Car won't idle when the lights are on?

[kissrocksforever]

I did a search and didnt find anything about this even on google.

My car is a 94 GT 5 speed, with H/C/I with full bolt ons, no tune on it. It has a bit of a surge but nothing bad, most of the time it doesnt surge at all actually, it will just dip down 150 rpm then go back to where it was and continue to idle fine...Until I turn on the lights, which is when it starts surging a good 500 rpm and dies withing 10 seconds. If I turn the lights off before it dies, the idle smooths right out. None of the other accessories like my radio or AC cause this.

What is this I don't even?

any ideas?

 

[JoshHooten]

Def sounds like an alternator prob. Maybe the voltage regulator is bad.

 

[Marvin97]

does the car have underdrives? could be a charging issue like JoshHooten said as well. As far as the idle, i'd check for vacuum leaks. Could be a combination of a few things causing the car to surge/die

 

[JoshHooten]

+1 on the underdrives.

 

[JerZeyStangz]

With a IAC potentially to be bad compounded over a weak alternator, and wallah you got a semi-serious issue. My car surges every once in a blue moon because it still has its orginal IAC, and I've been lazy on cleaning it. When I do h/c/i I'll get a new one, but yeah a worn out IAC with a weak alternator or a component of the alternator being bad can cause problems. Make sure your battery isn't a culprit either.

 

[toyman]

Check the battery to engine and engine to chassis grounds. Extremely important for the sensors to function properly. Look for corrosion in the cable by stripping back the sheathing for about 1" from the terminals. If there is corrosion replace the cable.

 

[FrankenStang]

surges and dying when the lights are on would sound like a voltage regulator to me..

 

[greenscobie86]

+1 on Voltage reg. Had that problem on my 96 Cobra once.

 

[kissrocksforever]

Yes the car has underdrives.

 

[Marvin97]

Yes the car has underdrives.

I would find a stock alternator pulley first then, replace it and see if you're still having issues.

 

[dirtyred11]

Man I'm so glad I can tell u wat it is, Der is a ground wire that connects 2 the negative side of the battery and the frame. That's the prblm, I had the exact same prblm after I took that wire off thinking it was 4 nothing and my car did the exact same thing. I gurante it

 

[rz5.0]

also check the ground coming of the the harness for your headlights.. there should be one each side