ok, so fitted new alt and still doesn't work..what now?

[mattyc]

Right, fitted new alternator, double checked the wiring and now I have a different fault. Before I had the alt light on when the car was idling and it went out when I revved up the engine but there was no charge. Now, with the new alt, I have no light, even when I switch on the ignition and still no charge. I've checked all the wiring and it seems ok, what now???? Could I have damaged the alternator fitting it? Any other ideas anyone please? It's a 1988 911 SC Targa, please help!!!!!!!!!!!

[Early_S_Man]

An '8??? SC?

Integrated, or remote-mounted regulator? Three wires, or four to the engine harness from the alternator?

[911mot]

bulb blown?

[5speed]

Yeah check the bulb to see if it got blown, the alt will not charge without this bulb. It should light up with the key in on position and engine not running.

[mattyc]

yeah it could be that as it doesn't light up when I switch on the ignition without engine running. Sounds a bit strange that the alt wont work without the bulb working though. Is it wasy to check/get to?

[mattyc]

it's the 4 wire version of the alt, with the integrated regulator

[911mot]

The alternator needs the live that comes through the bulb in order to start charging.
If the bulb is OK connect the blue wire at the alt end to earth.
The ignition light should come on.
If it does, the new alternator is no good.
If it does not come on recheck bulb and fuses

[mattyc]

I guess to check the bulb I have to just pull the gauge out of the dash? That's the easiest thing thing to do as I've put the alt back together now! If the bulb's good I'll pull it all apart again and get another alt. Thanks for your help!

[911mot]

I think you can access the bulb under the hood. I maybe wrong though!

[mattyc]

Right, glad you told me that before I tore the dial out. The bulb's my first port of call tomorrow morning anyway. My misses wil leave me for sure if I go out in the garage and start sorting it now! She's just jealous!

[Early_S_Man]

Matt,

The alternators with remote regulators use four wires ... Red, Black, Brown, & Blue.

The Valeo and Paris-Rhone versions with integrated regulator only use three wires ... Red, Brown, and Blue!

Here is a thread that may be some help:

Looking for Early S Man

Here is a bulletin related to the upgrade to the alternator with integrated regulator:

[mattyc]

but but but....mine has a red, a blue and 2 browns. It's the Valeo unit that I've just bought., the 90 amp unit for the 3.2 engine.

[Early_S_Man]

Both Browns are ground, and considered electrically the same cable or wire ...

[mattyc]

aha! that'll be it then, I reckon I must have somehow managed to blow the bulb when I fitted the new alt. Thanks for all your help!

[911mot]

The blue wire goes to pin 11 in the engine bay multiplug (on my euro 84). You could disconnect the L/H engine harness multiplug and run a short wire to ground from pin 11 on the chassis half of the multiplug (engine side has pin numbers on it) to earth to check for voltage from the bulb. Ignition must be on.

[ZOA NOM]

be sure to disconnect the battery before you disconnect the wires to the alt. reconnecting the battery should be the last thing when you're finished.

[mattyc]

ok, the bulb was fine but still does not come on with the ignition. Can anybody tell me if it's fused (so I can check it)????

Failing that I'll have to pull the alt out again and check the blue wires for integrity I guess???? Anybody help???

[mattyc]

sorted it. The new alt was knackered so I replaced it with a new one, all works fine now. Thanks to all for your help and support on this first job on my first Porsche! Cheers.