'Car electronics slowly died up on-ramp' - theories?

Post by **smacknab** » 16 Oct 2021, 10:22

Hi friends,

Just got back from a trip away and my wife drives the S70 as her daily. She said yesterday when she was going up an on-ramp' the electrical systems in the car slowly died out. She stopped the car restarted it and it went fine for the rest of the drive home. I'll have to scan it when shes home but i wanted to see if anyone has some easy answers for what could've caused this?

The battery is about 2 years old but a cheapish AutoZone battery iirc. The current alternator is a tested junkyard unit that i put in about 2 years ago also. The car hasn't given me any electrical issues in the 2 years I've owned it.

My obvious answers would be the battery, the alternator or a bad ground. The fact that she cut the engine and restarted it makes me think the battery is fine or at least had enough juice to activate the starter. Also, about 2 years ago the AC compressor seized so i drove it home with a smaller serp belt that ran the alternator clutch backwards (99's have a 1 way alternator so essentially it was just driven off the battery power) so that would make me think the alternator wouldn't have such a sudden impact... So this makes me worried that something like this could be caused by the ECM?

Any tips of where to start?

Thank you!
Sean

Post by **volvolugnut** » 16 Oct 2021, 11:06

If the On ramp was a slope up with acceleration, perhaps a wire leaned back and shorted the electronics?
Returning to level, the short opened and everything was fine again.
Test with heavy acceleration up hill. At least that will be fun.
volvolugnut

Post by **scot850** » 16 Oct 2021, 11:11

Is the battery hold down in place? Make sure it is so the battery is not moving.

Don't think it is the ECM. You usually get warning of this with random engine issues like limp mode.

Your wife is not one of those folks who likes to have a whole bunch of keys or other stuff hanging from the key ring? I am thinking this is more likely an ignition key issue.

Neil.

Post by **abscate** » 16 Oct 2021, 11:52

You probably aren’t getting a good description of what happened. Definitely start with evaluation of the battery rest voltage, cables, alternator.

Also inspect fir rodent damage

Post by **smacknab** » 16 Oct 2021, 13:56

abscate wrote: ↑16 Oct 2021, 11:52 You probably aren’t getting a good description of what happened. Definitely start with evaluation of the battery rest voltage, cables, alternator.

Also inspect fir rodent damage

Yeah this is actually correct. I talked to her more about it and she said the lights and the radio were fine the engine just slowly died. Maybe the throttle body or acceleration pedal sensor

Post by **scot850** » 16 Oct 2021, 14:42

How about something simpler like fuel pump relay. How full is the fuel tank? Maybe the tank is low or the pump is losing suction pressure?

Neil.

Post by **abscate** » 16 Oct 2021, 15:05

Sounds a bit like limp mode on a 99 but that usually triggers the ETS light

Post by **scot850** » 16 Oct 2021, 15:46

Like abscate says, that is why I don't think it is the ETS/ETM. Anything is possible but not convinced this is the culprit, yet!

Neil.

Post by **BEJinFbk** » 16 Oct 2021, 18:42

Suspecting some aspect of engine management,
have you scanned for any stored trouble codes?

Post by **rguzz** » 19 Oct 2021, 20:50

I'll cast another vote for a fuel related problem. Maybe check pressure at the fuel rail before chasing too many other possibilities.