cobalt

Working on a friends C2. It has been having a problem starting lately. Turn the key and I hear a single click and all the dash lights go dead and nothing happens. Not even the slightest effort from the starter. I can get it to turn over with a charger on 40 AMPS which I don't like to do but it is the only way it will start. It starts and runs without issue this way so I discounted the alternator. There are no strange smells or obvious issues.

I pulled the good battery out of my C2 and tried it with the same results. My C2 cranks over within a second of turning the key. So onto the ground straps. I removed and cleaned all the contacts. I replace everything and no change. Now my battery is showing weak when I test it. I am assuming which could be my mistake that it isn't the starter switch since it cranks with a charger.

I think I have exhausted most of the problem areas but clearly there is an issue I am missing. Any help would be appreciated.

Spyerx

Ignition switch or a relay in the circuit path.
IIRC, when turned fully will disable all but but the starter/ignition electrics, then turn back on in 'on' position.

is the click from the starter? or a relay? or ?

wallra

sounds like you have a bad connection or a bad ground. the starter draw could be to much also this is why the battery charger on boost helps it start. need to check starter draw.

cobalt

New development. I am assuming it is the switch.

I went to put the car outside and the only way I can do it is to jump it. Unfortunately it is getting less cooperative and this time after a few cranks I turned the key to off and the starter continued to crank. It disengaged the flywheel after a few cranks and went into free spin mode. So I am assuming it is not the starter since I can hear it spin freely. I disconnected and reconnected the battery and everything went back to doing what it did before.

I have a replacement switch but no interest in swapping it out. It is a royal PITA job from what I can see. Most likely the contacts are toast in the switch but I won't know that until I can access it.

wallra

sounds like the starter solenoid is staying stuck engaged. a really easy test is to go to the starter relay and jump terminal 30-87 this will bypass the ignition switch and see If the car starts. I would put the car up on my lift and put a wire on the starter solenoid and touch the big battery terminal this bypass's the whole car wiring and see what the starter does.

Rocket Rob

Sounds to me like you have a faulty starter if its sticking on. I would try isolating the ignition switch from the starter by disconnecting the starter signal wire. Then using a heavy jumper wire (or screwdriver), jump power from the starter to the solenoid. If it doesn't crank normally, then you have a faulty starter or solenoid. If it does then I would suspect ignition switch or wiring.

crg53

^^^^^^
What he said.

Rocket Rob

One other thing to check is do you have battery voltage at the starter signal wire when the key is engaged?

jcs_911

I had a very, very similar problem perhaps 4-5 years ago (on a 1990 964 C2). I was at the track, and came off the track and shut the car off and the fan was still being turned over as if the starter was still turning over. It was weird. It then stopped, somehow. The key was not in the ignition. I drove the car home at the end of the day and everything seemed normal. A day or 2 later, I went into the garage to find the car had moved forward under it's own power, and pushed some tires and stuff into the workbench - in the middle of the night! As was normal for me then, I left the parking brake off and the car in first gear (a track thing). I contacted a few well known Porsche techs in the DFW area and they had no idea as to the exact cause; just things to look at (starter and switch). On my investigation, I found the starter burned out. I decided to replace the starter AND the ignition switch just to be sure. And got a new battery since the old one was worn out. That solved the problem and I have never had a repeat of this.

So your battery going weak may in fact be the starter engaging randomly and wearing out the battery. Maybe? My advice would be to replace both like I did. They are both do-able at home, and just take some time to get them done.

cobalt

Well I haven't had to work under a dash in a long time. I forgot how much I hate working upside down like that!!!!!!!!

Removed the seat pulled the VDO box and the plug the at the end of the ignition switch. Installed the new switch used a screwdriver to give it a try and bam it started without any hesitation. Clearly the switch was the culprit. Now removing the old switch and replacing it with the new one was a job by itself. I would have taken pictures but it was hard enough for me to fit under there as it was.

I guess it is better then the G series cars that you could easily pull the plug and install a switch ala Charlie Sheen and No Mans Land.

ocfservice

Check connection at battery... Probably a loose cable.
Welcome

cobalt

That was one of the first things I did. As I noted above it was the ignition switch which had gone bad. I have seen them go bad before but this was the first time i have seen it go bad so dramatically. Car runs like a champ now.

perlfather

Did you follow any write-up on what needs to be removed to change the switch? I assume this is the part on the other side of where the ignition key is inserted.
This seems to go bad periodically with our cars.
I am also experiencing intermittent failure of starting when turning the switch. Battery cables and contacts have been checked and ruled out as potential culprits.
Even if no pictures are available any words of advice would be greatly appreciated. Thanks in advance.

budge96

Anthony I'm supposing you changed the rear electrical portion of the
ignition , not the entire mechanical key side as well ?

While doing some finishing touches on a recent project decided to
do some electrical clean up under the dash and went to remove the
harness plug and viola entire electrical side slid out in my hand with
various springs, connectors etc...haha was not a happy camper!
Learned very quickly hey it's an awesome design that comes in two distinct pieces for just that reason...Bert

cobalt

It is pretty straight forward. I am not small by any means and getting to it was a royal PITA. One of those easy jobs made difficult due to access. You will need to remove the driver's seat unless you are 3'4" tall. No way around it. First you need to get on your back and get your head under the dash. I highly recommend placing down some cardboard and moving blankets to keep the electronics from digging into your back and protecting them.

Their is a VDO box that needs to be removed. IIRC it was a 10mm plastic nut either side and easy enough to remove. I would remove the entire unit make sure you properly use the locking bars to remove the plugs and don't just yank on them. Then you can see the back side of the switch. Pull the plug. Wiggling it usually works. This gives you access (LOL) to the electrical part of the switch. There are two philips head screws that hold it in place. Just remove these and the unit comes off. Sounds easier than it is and by this point you are stressed and uncomfortable. Installation is just the reverse.

Like i said it is an easy job just accessing it is the issue. I have some pics I took I will post later from a different PC.

Bert,

That must have been fun. I happened to have a switch in stock. The full mechanism is ridiculously expensive. Thankfully they took this into consideration when designing it. I have to do this on my track car this week. Waiting for the new switch to arrive. $108 is not bad considering you add a 0 to the entire units price. It was nice to be able to access it and check to see if it worked prior to replacing it. The one on my track car does not re engage the electro-hydraulic brake booster when you release the key after starting the car. I found this out at the glen doing 140 down the NASCAR straight into turn 10. Makes you appreciate the invention of boosted brakes. That is one down side of the hydraulic booster. You can lose the boost but it takes 4-6 hard braking turns before you realize that your foot better be strong enough to slow you down.