Voltage drop at 5000 RPM's

[heliolps2]

Hey all,

I just completed a 250-mile road trip yesterday, I'm about to pull the Heat exchangers of to update my other post, But I noticed something strange, a low voltage drop at 5000 RPM's, She starts perfect every time in the morning, the voltage shows 13.8 at idle and about the same while driving and drops slightly to 13.6 with the lights on. I first noticed my lights dimmed at higher RPM's when I hit about 5000 RPM's, I plugged in my voltage tester into the cig lighter and the voltage drops to 12.05 to 12. as once below 5000 RPM's it goes back to normal 13.8v. No lights come on in the dash, which I find interesting. I don't know how long it's been doing this, because I don't drive her much at night and not at higher rpm's.

I'm also wondering if the low voltage drop has any effect on the sensors and EZ69 ignition unit* and coil? especially on hard pulls at full boost. Also when the voltage drops it will effect the fuel pump pressure, dropping the fuel pressure making it way to rich in this case,* at 5000 rpm's

I ordered a new voltage regulator, I checked all the grounds to the chassis and battery and the wiring to the starter as well and engine harness plugs . I'm expecting it to be the Voltage regulator. Has anyone experienced this before or can someone test this to see if this happening to your 965, I don't think this is normal? Only because I haven't got any warning light at all.

Your thoughts ?

Helio

[Alan L]

I think your guess is correct. Because the VR is supposed to keep it stable. From memory it works in steps - so part of the range could fail first.
It will cause your pumps to pull more amps as it drops. If you stayed in that state long enough you could blow a fuel pump fuse - they are marginal at best.
But then you would probably have changed gear by then :-)
Alan

[heliolps2]

Update.

I just replaced the voltage regulator, start to finish it took 3 hours and 10 mins, I drove her to work today and everything working perfectly. Yay! Here's what I found, My car has 57000 miles

[reclino]

Wow those brushes are gone. How did the skip rings look? In my 1986 the brushes were fine, but deep grooves in the copper slip rings.

[Alfasrule]

Maybe you play your radio too loud? Joking
That's the culprit ALFA Romeo share the same alternator.
I have 3 in stock for my cars. The regulator shown above.
Must be tight to take 3 hours. One is the max for me.
ALFAsRule!