crappy starting symptoms
 

2000 Z28 A4 73k miles

little background...

alrighty i have a optima red top battery and a 700 watt sound system, have to turn the head lights and fog lights on to turn the car on.

the problem....

when i go to turn the car on 2 days ago it was a real weak start. like the motor was barely turning over, but it finally did. then yesterday i went in to turn it on and it wouldnt even turn on anymore, like the starter wouldnt even make a chattering sound. so i'm thinking hmm weak battery..,. i go and check it with a voltmeter and it says about 12.2v then i go back in the car and try to turn it on again (remember i have to turn the headlights and the fog lights on, its a "kill switch deal") i then turn the key to the on position and then the needles do a full sweep. then i go to try and turn it on. nothing... so i let the battery recharge itself, even hook it up to jump start it...get a full 13.7 volts and try and turn it on again...the lights get real dim and then when i go to it, all the lights go out....then about 2 seconds later they come back on and do a needle sweep.

whats the deal? the headlight/fog light combo putting a big drain on it? It used to work flawless like this (bought it like that already done to it) and she started right up everytime like a champ.

i've checked the connection at the battery and the cables are making contact with the side post and i even took the fuse out of the amplifier to see if that was the cause and still nothing. maybe a starter relay? any and all help GREATLY appriciated in advance. Thanks.

-Alec

check for corrison on the battery cables and as with anything electrical check the ground make sure its not loose. It really sounds like corrision.

:( no no corrosion, just finished checkin on it to make double sure, took them off and cleaned around to be positive, clean connection no loose connections. any other possible culprits?

short the starter see if it turns over easily. If it does then it probably something to do with the headlight security thing, starter solonoid, or something else. lol. Get a volt meter and start looking. just go back from the starter solonoid make sure it gets power after that not really sure where youd go.

**update** had a freind come over and help me out, traced around and came up with a possible suspect. we are thinking that either the battery is loosing its charge over night, or that the load of all the lights (headlights, fog lights, dome lights, amplifier, equalizer, dash lights.) are putting a LARGE (lol yeah i know thats probably the reason) load on the battery, but the thing thats confusing me is that it would start up everytime normally a while back...with all of those accesories lite up. could the battery really have weakend?

Don't the optima batteries come with a 5 year warranty or something? I'd just take mine to autozone and exchange it. What's the battery voltage while cranking?

3 year warrenty, it was already with the car when i bought it so i dont know if they would be able to exchange it, i dont have any of the paper work on it and stuff, would there be a way to be able to prove it to them?

Probably not, if you had bought it yourself you could give them your phone number and they'd just look it up in the computer system.

...crap :(

well what else could it be if it wasnt the battery?

I dont think that much load on any battery could cause that kind of problem. You can get your battery tested for free at NAPA, Autozone, or Walmart.

cool i'll get it tested and see wha happens

i got it to turn on today with the help of some jumpers, been running itaround town to see wha gonna happen, but with out the amp or radio or equlizer hooked up to see if thats a bigload on it. its doing ok....lol and thats the thing thats bugging me so i'll see tommorow i can turn it on to see if it was getting drain over night by something. thanks for all your help so far :burn:

put an ammeter between your ground and the battry and see how much of a draw its taking.

If you are able to start it using jumper cables then most likely there is nothing wrong with the wiring in your car. You need to load test your battery and see if it's any good.

If the battery is good you need to check voltage at the starter when cranking. Lots of times the cable can get corroded inside and you wont even see it. The corrosion increases resistance and creates a massive voltage drop and if you are not getting at least 9.6V at the starter you are going to have a very hard time starting your car.

To check that your "security system" is not interfering you just need to check for voltage at the starter solenoid. With someone cranking the car check for voltage at the solenoid. If you have 12 volts going to the solenoid while cranking then you know it's not your wiring there. It's the smaller purple wire.

Also another good idea would be to see if your alternator is working once you get the car running. Sounds like you are putting quite a strain on your electrical system. You should have the alternator checked to see how many amps it's putting out. Do not assume that because you are getting 14.x volts that it is functioning sufficiently.

alright i'll check that again, like everyone is saying that the batt is more than likeyly the culprit, and possibly the alternator. how do i check the alternator to see if its good? take it off and get autozone to put it on the checking bench? hope its something real simple like the crusty inside of the cables :nod:

I forgot to add that this is if you are infact creating an open in the starting circuit. If you are creating an open in the ignition or fuel area to prevent starting then that is something completely different.

yeah i have to turn on the headlights in order to get juice to the starter, it was done like that when i bought the car and i dont know what wires they sliced into :( so thats why i was wanting a schematic