Losing all battery voltage when trying to start car.
 

I recently installed a Harrop SC kit on my car and initially everything was just peachy. Today, however, I had an issue occur when trying to start the car. My keyless entry allowed me to unlock the door, hopped in and the dash lit up as usual but when I pressed the start button everything died. No slow cranking, just a total loss of power in the car. No lights worked, nothing.

The first time it happened I sat there for a few minutes, opened and closed the driver's door once then everything came back to life. The car cranked up and off I went. About 30 min later I was trying to head back to the office from lunch... same deal... just prior to trying to crank the car all the power died. This time various attempts at screwing with the driver's door (no idea why that worked the first time, but hey, try whatever, right?) I popped the hood to confirm the battery terminals were not loose or anything. As soon as I tugged on the positive terminal to see if it was tight I heard the fans kick on. Got in the car, started right up. (The terminal was on tight, btw) Also, I JUST replaced the battery about a week ago so I'm pretty sure that's not the problem.

Unfortunately I don't have my multimeter handy so I can't be sure but I'm suspecting it could be the fused link on the positive terminal. Though it seems strange for the link to fail in such a way that the fuses are still intact.

Can anyone describe how the immobilizer functions? Could the battery terminal have nothing to do with it? If the immobilizer cuts all power to the car then that could explain what I was seeing as well. I'll start carrying my meter around so I can diagnose a bit better if/when it happens again but I wanted to float this thread out there to see if anyone else had run into this in the past.

-Matt

The terminal may not have been as tight as you though. Pull it off, clean the clamp and terminal and put it back on tight. Your description of events is 100% loose or dirty terminal connection. You are overthinking what could be wrong.

I could not rotate the terminal on the battery post at all. Everything is also very clean (like I said, just replaced the battery a week ago and there's no corrosion anywhere). I'll clean the terminal and apply additional dielectric but I have a feeling it's something a bit more. I've had bad battery connections in the past and it was generally very obvious. I barely had to touch this thing to get it to conduct again. And like I said, it wasn't a problem that it just couldn't carry starting current. Everything was completely dead.

-Matt

In addition to cleaning the battery terminals (which sometimes look clean, but a film of varnish can stop the current flow), I suggest you check the battery with a meter.


humfrz

You just have a bad battery. A battery can sometimes hold a surface charge but then when a load is put on it, it fails completely. I see this all the time at work. Don't over-analyze the problem and create a problem that isn't there.

Get the battery tested- and not with a simple volt meter.

The battery is a week old. A weak battery wouldn't be unable to power the clock in the dash one second then crank the car like it's nothing the next. It is an intermittent connection of some kind.
-Matt

That is classic bad connection symptoms. You are trying to find a complex solution for a basic problem. The immobilizer does not cut whole car power. Clean the terminal and put it back on tight and see if you still have issues.

Batteries typically go either within the first week (sounds like an internal connection issue) or after a period of time depending on your area (3-4 years in Florida, more up north). I think you got a dud battery.

Dude read his story closer! Closed the door battery worked. Touched the cable battery worked. He just replaced it and probably did not clean the terminal and clamp well enough is all. Or the clamp wasn't square on the post so although it seems tight it isn't making proper contact. Both those issues are easy to miss when changing a battery and I have done it a dozen times over the decades. Jumping straight to "the battery is no good" without checking the basics first is very poor mechanical troubleshooting. Now, if he cleans and reattaches his posts and clamps and it still is no good then move to the battery, relays, fuses, etc.

I have a question. So recently I installed LED dome, trunk and rear license plate lights on my car and I noticed my car has trouble starting sometimes. And I used to be able to have my car off with the emergency lights on for over an hour and it would start no problem. Now i can't do it for more than 30 min because I'm scared my car wont start. Haha i don't think its the lights I installed but does anyone have any suggestions for what I should do?

Easy solution would be put the lights back to the OEM ones and see what happens. I find it hard to believe that LED lights (which consume less power) would be the cause of the problem. Have you checked your battery fluid levels?

Yeah I highly doubt it's my new lights but I'm going to try that and no I haven't checked my battery fluid level. Is there a cap on the battery for me to check?

Yes, they just pry off.

If necessary, only add distilled or demineralized water and make sure that the plates are covered.

You might check your battery voltage.


humfrz

Thank you! I appreciate all the help :thumbup: