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[Mr Gav]

I noticed yesterday that when the engine is cold the fast idle is a bit erratic and the lighting on the TID (and dash and centre console lighting when swithed on) dims and brightens with the rise and fall of revs, it`s not a misfire, a bit more like the engine is hunting. It only happens when the engine is cold and runs perfectly apart from this but I can`t understand why the engine problem would affect the lights, if it was a earthing problem or alternator I would expect it all the time.
Time to get a haynes manual 

the car is a 3.0 MV6 manual BTW

TIA

[noel]

may just need to clean your ICV

[hotel21]

Couple of things there I think.

Hunting will be down to the Idle Air Control valve (the ICV) which is on the right side of the engine as you stand and look at it from the front.  There is a guide on here on how to clean this and make it fully servicable.

The brightening of the lamps etc could indicate a failing battery or alternator.  Again, sure there is a guide on howto check and rule out probs.

Good luck!   

[RobG]

As H21 says, "pulsating" lights is either failing regulator in alternator or knackered SAI system (if fitted)

[Mr Gav]

Thanks guys, I did wonder if the pulsating lights were alternator/Regulator related but with the engine hunting at the same time I thought they might be related, especially as it`s only when cold, as soon as the temps come up everything is fine.
I`ll get the volt meter out and see what`s occuring.
Thanks for your input 

[Mr Gav]

Right,the voltage across the terminals when cold fluctuates between 13.6 to 14.25 with the rise and fall of the revs on fast idle, as soon as the temps rise and the idle goes to normal the voltage across the terminals stabilises to 13.7 and the lights stop pulsating.
if this is the signs of the regulator packing up does anyone know where the best place to get a replacement?

[sneakypenguin]

I too would be intereted in this, mine has just started over the last week doing this, perfectly fine when your moving but when you stop the idle hunts (dips to about 350 then back to 500rpm) and the dash lights dim and brighten, I put it down to bad fuel becaue for about two days it was fine then got stuck in traffic and it started again.

[Mr Gav]

Mines ok once it`s past it`s fast idle and I would expect a faulty regulator to affect it all the time not just when the engine is cold.
I`m gonna see if I can get hold of a new regulator and maybe change it next weekend and see what happens.

[Andy H]

Have you read the guide Repairing the Alternator?

There is a spring loaded contact that can corrode and cause low output.


Also have a read of Battery, Charging and Starting Diagnosis

If I read it correctly then between 13.5 & 14.5 volts is the desired voltage, your pulsating lights may just be a side effect of the uneven idle.

I would want to run the full series of tests in the second guide before hoiking the alternator out.

[Mr Gav]

Have you read the guide Repairing the Alternator?

There is a spring loaded contact that can corrode and cause low output.

Thanks Andy, I saw that but thought if i`m gonna take the alternator off i may as well have another regulator to hand.

Also have a read of Battery, Charging and Starting Diagnosis

If I read it correctly then between 13.5 & 14.5 volts is the desired voltage, your pulsating lights may just be a side effect of the uneven idle.

Thats how I read it and I was thinking the same thing

I would want to run the full series of tests in the second guide before hoiking the alternator out.

As I haven`t really had a look at the V6 yet I don`t know if it`s gonna be a 10 minute job or 2 hour job, trouble is I don`t get any time through the week and don`t have a garage and the weather has been crap today so I`ll see how it runs through the week and have a look next weekend.
Thanks for your input 

[Mr Gav]

Well as of Monday morning the problem has cleared off and done a runner all on it`s own and hasn`t returned yet 
Don`t know if it was dodgy fuel, something with the engine or anything else, just hope it doesn`t return.