EEES

Please help! I have a 1999 Porsche 996 C-2 Coupe. It has just over 100,000 miles. When I try to start the car, it does not start. I have tracked back to the starter. I am getting current, but I do not get 12v to the solenoid when I turn the key. I hear the fuel pump prime. All the dash warning lights come on. All electrical work properly, but the starter will not turn and the engine will not fire. I have checked EVERY SINGLE fuse. I even tested with meter for continuity (sometimes a fuse will not look broken even when it is). I also checked and cleaned the ground strap on the passenger side of the engine. All the contacts (engine ground, starter and alternator) look clean and free of corrosion.

Should I look for a starter relay to test? How is this done? What about the clutch pedal switch? Does anyone know how to check or jump the clutch pedal switch? Is there anything I am missing?

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.

Next day, I removed and cleaned the ground strap. Retested it….car started but wouldn’t restart 20 minutes later. Then I removed the starter and alternator. Both were bench tested. Both passed all tests. I bought a starter anyway. After install, the car will not turn over AT ALL. I removed the new starter and took it back to Auto Zone to bench test. It engaged and started spinning and passed all tests. Then I put it back in the car and found 12v not going to the solenoid. So I bought a new ignition switch and installed that. I am still not getting any power to the solenoid.

Please help me get this baby running.

Ahsai

I know you said you checked all fuses but please just check C1 to C4 again.

Remove the two wires connected to the grey clutch switch and just connect the wires together and try again. That will bypass the clutch switch.

Next is to check the starter relay behind the rear seats.

Next is wiring between the relay and the starter solenoid.

Once you get the car started, you can do voltage drop tests on the whole electrical system (including the Y" starter cable) to see if you are losing any voltage on any cables.

The ignition switch is also known as a common failure.

EEES

Ok, I will check C1 - C4 again. Than I will bypass the clutch switch.

And if those fail, I will check the starter relay. Is it hard to find? I don't know how to find it. I have been unable to find a DIY or a tutorial to remove whatever is necessary to gain access to the starter relay.

Thanks for your help!

Ahsai

Just fold down the rear seats, lift up the thick carpet (carpet needs to buckle up in the middle), remove the driver's side aluminum panel, the relay panel is under it.

The start lock relay is #7 here http://www.renntech.org/forums/topic...tion/?p=221230

Better get the wiring diagram to check the pinout of the relay.

BBA

Being that you have hard starts when hot, I would check the resistance in the engine ground cable and positive cable from the alternator. Both are known to develop high internal resistance that leads to hard starting, charging, or other issues. If you search the forums there are multiple threads on both.

sjg1138

I echo BBA. Even though the cables and contacts can look perfectly clean, they often become corroded on the inside. Especially right at the starter.

EEES

Thank you for all the great advice. I rechecked C-1 through C4 and actually hooked up each fuse to the full meter to check for continuity. All the fuses are good. Then I went to look at the clutch pedal switch. I jumped the clutch pedal switch and the car still not start. Then I check the relay. As soon as I engage the key and put it in the accessory position, the starter relay clicks. When I turn the key to engage the starter, nothing happens. The starter relay doesn't click and everything is silent.
I was unable to get a wiring diagram to jump the relay. I figure I would just ask for advice to see if it sounds like this would be a bad starter relay.

It sounds like somewhere between ignition and the starter relay, there is an issue. Is it possible that I reinstalled the ignition switch incorrectly? There were only two set screws and it was very straightforward to plug-in.

FRUNKenstein

Although I sound like a broken record, it bears repeating: electrical gremlins in a 996 are often caused by a bad ignition switch. It is a $12 part that takes under an hour to replace, and some can do it in less than 20 minutes. So, start by first replacing any part that you suspect may be bad that costs less than $12 and takes less than an hour. Once you have replaced all of those sub-$12 parts, do the ignition switch next.

Ahsai

The way your relay clicks sounds normal. You can remove the relay and put a jumper (one that's good for a few amps) between pin 30 and 87 then try to crank. If that doesn't work, you can eliminate the relay and it's one of the follwings:
- ignition switch not giving power
- a break between the ignition switch and the relay
- a break between the relay and the starter solenoid

When you crank, 12v goes from the ignition to pin 30 of the relay. Pin 87 is connected directly to the starter solenoid. When the relay clicks, it connects pin 30 and pin 87 to prepare for your key to hit the crank position.

Of course you can check if you get 12v at pin 30 when you crank and if you don't see it, it's one of the first two above.

Wiring diagram here btw http://kt.qclt.com/porsche/manual2/p..._1999_2000.pdf

Schnell Gelb

EEES,
Did you check for corrosion inside the main power cables -mentioned above? You may have to strip back some insulation at both ends of each cable.If it is all green+ white powder -replace them. Or at least bypass them temporarily with a big jumper cable to prove the point. The corrosion problem is common as mentioned above.

EEES

We confirmed that the relay is getting power. My dad is electronic genius, serving as an engineer for a radio station, and he came over and we checked. You were right the relay is getting 12 V. As we connected the relay with a safety pin, it became glowing red almost instantly. It appears that there is no corrosion on the cables. It looks like we're getting current to everything except for the starter solenoid. I have suspected issues with my key for a while. I was going to buy a whole new one and have it reprogrammed. Is it possible that the mobilizer would prevent the starter from working? Or would that have caused the current to stop long before the relay?

Ahsai

The immobilizer sends power to the relay only if it detects the correct key is used. Since your relay clicks, that means the immobulizer is happy and all you need is power from the ignition to reach the relay.

Were you able to make the engine crank with the jumper in place of the relay? Have you bench tested the relay?

You are in good hands anyway with you dad being an engineer.

EEES

Sorry my previous post was almost unreadable (thank you, Siri). Anyway, the starter solenoid got no current with the jumper in place of the relay.

I'm stumped. My dad told me to just take it to he dealer because I was likely to just add another unknown variable if I keep messing around.

Any input would be greatly appreciated.

Ahsai

I reread your edtied post #11. Just to confirm, you removed the relay, jumped the pins corresponds to pin 30 and pin 87 on the relay socket, then you turned the key to crank. Jumper then gets red hot and starter does not crank.

If the above is true, you do have current going through the stater solenoid but the stater is not turning therefore your starter solenoid is bad. You can remove the starter and get it bench tested to confirm.

I don't understand though why you said you have no current but yet a red hot jumper.

EEES

You are correct. The jumper gets red hot, but the starter does not crank. Even though the jumper gets red hot, 12 v does not show up at the starter solenoid. As soon as I installed the starter a few weeks back, that's when this issue started. I immediately removed the new starter and took it to have it bench tested. It passed all tests, so I know the starter does work. Then I put the starter back in the car, and I have been trying to troubleshoot down the root cause of the non-starting issue ever since. I can't figure out why the jumper gets red hot at the relay, but there is nothing at the starter solenoid. The starter is getting 12 V, but the solenoid is getting nothing.

Too weird
??????
Is there anything else back there (starter and alternator) that I could've messed up when I removed and reinstalled the starter and the alternator a few weeks ago?