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· Pumps 1 and 2, hit 'em!
1,283 Posts
Discussion Starter · #1 · (Edited)
I'm struggling being an automotive novice tracking down an open circuit or electrical problem on my Supra.

The problem:

Last night, 4/28, I start the car normally under its own power, idled it for 2 min, turned the HIDs on, started backing out slowly from the garage. About 30 seconds later when I'm trying to find my garage clicker, the HIDs shut off completely, dash lights started flickering bad, car almost stalled, but I managed to limp it right back into the garage.

The battery was replaced and verified to be fully charged. Yet the car can barely start under its own power or illuminate the dash lights.

Turning the key to position 2 without kicking the starter over, the dash lights flicker for 2 seconds and the door chime stammers for a second and then all lights come on fully like normal. Like there's some sort of open circuit leeching power.

The battery with the car off, alarm off, registers no draw at 13.0x to 13.1x volts.
Measured at the battery with the car idling poorly in this half ass running state, shows 14.2x to 14.4x volts.

When I turn the car on in this state, it struggles to turn over like the battery is dead, and when it does turn over, all my dash lights go out completely except for my warning triangle, ABS light, and seat belt light. These are flickering at only partial juice.

The car idles terrible, the Zeitronix shows O2 voltage, vacuum, EGT, and AFR are all ok. The Vipec V88 is on and working, connected to my laptop I verify it's operating and my tune was not lost. I don't even get the tac to register unless I rev it to 3,500-4K RPM and it bounces around the 2K-2,500 RPM range.

The overhead light won't even come on, no A/C panel lights, the windows won't work. Juice is not flowing, come on Scotty!

If I pull the negative terminal OFF the battery, the car struggles to idle but it idles and wants to die unless I feed it around 500rpm. This tells me the alternator is providing current but why isn't it reaching the places it needs to get to, particularly when the battery is connected to provide a boost?

Is this a regulation problem inside the alternator?
Is this a grounding issue?
This doesn't seem like a vampire/constant draw but more like a short or open circuit?

How do I go about checking these things and in what order? I can change my own fluids and that's about the extent of my experience with autos. My car is dropped just over 1" and I don't have a jack to check grounds that might be under the motor or under the car.

I'm out in BFE Ventura County so going to a shop I trust will require a tow and taking a day off work if I can't pinpoint the issue by checking grounds with some forum assistance.


I have a Promax HID kit, some no-name brand battery, a Blitz Turbo Timer, Vipec V88 stand alone, Zeitronix remote LCD display, and an aftermarket alarm.

I left the HIDs on twice in a week time frame which killed the battery.

4/18 I drove to work and left the lights on. Had to get a jump start from AAA, alternator and battery were fine. Drove home no problem, parked the car. Drove it 75 miles a day for the next 3 days. Zero electrical issues, to my knowledge.

On the Friday 4/22, I washed the car after getting back from work. Started the car up, parked in the car port space instead of my garage, and I left the damn lights on again. Zero electrical issues, to my knowledge.

On Sat 4/23 the car barely started under its own power, idled terrible, dash lights protesting due to running on just alternator. I limped it 500ft and parked it in the garage, stuck the battery on a tender, and left it that way to charge.

On 4/26 I was able to start the car normally, idled it for 10min, shut it off. This is with a new battery.

Left it on the tender 2 more days. It's a 1.5A computer controlled charger/maintainer for cars/motorcycles.

· Pumps 1 and 2, hit 'em!
1,283 Posts
Discussion Starter · #2 · (Edited)
Next thing on my list is checking fuse and with key in pre-start position 2 checking which systems work and don't.

I have not done this yet after being flummoxed and working from home today. I feel dumb for not checking this first, but I'm not a mechanic! My excuse and sticking to it.

So far Kal has been helping me over chat. Any other sage words of advice, other than don't disconnect the neg terminal and spike the crap out of my systems, are appreciated.

· Registered
1,475 Posts
thats sound like a bad ground

· Pumps 1 and 2, hit 'em!
1,283 Posts
Discussion Starter · #4 ·
Update: The negative battery terminal bolt was stripped at the base two threads allowing the nut and end of the terminal to spring loose, but feel tight. However, this was half the story. The negative terminal itself when fully tightened down, might feel very tight, but any upward pressure or movement will cause it to loosen and it can be spun/pulled right off. I'll be towing it close by to have a new terminal or cable + terminal fitted.

When I did get it cinched down as tight as I could by compressing the middle section and fitting it on the battery, it fired up on the very first crank and immediately settled into a smooth idle and I had no flickering issues or power problems until the vibration from the motor caused the terminal to start to loosen up.
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