97 850 dash/headlights flickering only at startup. UPDATED

Peevarino · Post by **Peevarino** » 26 Dec 2019, 12:01

Dash illumination and headlights flickering only after startup at idle. Giving it gas while idling cures it temporarily, but the issue never arises once I’ve been driving for a bit. Car is a little slow to turn over, but never fails to start. Battery is less than a year old, and battery cables and terminals are mostly free of corrosion.

After driving to work, tested voltage this morning at the battery terminals and at alternator with engine still running, results were higher than expected, over 16 at battery and over 17 at the alternator and was still over 15 at the battery after sitting for 3 hours.

The multimeter’s battery is suspect, it read a fresh 9v at 9.6v, so I replaced it and will re-check battery later and alt and battery when I get home.

If the numbers are close to the high numbers earlier, is this the voltage regulator messing up? Or could it be something else causing the alternator to overcharge?

ETA With refreshed multimeter battery was at 12.5v, 7hrs after shutting down. Will still retest when hot after I get home.

UPDATE after getting home, 13.8 at the battery, 14.2 at alternator.

Post by **abscate** » 27 Dec 2019, 05:31

Battery is less than a year old, and battery cables and terminals are mostly free of corrosion.

Get the squeaky clean and shiny. The corrosion can be under the insulation where you can’t see it. An IR gun or voltage drop test might tell you where there are problems.

Check the big B+ feed cable to the fuse box

Peevarino · Post by **Peevarino** » 27 Dec 2019, 06:55

I’ll definitely check the b+ under fuse box, rain this weekend might keep me from working on it, however. Voltage drop is also on my list, I also still want to try a few different things when starting the car to see if anything changes with headlights off, radio, etc.

Post by **misha** » 27 Dec 2019, 15:34

13.8v at battery terminals and 14.2v on alternator indicates that you have a voltage drop.
B+ from battery to starter is the usual culprit.

Peevarino · Post by **Peevarino** » 29 Dec 2019, 05:02

I’ll check voltage at the starter tomorrow after I drive to work.

For replacing the alt to starter and starter to battery cables, should that be required, do you just cut back the old and run the new along the stock wiring harnesses? Or is there an easier path to run the new cables? I’d imagine running along the old would be cleaner looking at least.

Post by **misha** » 29 Dec 2019, 05:18

I just added a new one from battery to starter.

Just make sure that you disconnect the negative battery terminal before you start the job because you can fry something if you touch surroundings with positive cable if the battery is still connected.

Peevarino · Post by **Peevarino** » 29 Dec 2019, 06:11

Definitely.

I’ve rebuilt battery cables before, but there was a lot more room to work in my 95 F150.

Post by **misha** » 29 Dec 2019, 07:10

There is room....remove the plastic cover which covers the connections and it's literally a 30 min job....if you're just adding another cable.

Peevarino · Post by **Peevarino** » 29 Dec 2019, 11:14

Not room like that truck...

Was replacing upper torque mounts today, gave the pos cable off the battery a little wiggle, it is probably not properly crimped or soldered to the terminal, I think it’s mostly held on by heat shrink.

Will still compare alt to starter and starter to battery voltages tomorrow morning, but I think that’s the culprit for the slow to start, flickering of lights after starting.

Peevarino · Post by **Peevarino** » 30 Dec 2019, 05:58

14.1 at starter after driving to work this morning. With that drop between the starter and battery, I’ll definitely replace or add another cable. It’ll be a week or two before I have the time to do that, so I’ll be back to this thread to report on the early flickering after swapping/adding cable.

I suspect the flickering issue will be fixed after, it makes sense considering the cable is wonky, especially if the car runs off battery at start up and for a short period before drawing power from the alternator, could also be the reason behind the sluggish starting.