Headlights pulsing

[Cool Jesus]

Thought I'd start up a thread on this topic as there didn't seem to be any discussion relating to it posted here. I imagine its not specific to the 147 either, so any model with this pulsing/flickering headlight issue would be relevant to the thread.

The 147 has developed a pulsing in the headlights which seems to dissipate once the car has warmed up. I'd even go so far as saying the engine idle also pulses???

From what I've read, I may need to look at the alternator and/or rectifier. I have a spare off a low K parts car to swap in but, thought I'd see if anyone else has had this issue? How involved is the rectifier swap?

Apart from the alternator, I'll check engine/alternator grounds, battery condition and battery leads.

[colcol]

The alternators in twin sparks and JTS's are so hard to change, if the alternator is faulty, i would put a new one in, the alternator lives at the back of the engine on the drivers side, would be easier with a hoist, so you could attack it from underneath, if you were to pull the alternator out and it was faulty, i have seen new ones on ebay for $200-$300, if i didn't take it out myself i would get an Alfa specialist to do it as they would have worked out how to do it by now, the Auto Electricians would be fumbling around, unless they are an Alfa Auto Electrician.
Check all the earths and power leads before looking at the alternator, Colin.

[Cool Jesus]

Yeah, fortunately I do have access to a hoist, sounds like i'll have to book it into my schedule somewhere from what ive read. The 2nd hand unit I have, has done less than 25K kms, so im assuming its a runner. I've read about the rectifier failing on the alternaters, giving that pulsation effect in the headlights. I take it its not worth just replacing the rectifier? Considering the cost and effort I guess its sounder/wiser to just replace entirely.

[colcol]

If it has only done 25,000 klms, then it should be ok, as its not like its a 33 and a 10 minute job, on a 147 or 156, you would need to take your long service leave, hopefully it will be the same rating and brand, unlike some old Alfa Romeo's that could be Bosch, Ducellier or Magnetti Marelli, with different wiring and mounts, Colin.

[Cool Jesus]

Your certainly not selling the work up here 
Its a two year build difference and haven't had any fitment issues thus far with parts swapping. fingers crossed. will report back on the repair once I get to it. When I get a moment I'll check the easy fixes first as mentioned (ie connections, grounds, etc) may save myself a bag full of swear words in the work shop.

[shiny_car]

I presume you don't have a doof doof subwoofer pounding away in the background.  Though point being, is there any additional heavy loads on the power system (stereo, cabin fan on full, demister, aftermarket electronic components, etc).

'At idle', the engine revs will be low, and thus the alternator output will be low. As such, it could be quite normal. Ensure the engine revs are as expected for idle (quite likely to be fine, but worth ensuring), and not 'too low'.

Is the battery healthy? Whilst the alternator provides the power when the engine is running, a dodgy battery will become an unnecessary 'load' on the alternator (ie: the battery is sucking juice in an attempt to recharge).

For sure, check the main engine bay groundwires: battery NEG to chassis to engine block (continuous thick wire).

If you have a multimeter, measure and observe the voltage (eg: probe the battery terminals). Would be interesting to see how low it's dropping.

[Cool Jesus]

The 147 is stock standard. I'd bling it up but the daughter treats it like crap, so I'm only maintains it and ill spend money on my other motors instead. Although I'd like to do up the 147
Good point about the battery, ill check it and do the easier bits as has been discussed. The alternator swap seems labour intensive and can be a last resort. The owners before me did absolutely no maintenance on it, hence the cheap purchase price, so it wouldn't surprise me if the battery wasn't up to scratch. Never a dull moment with four cars on the road.