Rough idle

[NOVA98Cobra]

My cobra is idling like crap, and I need some advice or at least to get feed back on my ideas. Please read this before saying something like its the IAC. I'm not in the same boat as most people (pic related)

So the problem is that the car has been idling rough for weeks, it runs pretty good under throttle though. Today it finally died when i was letting it warm up. Before it just sounded cammed but kept running today it actually stalled out. It has also been eating batteries (luckily my optima is warrantied so I got it replaced twice now). I race wired it my self and I'm no master tech so I could have screwed any number of things up. Because it kills batteries and doesn't die when I have it hooked up to a jumper box my best guess is that the alternator is broken or I have some giant power draw somewhere. the Optima in it that dies today was literally a month old.

Here are some things to consider that make my car a little special:
*race wired ( i yanked everything it didn't need to run)
*smog pump delete (no tune)
*Rear 02 deleted (no tune)
*AC components all gone (no tune)
*Heater core and entire interior gone

It could also be something as simple as plugs because I haven't changed them in ages. Yes I plan on getting tuned but i pulled all that crap before it started idling this bad. The problem just keeps getting worse

 

[NOVA98Cobra]

the only code I'm throwing is a P1414 and considering the Smog pump is gone with no tune that one kinda makes since

 

[stanggirl14]

I'd have your alternator checked, seems like at idle maybe it's not putting out enough for the ignition system. When it died did it start again or was the battery dead?

May not be the problem but electrical stuff can be funny about what it affects.
:rockon:

 

[NOVA98Cobra]

Yea when it finally died the battery was toast. I had to put a jumper box on it to get it going again. Then with the box attached it idled rough it didn't die. Can any old place like adavaved auto test the alternator?

 

[stanggirl14]

Usually they can, advance, autozone, etc. I do believe last time I needed one checked though they couldn't bench test it, I had to have it in the car which doesn't necessarily help you. Something about not having the adapters to mount it on the bench though. Hopefully it's changed but be ready, why the hell they did that is beyond me.

Something tells me your alternator is toast, you can check output voltages with a multimeter at the battery and see what it's putting out while running, should be in the 14v - 16v range I believe, search the forums I believe that's where I found that info.

It may not cure your idle issue but my best guess is that you don't have enough voltage for the coil packs/ignition system so the car isn't getting the spark it needs, at higher rpm it may be putting out enough to eliminate the hesitation/roughness which may be why you aren't having problems then. Hope I'm right tho b/c that's not a hard fix.

 

[NOVA98Cobra]

Thanks that's what I was thinking too so having someone else say that makes me freak out less. Just because I've been yanking so much stuff I assume everything is my fault that's wrong. If its just the alternator that would be great

 

[stanggirl14]

good luck and let me know what you find out

 

[NOVA98Cobra]

Well alternator was good according to advanced auto parts (electrically anyway, the bearing sounded terrible). My optima was dead. I have no idea what could possible kill a brand new optima in only a few hours of run time, if the alternator was not a fault??? So i got one from a friend locally to test anyway because I don't have that much faith in advanced auto. The way my car eats batteries you would think i had a bunch of subs I was always running

 

[stanggirl14]

Well alternator was good according to advanced auto parts (electrically anyway, the bearing sounded terrible). My optima was dead. I have no idea what could possible kill a brand new optima in only a few hours of run time, if the alternator was not a fault??? So i got one from a friend locally to test anyway because I don't have that much faith in advanced auto. The way my car eats batteries you would think i had a bunch of subs I was always running

Man, that's weird. Although I've had bad alternators that tested good at advance auto, changed them and solved the problem. Then again I've replaced one they said was good and it apparently was b/c it solved the problem.

If the bearing sounds that bad I would think it's going, maybe not completely gone but going.

 

[NOVA98Cobra]

Car runs great with a new battery, alternator and ignition switch. I guess the idle was rooted in a voltage problem. Still don't know if I cured the voltage drain though

 

[stanggirl14]

Car runs great with a new battery, alternator and ignition switch. I guess the idle was rooted in a voltage problem. Still don't know if I cured the voltage drain though

Good deal, hopefully it was just your alternator going bad.:banana: