Hi guys I have just taken my 355 (1995 2.7) out and have an intermittent alternator warning light come on. I have searched and read many articles on how unreliable these are on the 348/355 and there are guides on how to rebuild them on the net. I also see there are problems with broken or missing earth straps causing issues. Highly likely one of these is my problem. However, what I have not seen are the symptoms described other than them breaking down and coming to a stop. I therefore wanted to describe what I am experiencing to see if this is a common symptom or not. When I start the car all warning lights come on and go out as expected. I then go out driving and no alternator warning light comes on until it is nicely warmed up, say 15 minutes after start up. Then the light comes at lower RPMs (under 4000), once I go over 4000RPM the light goes out again. This does not seem to affect the running of the engine, and the car starts fine so it does seem to be charging the battery a bit. I have not managed to get the car on a ramp to check if this strap is there or not yet. Any thoughts and experienced shared would be appreciated.
Alternators are three phase components. The voltage regulator combines the phases and controls the voltage output. The most common failure mode is for one phase to drop out due to failed diodes. Remaining diodes being overloaded will fail shortly. With one phase gone there is still the ability to charge at higher rpm but typically the warning light will come one at idle. You can go through the standard diagnostic voltage tests but best to start making arrangements for a new voltage regulator.
I had this problem when I had a 355. It was the regulator and one of the main causes seems to be that the heat from the headers is continually cooking the alternator. Some guys have fabricated aluminum shields which I heard work quite well at deflecting direct heat. I had mine rebuilt whilst the car was being serviced and the rebuild cost $285 about 3 years ago.
Typical of failing voltage regulator. It is going out when it heats up from use. There are plenty of threads here on obtaining parts and fixing it yourself. I did it preventatively (in car) using the info in the threads. Pretty easy to accomplish. Make absolutely sure you have the added ground strap on your alternator. They did not come from the factory with them, but were often added by dealers during a major service. Ricambi sells the part, it is not expensive. You could make your own with some 10 gauge wire and ring mounts.
First off...I found the posts extremely helpful, as this exact set of symptoms (i.e. Alternator light coming on at low revs after a full warm-up) is what I'm dealing with right now. I have two questions, if anyone can help: 1) Don't laugh...but where is the voltage regulator? Is it integral to the alternator, or is it a separate unit? 2) I'm in Michigan, and I'm planning a shock and bushing service, so the car will be down for a week or so. Does anyone know of a reliable alternator rebuilding service which I can use? Thanks in advance folks!!
Time for a bit of reading...great thread by JM3 about rebuilding and improving 355 alternator http://www.ferrarichat.com/forum/showthread.php?t=124504 Image Unavailable, Please Login
On page 3 of that thread I posted a link to the "how-to" thread with pics on the rebuild. Be sure to read the WHOLE thread be for you dig in. We found that there are some small differences between the alternator housings. If the wrong size rectifier goes in the back cover will touch and can cause a short = not good. So read the entire thread first.
Paul_308 and Ernie; THANKS...I got the parts (ordered direct from Regitar) at total cost of 37.00 with shipping. Took the alternator out (Holy %$#@% that top bolt is a *****!!) and brushes looked great; replaced diode pack and regulator. Took care of the short oil pipe while I was in there...NO MORE OIL SPOTS UNDER THE CAR!! Got everything back together (with rebuilt shocks from Delta Vee...good stuff...and stock springs. Did about 4 hours of spirited yet not-full-out driving with zero problems. Then...last night...I took advantage of empty roads and drove it pretty hard...nothing below 5000rpm for about a half-hour...and the alternator light came back on. My ground strap is in place and is solid...all connections appear good. So...now I'm scratching my head. I'm wondering...is it possible that the half-hour of all-out driving cooked the diode pack and VR again? Or...might I have bad stator windings which might be feeding the diode pack some square or sawtooth waveforms (I'm pretty sure that a condition like that could cook 'em again)? Hmm. Also, I heard about a guy who repackaged the VR and the diode pack to be placed remotely elsewhere in the vehicle to keep 'em cool...anybody hear about this? Also, if anyone knows of a heatshield which I could buy ready-made, let me know before I make one!! Thanks again guys!!!
Check the inegrity of the "sense" wire for the regulator. This small red wire travels adjacent to the main battery cable all the way from the alternator to the positive battery clamp. If there is anything wrong with the integrity of the clamp, a replacement clamp or similar, then the whole deal won't work well. Addendum to the original post regarding rebuilding the alternator: You will note that I had suggested replacing the cover screws with short allen bolts, to facilitate the repair next time around. Over the winter, my Schumacher battery tender lit up a red light, indicating a battery problem with a fairly new battery. I unplugged the charger and went to start the car, almost started but not quite. I jumped in another battery, and started the car. The alternator light came on, the defective Schumacher tender had fried the battery, and the alternator wasn't happy. So.... with allen bolts installed on the back of the alternator, I was able to easily rebuild the alternator IN THE CAR, in less than an hour from start to finish (including jacking up the car and removing the tray)
I just got back from lunch and all the while (even though I was eat-whatever-doesn't-move hungry) I thought about the connector that plugs into the back of the alternator...and I think that's where the wire is, right? It did not snap in with a healthy "click"...so, now, after reading your post, I'm gonna go in tonight and check it out. And those screws? That was the first thing I bought after I read your original post! This Ferrari chat thing is the whip!!! Thanks Again!! Dennis
I had the same issues as you over the last 6 years. 1. The first time I had the alternator rebuilt at a cost of $650 2. Then 2 years later again the same issue so then I spent $350 and it lasted another year. 3. Then I just bought a brand new one and have not had a problem for the last 2 years. I have also put heat shield on as well. I suppose what I am saying is for the price of a new alternator just replace it and be done with it. You can replace voltage regulators and diodes and etc etc but sometimes you end up spending so much time and money that you were better off just putting a new one in. Hope it works out wither way.
Valid point, but we have no idea what parts are being used in your rebuild. One of the issues found in the threads about this, is there are certain parts to avoid, that can cause premature failures. The Regitar parts recommended, appear to last much longer than most other aftermarket parts, and even the oem parts.
