Negative resistance on ground. Didnt know that existed.

[wriscolf]

Hey guys,

So I have isolated many of my issues on my old thread. I tried to bump it but no ones answering. Maybe if i make a new post on my current issue i can get some help.

I recently changed my alternator and battery. Sometimes i am having issues starting. So i did a voltage load test. It failed, 12.7v. I check the alternator for the voltage its cranking out and its about 14v. I tested it by putting positive post on my multimeter on positive side and negative on chassi ground (alternator case itself, Exposed metal on body).

I could be wrong but i think the alternator is good and i am having a bad ground so i did a resistance check on the ground, negative on battery and touching exposed metals like motor, exposed metal on body and other bare metals, and i am getting a negative 4 resistance (-4.xx ohms). I had no idea that resistance could be negative.

Can anyone give me some input? I have absolutely no idea what is going on.

Thanks

[konarider94]

Disconnect the battery and check resistance from just the battery cable to the other places on the chassis. The car battery is overpowering the circuit in your multimeter.

[wriscolf]

Disconnect the battery and check resistance from just the battery cable to the other places on the chassis. The car battery is overpowering the circuit in your multimeter.

Could it be possible that ground isnt my issue and its a bad alternator? I get scared disconnected my battery since i have an RNS-E and i dont have the passcode.

[konarider94]

Could it be possible that ground isnt my issue and its a bad alternator? I get scared disconnected my battery since i have an RNS-E and i dont have the passcode.

Its possible but if you are reading 14 volts at the alternator I doubt it. I was just replying to why you are reading a negative resistance, to get an accurate reading that's what you need to do. If that's your problem or not I'm not sure.

[wriscolf]

Its possible but if you are reading 14 volts at the alternator I doubt it. I was just replying to why you are reading a negative resistance, to get an accurate reading that's what you need to do. If that's your problem or not I'm not sure.

Thank you. I appreciate you taking your time to reply. It does give me an idea. Thanks.

[pezgoon]

You can go on ebay and for like 6$ get the code for it, you just need the serial number on the side or top of it

Also when I had my battery disconnected while doing my instrument panel it didn't ask for a code to unlock it, I think its when its moved vehicles? Although I am not positive

[wriscolf]

You can go on ebay and for like 6$ get the code for it, you just need the serial number on the side or top of it

Also when I had my battery disconnected while doing my instrument panel it didn't ask for a code to unlock it, I think its when its moved vehicles? Although I am not positive

Yeah, i did my alternator and battery before with no issue. I wonder if it has a internal battery and if it drains then it does it.

[Okedokey]

Yeah, any stranage or unexpected results, change internal battery of multimeter.

[Theiceman]

how about backing up and telling us the issue .
if your alt is putting out 14v its fine.

will it just not crank ?

if your battery is in good shape and connections are tight will the starter motor crank ?

[wriscolf]

Yeah, any stranage or unexpected results, change internal battery of multimeter.

I was talking about the RNSE resetting but i think you are on to something. It seems to not be dead but ill see if i change it anyways. Who knows.

how about backing up and telling us the issue .
if your alt is putting out 14v its fine.

will it just not crank ?

if your battery is in good shape and connections are tight will the starter motor crank ?

http://www.audizine.com/forum/showth...ruise-control)

Hey I am sorry, i didnt go to the full story. You can find the whole story in link above. I had a lot of issues. I feel i am coming down the stretch into fixing the issues.

Now to answer your questions,

If i test the alternator itself from positive post the the negative body of the alternator, It reads at 14v (with load on cant really check without a load since i have no idea how to turn off radio fully and such). If i check from the battery it fails. with a 12.9v or something i forget the number from the top of my head. Seeing that theres two different outputs one from the alternator and battery i suspect ground. So i did a resistance test. Thats when the negative resistance comes up.

My car starts every day and i drive to work and i can do errands and everything. Problems is in the morning, It doesnt crank/start up as easy as if i do errands (car is hot), Especially if i leave something plugged into the lighter. It takes a bit longer to start up (more cranks on same turn of the key).

At this point i am suspecting a bad regulator. Maybe the alternator has the power but the regulator isnt regulating right? Idk, Audi's are complicated. Kinda miss my Nissan Sentra SE-R Spec V but i do love my B7 more than it. I just dont like having issues with my cars since i do long drives and im very dependant on my car for mobility.

[Theiceman]

okay sounds to me like you are waaaaaaay off.

if your car cranks fine but just doesnt fire up as quickly cold sounds like you are losing fuel prime overnight or cold enrichment isn't working as it could.

if in the morning it turns over very sluggishly but fine after that you have a parasitic drain that is draining your battery so you need to look for a current drain when everything is turned off.

[wriscolf]

okay sounds to me like you are waaaaaaay off.

if your car cranks fine but just doesnt fire up as quickly cold sounds like you are losing fuel prime overnight or cold enrichment isn't working as it could.

It sounds like this one. But its really a mixture of both. I make sure nothing stays on besides the "walk me home" thing or whatever but that shuts off. I dont think anything else stays on.

I was thinking that fuel too. Maybe the LPFP or fuel filter. It only happens when car sits for a while. More than 8 hours and in the mornings. I drove to work today. I am confident i can go start the car up. I wonder if its both. I do think the battery isnt getting enough charge since the voltage test at battery is not as high as it should be. It seems to lose power. I am doing a waranty exchange on alternator with pepboys soon when i get a chance. Been ultra busy as of late.