Car won't start. Not getting 12v power to starter solenoid
#46
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
BTW, I've attached the relevant wiring diagram here for your reference (with some drawing of my own).
"YE" means yellow. The number next to the color is the cross section surface area of the wire. e.g., "4.0" means 4 mm square. You can see there are two thinner "2.5" wires between pin 87 and the solenoid. The reason is the "X59/1" connector can only carry wires of that size so we need two "2.5" in parallel to match the "4.0" wire from the ignition switch to pin 30 of the relay.
"4.0" is good for 32A and "2.5" is good for 24A.
My current suspicion is you have a short to ground on the wires between pin 87 and the solenoid or your autozone starter (1.1kW) is too weak to turn the engine. The stock starter is rated at 1.7kW.
"YE" means yellow. The number next to the color is the cross section surface area of the wire. e.g., "4.0" means 4 mm square. You can see there are two thinner "2.5" wires between pin 87 and the solenoid. The reason is the "X59/1" connector can only carry wires of that size so we need two "2.5" in parallel to match the "4.0" wire from the ignition switch to pin 30 of the relay.
"4.0" is good for 32A and "2.5" is good for 24A.
My current suspicion is you have a short to ground on the wires between pin 87 and the solenoid or your autozone starter (1.1kW) is too weak to turn the engine. The stock starter is rated at 1.7kW.
![Name: Porsche-996-starter-circuit.jpg
Views: 10246
Size: 70.1 KB](https://rennlist.com/forums/attachments/996-forum/926445d1428512968-car-won-t-start-not-getting-12v-power-to-starter-solenoid-porsche-996-starter-circuit.jpg)
#47
Instructor
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I did not read the whole story, but had a starting problem, on my 84 3.2 Carrera, and it was just a VERY dusty , dirty, starter, run fine after a good clean up! done in S Luis Obispo. Cal. during a cross country /camping road trip back in 07, That was ONE great trip !! mmmmmm
#48
Racer
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Ahsai! You are outdoing yourself with this thread and spiralling that wagon towards a final solution very nicely for this poor guy.
Good on you and thanks for the many tips throughout.
Good on you and thanks for the many tips throughout.
#49
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Anytime! Just trying to help out here. I think his case is quite atypical yet interesting.
#50
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Rereading post #1:
I put my $$ on bad "Y" cable. Corrosion under the insulation by one of the crimped connectors.
"Here is the history. Last summer, the car would start VERY VERY slowly once it was warm. As I understand, heat causes resistance, and after you drive the car for some distance, restarting can really stress an old starter or appear from a poor ground strap."
"This winter, I attempted to start the car in the cold. It started fine. Upon restart, it wouldn’t turn over enough to start the car. I had the car started with the aid of jumper cables, and I drove it to Auto Zone. Battery was charged and tested…passed with flying colors. Drove car home. Next day, car started but wouldn’t restart. It was the SAME THING, so we jumped it and I drove it home."
Rereading post 15:
Sounds like something connected wrong, or shorted to ground during installation.
"As soon as I installed the starter a few weeks back, that's when this issue started."
I put my $$ on bad "Y" cable. Corrosion under the insulation by one of the crimped connectors.
"Here is the history. Last summer, the car would start VERY VERY slowly once it was warm. As I understand, heat causes resistance, and after you drive the car for some distance, restarting can really stress an old starter or appear from a poor ground strap."
"This winter, I attempted to start the car in the cold. It started fine. Upon restart, it wouldn’t turn over enough to start the car. I had the car started with the aid of jumper cables, and I drove it to Auto Zone. Battery was charged and tested…passed with flying colors. Drove car home. Next day, car started but wouldn’t restart. It was the SAME THING, so we jumped it and I drove it home."
Rereading post 15:
Sounds like something connected wrong, or shorted to ground during installation.
"As soon as I installed the starter a few weeks back, that's when this issue started."
#51
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Yes, the "Y" cable and ground cable are not ruled out at this point yet. To prove those cables are bad, a voltage drop test on the cables is needed, which requires large current flowing through the cables. Without the starter or the engine running, the only way that I know of is to put load on the engine end of the cable (e.g., use a carbon pile battery load tester). If the starter is not getting enough current, it will not spin and that may blow the relay.
The two terminals on the starter are of two different sizes so I don't really think you can put the wires on wrong. OP is going to test out the short to ground solenoid wire.
If there is NO short, the problem has to be in the starter and/or the cable(s). The OP already confirmed the engine can be turned by hand so it's not seized.
The two terminals on the starter are of two different sizes so I don't really think you can put the wires on wrong. OP is going to test out the short to ground solenoid wire.
If there is NO short, the problem has to be in the starter and/or the cable(s). The OP already confirmed the engine can be turned by hand so it's not seized.
The following users liked this post:
John Fleitz (11-08-2020)
#53
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
So do you guys think the "Y" cable can also explain the car blowing up the relays? I think it's possible but not 100% sure. At least I have not heard of such cases reported online.
#54
Drifting
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
It is always the Y cable and the ground strap.
