Replacing alternator ?s

[WestTexas944s]

Hello I have a 1987 Porsche 944s it has a new battery but the voltmeter is reading low, I has able to jump it to get it started but it took about 20minutes then it started just fine for 3-4 starts but now it won't start again. Any ideas? If it's the alternator how hard is it to replace any one have step by step instructions? Thank you.

[dgcantrell]

You don't need to replace the whole alternator. It's probably just the voltage regulator that slips into the back. Remove the air box, AFM, and cooling duct from the back of the alternator. The voltage regulator is held in by two small bolts and pulls straight out.

There are some brushes on the voltage regulator that can get worn down. The Bosch alternator unit itself is damn near bullet proof. I've put 2 regulators in mine. $40 or so.

[John_AZ]

If you insist on "jumping" the car be prepared to invest in a ECU!



Have the alternator tested at a local auto parts store.

J_AZ

[dgcantrell]

I've had to jump mine many times over the past 24 years, never an issue..

[WestTexas944s]

Is it worth the money to get the genuine Porsche one or would the Bosch brand work just as good

[DannoXYZ]

Make sure the grounds are good on the block & chassis. If they're bad, the starter will use the ground through the DME for powering the starter. Will pretty much melt the circuit-board of the DME in the process.

As for jump-starting, when the cables are in good condition, the wiring/starter/DME cannot tell if electrons are coming through battery-terminals are from that battery itself, or a 2nd-battery a couple feet away. It's a Y-connection, doesn't matter which leg you have, they both meet at the same place and travel through same path. Imagine you removed battery and placed it on the ground in front of car and connected jumper-cables between battery and factory cables. Same exact flow-path once it arrives at the factory battery terminal clamps.

I don't think there's a Porsche alternator. Sure, they may have a Porsche part#, but all OEM ones were made by Bosch.

[WestTexas944s]

Would you happen to know where the grounds on the block and chassis are located?

[WestTexas944s]

Does this sound more like a alternator or voltage regulator issue or a bad ground issue? The car has been driving just fine no indacator lights but last week I noticed that the ac would sometimes fluctuat and yesterday it started just fine but after running for about 2min or do it died I still had power the motor just wouldn't turn over. And for probably the last 3 weeks the voltage gauge would stay more on the low end.

[Sehrgut]

Goofy video, But it shows how easy it is to replace voltage regulator. I replaced mine in about 30 minutes, and it solved the problem right away. Good luck!

https://www.youtube.com/watch?v=Tt39gm6AWQs

[WestTexas944s]

Thanks man I ordered the part and give it a try this weekend. If it doesn't work I will have the alternator tested hopefully have it fixed this weekend I already miss driving that little car.