High Idle with Headlights On

[Bigrig]

Howdy

Another quick one hopefully - whenever I turn the headlights on (normal beam) the engine idles up about 250-300 rpm. If I pull up to a set of lights as an example, I can feel it lurching - drop it into neutral and it heads straight up to 900 plus rpm - turn the headlights off and sure enough, every time it just lowers immediately back to 650 rpm.

Understand that accessories use power and in turn they can cause it to idle up a little, but this has only started a month or so ago, and is a huge rpm jump.

Thoughts and opinions??

Thanks in advance as always!!!!

[the ferret]

does it still idle up when you turn the air con on?

[Sir Roofy]

Maybe your running a bit to much wattage or the alternator might be fatigued

[Bigrig]

Thanks lads - air con kicks it up about 50-75 rpm at full tilt (on high) with lights off. Alternator is only 5 months old and was a new 110 amp Hitachi (bigger than stock unit). Not sure what you mean by running too much wattage mate?? Have Narva driving lights and they were put in about the same time as the alternator.

[Sir Roofy]

Thuoght the globes might have been drawing more power than the alternator could keep up with

[the ferret]

MMMM, the draw from the lights is sending a message somewhere, and this is causing another message to go to the hi idle unit me thinks.

[Bigrig]

MMMM, the draw from the lights is sending a message somewhere, and this is causing another message to go to the hi idle unit me thinks.

All very confusing to me mate!! lol

Just becoming somewhat of an issue - the lurching at lights is reasonably prominent due to the engine wanting to take off being idled up - if I let the foot off the brake in idle, I'd easily climb a hill without touching the accelerator!!! Hmmmm, is that a good thing? I think not!!

[growler2058]

Howdy

Another quick one hopefully - whenever I turn the headlights on (normal beam) the engine idles up about 250-300 rpm. If I pull up to a set of lights as an example, I can feel it lurching - drop it into neutral and it heads straight up to 900 plus rpm - turn the headlights off and sure enough, every time it just lowers immediately back to 650 rpm.

Understand that accessories use power and in turn they can cause it to idle up a little, but this has only started a month or so ago, and is a huge rpm jump.

Thoughts and opinions??

Thanks in advance as always!!!!

Maaate See the lil pedal on the right...... take ur foot off it haahhahahahahahahahahahahah (Vino Night)

[the ferret]

I spose it wouldn't hurt to check all your earths, a bad earth can some times cause all sorts of magical events, mine was a bad earth and when I turned the headlights on, the horn would blow, work that one out!!

[Sir Roofy]

Just out of curiosity disconnect a set of driving lights and see what happens
if the revs drop theres a starting point