So has anyone got a suggested upgrade for theses two problematic parts? More corrosion-proof connectors ,better sealed insulation at the ends of a ground cable.Use an old fashioned braided strap so you can see corrosion ?
Ashai - you are just amazing at helping to resolve these obscure issues. Thank you !
So has anyone got a suggested upgrade for theses two problematic parts? More corrosion-proof connectors ,better sealed insulation at the ends of a ground cable.Use an old fashioned braided strap so you can see corrosion ?
Ashai - you are just amazing at helping to resolve these obscure issues. Thank you !
#55
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Ahsai,
I haven't pulled a 996 starter yet. Is/are there any insulated washers/bushings that keep the hot feed from touching the starter/solenoid housings?
I'm thinking something like the insulator on the points spring stud that would drive folks crazy if the spring was slid behind instead of in front causing a short, no spark, that kept the coil energized even when the points opened.
I haven't pulled a 996 starter yet. Is/are there any insulated washers/bushings that keep the hot feed from touching the starter/solenoid housings?
I'm thinking something like the insulator on the points spring stud that would drive folks crazy if the spring was slid behind instead of in front causing a short, no spark, that kept the coil energized even when the points opened.
#56
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Ahsai,
I haven't pulled a 996 starter yet. Is/are there any insulated washers/bushings that keep the hot feed from touching the starter/solenoid housings?
I'm thinking something like the insulator on the points spring stud that would drive folks crazy if the spring was slid behind instead of in front causing a short, no spark, that kept the coil energized even when the points opened.
I haven't pulled a 996 starter yet. Is/are there any insulated washers/bushings that keep the hot feed from touching the starter/solenoid housings?
I'm thinking something like the insulator on the points spring stud that would drive folks crazy if the spring was slid behind instead of in front causing a short, no spark, that kept the coil energized even when the points opened.
Anyway, the latest is he was able to start the car with the autozone starter and all the stock cables connected with the addition of a jumper cable connecting the starter 12v power post and the engine compartment "+" jump start terminal, essentially bypassing the y-cable (if it's bad). However, later on the car also started after he removed that jumper cable
![hiha](https://rennlist.com/forums/graemlins/roflmao.gif)
Anyway, I chalked that up to an intermittent y-cable failure and suggested he replace it.
![Name: image.jpg
Views: 3009
Size: 82.2 KB](https://rennlist.com/forums/attachments/996-forum/927257d1428730403-car-won-t-start-not-getting-12v-power-to-starter-solenoid-image.jpg)
#57
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
It is always the Y cable and the ground strap.
So has anyone got a suggested upgrade for theses two problematic parts? More corrosion-proof connectors ,better sealed insulation at the ends of a ground cable.Use an old fashioned braided strap so you can see corrosion ?
Ashai - you are just amazing at helping to resolve these obscure issues. Thank you !
So has anyone got a suggested upgrade for theses two problematic parts? More corrosion-proof connectors ,better sealed insulation at the ends of a ground cable.Use an old fashioned braided strap so you can see corrosion ?
Ashai - you are just amazing at helping to resolve these obscure issues. Thank you !
The y-cable is a different story. It's cooked by the engine all the time. I already had two failed on me. Both were the latest version. The second one failed in less than 2 yrs and it was still shinny when I removed it! If it fails again, I will put in a new one with all the crimps sealed with dielectric grease. The good news is I can replace that cable in an hr or so now. I replaced my alternator in 20min last time
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
#58
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Now I'm wishing I sealed the crimps on my Y cable when I put it in. I did put dialectic grease down in the area between the insulation and the cable with the idea being that the grease would keep out the moisture and help prolong the life of the cable.
Maybe sealing the crimps completely would solve the problem. There has got to be a way to make a Y cable that won't fail.
Maybe sealing the crimps completely would solve the problem. There has got to be a way to make a Y cable that won't fail.
The ground cable is not so much of a problem and usually it's due to age so replacing it with the stock one should last you a long long time.
The y-cable is a different story. It's cooked by the engine all the time. I already had two failed on me. Both were the latest version. The second one failed in less than 2 yrs and it was still shinny when I removed it! If it fails again, I will put in a new one with all the crimps sealed with dielectric grease. The good news is I can replace that cable in an hr or so now. I replaced my alternator in 20min last time![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
The y-cable is a different story. It's cooked by the engine all the time. I already had two failed on me. Both were the latest version. The second one failed in less than 2 yrs and it was still shinny when I removed it! If it fails again, I will put in a new one with all the crimps sealed with dielectric grease. The good news is I can replace that cable in an hr or so now. I replaced my alternator in 20min last time
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
#59
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Looks like pretty standard internal contact solenoid activated lever arm starter.
Hope he posts pics of the "Y" cable so we can see corrosion/shorts etc...
Hope he posts pics of the "Y" cable so we can see corrosion/shorts etc...
#60
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Anything new here? I am getting ready to head down this rabbit hole myself. My 2004 GT3 has intermittent starter issues. I've replaced the ign switch, battery, and checked both ground straps. All good. The car does start, but sometimes it takes 5,6,7 attempts for it to catch. The battery maintains a charge, so I'm now thinking it's a starter issue. Thanks for any updates to this thread.