No charge and no start

[DeRRis]

Originally Posted by Luccia at Pelican Parts

whoo-hoo go Pelican community! So happy they were able to help you find the culprit. Seems to be a popular discussion in our electrical troubleshooting article here as well: Porsche 911 Electrical Problem Troubleshooting | Pelican Parts DIY Maintenance Article. Glad you got it figured out and I do hope you enjoy your trip through the Alps!

Thanks Luccia,

I try to help help here when I can and it sure is nice to be helped

The trip through the Alps will be epic. We are going to do all the great passes like Fluëla, Furka, Nufenen en Stelvio. In the weekend we'll be visiting the Concorso d’Eleganza Villa d’Este at lake Como in Italy.

[Luccia at Pelican Parts]

Originally Posted by DeRRis

Thanks Luccia,

I try to help help here when I can and it sure is nice to be helped

The trip through the Alps will be epic. We are going to do all the great passes like Fluëla, Furka, Nufenen en Stelvio. In the weekend we'll be visiting the Concorso d’Eleganza Villa d’Este at lake Como in Italy.

Oh my gosh! I will be just missing you as I'll be in Lake Como next week and then headed to Modena (where my family is from) for the weekend! How fun!

[T77911S]

as resistance goes up, current goes down. the starter NEEDS a certain amount of current. or you can think of it as it needs a certain amount of power. voltage times current = power. resistance also causes a voltage drop. heat is the result of resistance. that's why your fuel pump fuse gets so hot. the pump pulls a lot of current, add the crappy fuse holder and resistance and you get hot fuses.
this works both ways, charging the battery and the battery providing power, which it is limited to.


trying to keep it simple, so YES, the 2 batteries do "overcome" the resistance due to the fact that there is now nearly twice as much power available.
if you want to get technical with formulas I can do that. been an electronics tech for some 30yrs now and also did auto electric work for a living.

[DeRRis]

I consider myself a good mechanic (wrench). However electrics was never my strong suite so I’m glad you guys pointed me in the right direction. So no need to go all technical on me If it works I stop asking questions Sir

@ Luccia, have fun in Italy and watch out for those pesky Ferrari’s in Modena

[mysocal911]

Originally Posted by T77911S

trying to keep it simple, so YES, the 2 batteries do "overcome" the resistance due to the fact that there is now nearly twice as much power available.
if you want to get technical with formulas I can do that. been an electronics tech for some 30yrs now and also did auto electric work for a living.

Not really! The second battery bypassed the bad ground cable. In both cases the voltage was the same.
The OP would have found the problem sooner by just connecting the jumper battery ground directly to the chassis.

From the OP: " I changed the Battery ground cable,"

[Bob Kontak]

Originally Posted by mysocal911

The OP would have found the problem sooner by just connecting the jumper battery ground directly to the chassis.

Yes, Sir.

Have also seen smarter guys connect the engine to the chassis with jumper cables when battery (and connections) was fine but the main engine ground strap was green (and on it's last leg) from corrosion. This was a BMW. The 911 strap is more robust.

[Bob Kontak]

Originally Posted by DeRRis

So no need to go all technical on me If it works I stop asking questions Sir

@ Luccia, have fun in Italy and watch out for those pesky Ferrari’s in Modena

Let's sum this up. Pretty Luccia, and not so pretty with hairy legs, T77911S.

Where's the love, DeRRis?

All the best and good job!

[DeRRis]

So the drama continues. She car won’t start anymore. Not even with jumper cables. It will start if I bump start the car and then she runs fine. Won’t charge more than 13.6 volts at the battery.
I’ve tried a new starter and all she does is click.

This is what I’ve done/replaced:

- New starter motor
- New dynamo
- New ground strap gearbox/body
- New battery ground cable
- New battery
- New pulley belt
- Cleaned the grounds on the body

So why won’t she start? I’ve missed my trip to the Alps and I’m getting pretty frustrated with her....

[jlex]

Looks like you've already checked out many of the electrics... may be the ignition switch. Will the starter turn it over if you jumped the lugs at the back of the starter? Make sure it's out of gear if you try that. Are you getting power at the starter when you turn the key? Get your multimeter out and check while your helper turns the key to the start position.

[T77911S]

he fixed it

[DeRRis]

Originally Posted by T77911S

he fixed it

I had fixed it or so I thought. The problem came back.

[DeRRis]

Originally Posted by jlex

Looks like you've already checked out many of the electrics... may be the ignition switch. Will the starter turn it over if you jumped the lugs at the back of the starter? Make sure it's out of gear if you try that. Are you getting power at the starter when you turn the key? Get your multimeter out and check while your helper turns the key to the start position.

The yellow wire has power when I turn the key so the ignition switch is ok.

If I hook up a second battery straight to the starter the starter will turn.

[jlex]

Did someone at some point in time hook up a hot start relay? What's the voltage reading from the ignition wire and the voltage reading on the battery line? May be just a shade under what it need to take to crank that starter.
My '88 wouldn't start about 1 time out of 10; starter would just click. Was on the verge of replacing the starter, but I decided to do the easy stuff first: replaced the ground cable at the transaxle even though it looked good. Bingo... it's been perfect ever since. Just the slightest increase in voltage may cure the problem. Corroded cable from the battery or line from the ignitiion switch causing a bit too much resistance?

[DeRRis]

It was the plus cable from the starter to the battery. I hooked up one under the car and she fired right up. So I replaced the plus cable and now she’s good again