High Idle with Headlights On

[Finly Owner]

Bloody hell are you reading the solutions to the real problem? You seem to be missing them? I agree enought that, you need to check how much actual draw you are pulling from alternator:

Watts/ driving light
Watts/ headlight
Watts/ in all your Leds
Watts in fridge etc
Air con running?

Deeduct from 110watts supplied, and how much for charging batteries and power to keep motor running is left?

Tim

[YNOT]

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!!!!

You've got me scratching my head trying to explain this one!

The problem only started about a month ago, does that time frame coincide with any work on the car or any trips-particularly muddy trips?
Does it make any difference switching between low and high beam and also spotlights on and off?
Does the idle drop back to normal as soon as the headlights are switched off?

Tony

[Bigrig]

You've got me scratching my head trying to explain this one!

The problem only started about a month ago, does that time frame coincide with any work on the car or any trips-particularly muddy trips?
Does it make any difference switching between low and high beam and also spotlights on and off?
Does the idle drop back to normal as soon as the headlights are switched off?

Tony

Have to say mate, I'm glad it's not something really simple that I overlooked!!

Doesn't coincide with any work that I can pinpoint. Doesn't coincide with any trips. I believe it makes no difference if high beam is on (happened on way to Sydney last time on a night run, and used high beam and spotties a lot). Turning spotties off and on does zilch as far as I'm aware, but haven't actually tested this one. Drops back to normal each and every time I turn the headlights off (have even found myself doing this at traffic lights at night etc, just to get it to kick back).

Confusing? And you're smart!! Imagine how I feel!!! LOL

[Finly Owner]

What volts are being produced? I assume you have voltmeter working? Are you running HID bulds or just high watt bulbs? If you have increased bulb watt size, did you run them through extra relay? Is it still earthing correctly?

[Sir Roofy]

have to say mate, i'm glad it's not something really simple that i overlooked!!

Doesn't coincide with any work that i can pinpoint. Doesn't coincide with any trips. I believe it makes no difference if high beam is on (happened on way to sydney last time on a night run, and used high beam and spotties a lot). Turning spotties off and on does zilch as far as i'm aware, but haven't actually tested this one. Drops back to normal each and every time i turn the headlights off (have even found myself doing this at traffic lights at night etc, just to get it to kick back).

Confusing? And you're smart!! Imagine how i feel!!! Lol

night run high beam and spotties on bet its a crook soliniode ,RELAYits ok when cold but plays up when hot

[YNOT]

Have to say mate, I'm glad it's not something really simple that I overlooked!!

Doesn't coincide with any work that I can pinpoint. Doesn't coincide with any trips. I believe it makes no difference if high beam is on (happened on way to Sydney last time on a night run, and used high beam and spotties a lot). Turning spotties off and on does zilch as far as I'm aware, but haven't actually tested this one. Drops back to normal each and every time I turn the headlights off (have even found myself doing this at traffic lights at night etc, just to get it to kick back).

Confusing? And you're smart!! Imagine how I feel!!! LOL

The fact that the fault occurs on low beam would to me eliminate the high power drawer theory (ie, too many accessories overloading the alternator).

There are 2 seperate valves that control the idle, both are mounted on the back of the inlet manifold phlenum chamber. One is the FICD (fast idle control device) which is only there to compensate for the air conditioner loads, this appears to be working normally.
The other valve is the AAC (accessory air control) valve which compensates for all other loads, something is corrupting how this valve operates. It could be something as simple as a bad earth.

Tony

[Bigrig]

The fact that the fault occurs on low beam would to me eliminate the high power drawer theory (ie, too many accessories overloading the alternator).

There are 2 seperate valves that control the idle, both are mounted on the back of the inlet manifold phlenum chamber. One is the FICD (fast idle control device) which is only there to compensate for the air conditioner loads, this appears to be working normally.
The other valve is the AAC (accessory air control) valve which compensates for all other loads, something is corrupting how this valve operates. It could be something as simple as a bad earth.

Tony

Righto - thanks. Funny thing is, the NDS software monitors the FICD and the AAC sensors, and nothing is showing up for either with lights on ...

Bad earth? Wouldn't I have flickering lights at least (on occasion) or something physical/tangible to see for a bad earth issue??

Sorry, not flash with auto electrics .. or mechanics ... or much else ... LOL!!!

[growler2058]

Righto - thanks. Funny thing is, the NDS software monitors the FICD and the AAC sensors, and nothing is showing up for either with lights on ...

Bad earth? Wouldn't I have flickering lights at least (on occasion) or something physical/tangible to see for a bad earth issue??

Sorry, not flash with auto electrics .. or mechanics ... or much else ... LOL!!!

Pretty good with your acronyms tho I have NFI for your RFI hahahahahaha

[YNOT]

Righto - thanks. Funny thing is, the NDS software monitors the FICD and the AAC sensors, and nothing is showing up for either with lights on ...

Bad earth? Wouldn't I have flickering lights at least (on occasion) or something physical/tangible to see for a bad earth issue??
Sorry, not flash with auto electrics .. or mechanics ... or much else ... LOL!!!

Not necessarily.

Tony

[Bigrig]

Not necessarily.

Tony

Then I'm stumped - take it to an auto sparky??