High RPM light flicker
#1
Rennlist Member
Thread Starter
High RPM light flicker
I just got done putting the engine in (again)
During a nighttime shakedown run,I noticed at over 3000 RPM I get a light flicker in the dash. Can replicate this in garage in neutral.
Alternator belt is tight
Voltage regulator on the alternator has been replaced in last 300 miles.
Alternator was checked out at a shop that rebuilds alternators (not a Pep Boys etc but an actual electrical shop). They said alternator (with new voltage regulator) tests good.
Battery tender has given me a flashing light saying "check/replace battery".
Battery died after two days of sitting.
Battery is a factory spec Bosch.
Voltage is 13.8 at the jump post with lights, fan etc on. 14.0+ with no load.
Now the questions:
I can guess that the battery is bad but why would my lights flicker? Is this due to alternator trying to compesate for bad battery?
I have seen on my searches that the Red Optima is a good battery. Any reason not to use this battery?
Thanks in Advance.
During a nighttime shakedown run,I noticed at over 3000 RPM I get a light flicker in the dash. Can replicate this in garage in neutral.
Alternator belt is tight
Voltage regulator on the alternator has been replaced in last 300 miles.
Alternator was checked out at a shop that rebuilds alternators (not a Pep Boys etc but an actual electrical shop). They said alternator (with new voltage regulator) tests good.
Battery tender has given me a flashing light saying "check/replace battery".
Battery died after two days of sitting.
Battery is a factory spec Bosch.
Voltage is 13.8 at the jump post with lights, fan etc on. 14.0+ with no load.
Now the questions:
I can guess that the battery is bad but why would my lights flicker? Is this due to alternator trying to compesate for bad battery?
I have seen on my searches that the Red Optima is a good battery. Any reason not to use this battery?
Thanks in Advance.
#2
Instructor
I have an Optima in a Lotus that gets driven less frequently and it is a great battery. Long life, ability to stay charged and get re-charged easily. It is excellent for a car that is not run every day, but the down side to it is cost.
In my 91 S4 I have a Walmart battery in the correct size that cost about $80. It is almost two years old and has been perfect. I see no need to go the Optima route in this car.
In my 91 S4 I have a Walmart battery in the correct size that cost about $80. It is almost two years old and has been perfect. I see no need to go the Optima route in this car.
#4
Rennlist Member
Thread Starter
Andrew. I have regular lights. Headlights flicker, dash lights, everything.
#5
Rennlist Member
Thread Starter
That's why I am wondering if it is due to the battery or could the alternator have died between last week and now. It is about 5 years old or so (guess by not looking at receipt). Also like I said, new voltage regulator on it.
#7
Rennlist Member
Rennlist Site Sponsor
One possibility is that the brushes might be bouncing on the slip rings. If the rings are worn or out of true a bit, the brush springs might be able to cope at lower RPM levels, but bounce off at higher RPM levels.
Trending Topics
#8
Rennlist Member
Thread Starter
I'll put another voltage regulator in and see what happens. If it doesn't get better, I'll get a rebuilt alternator from Roger and see what that does.
#9
Rennlist Member
Thread Starter
I had the battery tested over lunch. 690 CCA battery tests good putting out 740 CCA. Guess I can eliminate the battery from the equation.
New voltage regulator will be here tomorrow.
New voltage regulator will be here tomorrow.
#10
Rennlist Member
Thread Starter
I put in a rebuilt Bosch alternator from Roger. Problem is gone.