Just had Alt rebuilt...still nothing!

What is voltage coming out our big wire AT the back of alternator?

 

I had my alternator rebuild although they said it was fine. I took apart, cleaned & tightened all connections not just checked them. There is not much to the charging system but here are some of the things to clean etc.

Alternator (Sounds like this has been done)
Grounding of altenrator to motor (I cleaned up the bolded areas before putting it back together)
Battery (you can pull it & have it checked at a shop)
Battery terminals (clean & tighten)
Connections to the alternator
Connections at the starter
I checked continuity + cable from battery to starter
Ground from engine to chassis (mine was oily so I cleaned & then brushed it good).
Ground at front
Battery disconnect switch & cable (check continuity & wiggle it around).

Does your battery light go out when you start the car & blip it over 2000RPM?

Hopefully you can track it down....Brad

 

Light could be a problem with the small wire to the back of the alternator.

Disconnect is to the left of the spare tire well, a red plastic block with braided wire to it. Not a switch, just a big red push on connector. Disconnect grounds the battery when connectors are mated.

 

Check the bulb in the ammeter is OK. If this bulb is faulty then the alternator will not charge the battery.

 

Good point,
The bulb supplies power to the alternator's field coil until the alternator is rev'd enough to start self-energizing the field. That's why I suggested cking the small wire to back of alternator, if it's unplugged, field doesn't get powered.

 

wrt voltage at the coil terminals, that depends on which wire you pulled. One of the wires goes to the diagnostic connector, and the other goes to the ecu connector.

If you disconnect the diag connector wire, no problem. If you disconnect the ecu wire, you have disconnected the coil. Which wire is which you can only tell using an ohmeter and probing for the other end in the ecu or diag connectors. Of course, if both are connected you don't care which wire is which.

Your owners manual has a schematic. If you want to make sure you have no wiring/connector issues, use an ohmeter to verify the circuits.

ditto for the alternator light. The wire verell mentioned on the alternator goes all the way to the lamp (at least, it does on the 328...you'll have to experience the joy of following lines on the schem to verify the same for the 308qv - it's easiest to make a big copy and highlight the lines).

If it is the same, however, then you have an interesting problem. Since the lamp lights when the key is turned, the wire from the alternator should be ok. The problem would be in connectors between the lamp and the fuse box.

It's also possible that your alternator/voltage regulator doesn't need the rpm blip to get excited, in which case the light won't come on. Probe the verell wire terminal on the alternator with a voltmeter. If you are seeing +13V or so with the engine running, then the light stays off.

 

Same on all 308s (4Vs & 2Vs) w/BOSCH alternators.

 

I guess as usual I wasn't clear, so I'll make things worse...

There is a set of two connector tabs on each side of the metal coil frame. Electrically they are the same tab. There is just two of them so two wires can be tied to the same spot.

If you look on the metal frame, one set of tabs is labelled #1, and the other is #15. According to the US qv manual, the solid yellow wires are the +12V supply from the fusebox (or wherever...I can't follow the lines in the manual). All the solid yellow wires should be connected to the #15 terminals. If you pull the solid yellow wires one at a time and measure the voltage on the coil terminals, eventually you will pull the yellow wire that was powering them all.

In the picture you have, the disconnected yellow wire probably is the 12V from the fusebox, so probe the wire.

Looking at the picture again, though, there does seem to be a wiring problem. Either the schematic and the car wiring colors don't agree (which has been known to happen), the euro wiring is different, or the wires are connected wrong on the coils.

The schematic says all the solid yellow wires connect to the #15 terminals.
You should be good there based on your voltage measurements. There is only a 1/12 chance of screwing it up. The screw up would be if the wire from the fusebox and the wire to the diag connector were on the same coil. That would mean the other coil had a short yellow jumper wire connecting to itself.

If the solid yellow wire thing isn't making sense, then think daisy chain.
It goes fusebox-> coil A -> coil B -> diag connector. Which coil is A and
which is B doesn't matter.

The green wires are also supposed to be daisy chains, as are the two yellow/black wires. However, it does matter for these chains which coil they are connected to.

Put another way, both green wires should connect to the #1 terminals on the SAME coil, and both the yellow/black wires should connect to the #1 terminals on the other coil.

You have a green and a yellow/black wires going to each coil. In this case, it's a crap shoot whether it works.

One of the green wires goes to the diag connector, so it's essentially useless.
The other green wire goes to one of the ecu's. Call that one the "hot" one.

Same deal with the yellow/black wires. If you get lucky and have the hot green wire on the correct coil, and the hot yellow/black on the other coil, then things will work (except the diag connector, but nothing is attached to it) ... if the two hot wires are on the same coil, you are dead, and hopefully you haven't damaged the ecu's (not likely to damage them, but you would be sending sparks to the cylinders at odd times).

The other little problem is whether the green wires go to the front bank coil or the rear bank coil. Schematic says that the green wires go on the coil firing cylinders 1-4, which is the right bank, the rear bank, the destra bank, or the one closest to the trunk - call it what you want.

Assuming the coil the arrow in your pic is pointing at is connected to the front bank, that coil should have two yellow wires on one side, and two yellow/black wires on the other side. The other coil should have both the green wires.

Also check the coil ground(s).

Hopefully verell or someone with a qv can verify the wiring is wrong, or you can do it yourself by pulling the connector from the ecu's and figuring out which wire is connected to pin 11 on each of the ecu plugs. Pin 11 is at the end of the connector, so look at the wire colors to figure out which ecu/pin to poke.

 

i get confused easily so... i also seem to have an intermittent light alternator problem but my battery does seem to be getting charged. Please explain what in the fuse box fixed your problem. Many thanks as all help is always appreciated.

 

It sounds to me like you may have a short in your charging system. First figure out why it won't start, then with the engine running figure out the charging system. Put a charger on the battery until you can get the charging system sorted out. I would start out by looking for worn wires that are rubbing against the car. One of those wires might be connected to a wrong terminal causing the same symptons.

I say this in general terms because I'm no Ferrari mechannic.

Don't try to drive it on the battery charger. ( G R I N ) You'll run out of extension cord. ( M o r e G r i n s )

Bob Wassam