
Restarted and seemed to be ok for a second, then I heard a click from under the bonnet (probably AC compressor) and revs plummeted down again. I revved it a little bit and after that it was fine. So.. not MAF? :furious:

 

[alfabeat]

Just guessing, but what happens if you turn off the aircon on start up, so the compressor doesn't engage. Could it be that turning on which is causing it to die. Is the idle set too low? How old is the battery?

 

[Pud237]

V6s run very badly without their MAFs plugged in. I don't consider trying the car with an unplugged MAF to be a very good test of anything. The only thing it tests for is that the MAF is dead or not. It won't really tell you much about a MAF that is in poor condition.

Is there anyone you can borrow a MAF from? A known good MAF is a better test.

 

[Binji]

Thanks Pud. It's a pretty rare beast around here so I guess I will have to order a new one to find out.

Battery is about a year and a half old so should still be in good shape. I've been toying with the idea of replacing the earth main strap but I'm thinking these shouldn't really be symptoms of a declining earth?

 

[Pud237]

MAF is shared with some Vauxhall/Opel cars, also 156 2.0 JTS and 2.4 JTD 20v.

 

[Binji]

Just the insert or also the housing? If the insert, do you know what size are the torx screws so I can get it out?

 

[Pud237]

Just the insert, they are either 5 or 6 point security Torx bits, I just use mole grips.

 

[Binji]

Ok thanks. I got a good price so I'll change the whole thing and see what happens.

 

[Binji]

A new MAF is at home and will be going in the car soon.
Still one question though if that doesn't work - how do these cars regulate revs in idle?

 

[sprint_veloce]

Simplistically, the crank sensor measures engine speed, and the throttle position and fuelling are adjusted to achieve the correct idle speed for conditions.

When my cars MAF failed the engine would stall from time to time.

 

[Binji]

Ok thanks. Will report back when I have something

 

[Binji]

Well if my wife's (she takes the car to work in the morning) report is correct then the new MAF has solved it