Sudden Loss of Engine (electrical) Power; Everything Else Working

PassGasNRun

Junior Member
Joined
May 6, 2023
Posts
3
Reaction score
0
Location
NC
I'll put as many details as I can think of:
I'm not a mechanic, but not a novice DIY by any stretch.

05 GT Automatic
Drove it home from work.
Cooled down for an hour.
Drove it onto ramps to swap out O2 sensors. TURNED OFF ENGINE to prevent the exhaust from getting hot.
Didn't like the position on the ramps. Went to turn it on and back off...
... The engine cranked like it always does, fast/strong, but this time no ignition. Not one cylinder getting spark from the sounds of it.
I can hear the fuel pump working.
It didn't ever quit with a sputter. No "choking out" symptoms. It just wouldn't start.
I popped the hood, started pushing down on the relays and fuses (box over the passenger wheel well). Was thinking a relay or such could be loose/dead.
Had to crank it a couple times for a few seconds each, but then VROOM, it was back to normal... for about 20 seconds.
Then, dead. Total engine electric failure. Everything else electrical seems to be functional.
Crank crank crank... VROOM! STARTS AGAIN! Idled for 30 seconds, quit... 5 seconds... quit... a minute... quit... 10 seconds... quit... you get the picture.
When it runs, it runs PERFECT... aaaaand then it quits. UNLESS....
I started it and kept my foot on the gas. Just a little north of idling, it TRIED to quit. One little (total engine) skip and then back to purring. This would replicate.
So I rolled the dice and went for a short drive.
At slow speeds (Low RPM) I could feel it try to die, but it would just skip hard and then keep on going.
At higher speeds and acceleration, I couldn't notice it.

My thoughts:
If this was an old school, I'd swap out the coil cable, then the coil, then the ECM for the distributor, then the distributor.
Is there a relay that could be going bad?
Could it be something in the key/ignition/switch/harness?
I SERIOUSLY doubt there's a fuel delivery issue of any sort.
Any help is appreciated.
 

PassGasNRun

Junior Member
Joined
May 6, 2023
Posts
3
Reaction score
0
Location
NC
Sup PassGasnRun here's what I'm thinking. Bad ground. From battery or to the chassis.
Thanks. Already checked that. Clean terminals. Solid connections. Like I said, ALL OTHER ELECTRICAL parts function normally, even during the engine electrical (temporary) death.
 

VBSTANG06

Junior Member
Joined
Feb 29, 2024
Posts
40
Reaction score
4
Location
North Carolina
Engine seems to not be the problem. What's battery voltage at idle/partial throttle? It dies quick for no reason so, if you want, hook up scanner w/key to run position and get live data going so you can kind of see how it's behaving then start it up and check battery voltage
 

john knox

Junior Member
Joined
Sep 7, 2020
Posts
13
Reaction score
6
get forscan.org software, it kinda sounds like ecu or power wire going to it or the grounds going to ecu,
 

Latest posts

Support us!

Support Us - Become A Supporting Member Today!

Click Here For Details

Sponsor Links

Banner image
Back
Top