86 Carrera Starting Problem

[kbruz]

Got stranded tonight in my 86 carrera. I stopped on my way home from work for dinner and could not get the car to restart. It took about 2 hours to get the car to work.

All of the power works, lights, stereo, horn, etc. The lights on the dash went on when I tried to crank the car, but nothing happened. Never had such a problem before. I'm thinking that it may be one of the following

1. DME relay underseat. Although I thought that once this failed, car would not recover?

2. Starter ground strap

3. Starter solinoid

4. Starter

THouguhts? I found a simliar thread and John Walker recommended the starter due to thermal issues with connectivity.

[kqw]

+1 on the probability of a starter issue.

Usually when a DME fails, your car will crank but not start.

When you have a DME failure, replacing it is simple and you are off and running again.

[rnln]

Many people here experienced different things and according to common sense, there are many things to look at. Base on my personal experience, I tried to repair/replace more than 1 thing and the problem was still there once in a while.
So far, my starter is replaced. The wire which suplied voltage to the starter solenoid always have enough voltage under the dash. I wanted to measure the voltage from this wire right at the starter but I had to wait over a year to have a chance since every time the car is lifted/jacked in the air, it started fine.

Lately, a month ago, I had a chance to get the car up in the air while the problem is still there. Measuring this wire right at the starter and found that it only has around 7v if I remember correctly. Got up and measure the same wire at under the dash, it carried almost 12v. I then extended the wire enough to get a 12v source in the engine bay. Before giving this wire 12v to start the car, I try to start the car by the key again to make sure the problem is still there. Soon I gave the extended wire (lead to the starter) a 12v, the car start right away. Problem solved.
As you can see, in my case, my problem is the wire which comes from the key to the starter solenoid. Sometimes, it carry enough voltage to the starter, somtimes it doesn't.

[Robert Buchanan]

kbruz,

The DME relay can exhibit an intermittent functional condition. I have had this happen when a 964 simply shut off at eighty MPH. After a tow home it started and ran fine....for fifteen minutes. The original relay had 98K on it.

My 3.2 had a "long start" cycle and I changed out the original (24 YO) forget the miles....and it cured the small issue.

Try a new (not borowed) relay. At $22 bucks it's a worthwhile investment to have a spare in the glovebox.

911_pilot

[3.2 CAB]

kbruz, I believe the problem is with the yellow wire that is in the ignition circuit. I believe that I have posted here before about this problem. After a car gets driven, it sometimes will take more current to actuate the solenoid, due to heat expansion and such. Mine got to a point that I always parked where I could roll off to start, if my starter was on the blink. When I was first trying to trace the problem down, just about everyone was saying "your starter is bad" I pulled my starter and started to examine it. I removed the solenoid from the housing to inspect the internal contacts, you could see a little carbon like smut, around the contacts. I cleaned the contacts, and reassembled the solenoid(involves soldering) I thought I fixed it...Wrong!! It still did the same thing after an hour or so drive. I had already checked the voltage at the starter, and it was all within range, but then I found that when you actually tried to start the engine, the voltage/current dropped way low on the yellow ignition wire. It would show 12+volts, but it would not carry enough voltage when the engine was hot. I replaced the entire length of the yellow wire, and I have had no further problems like that again. It seems that over the years, the yellow wire tends to breakdown and be prone to failure, and by replacing it, has solved a lot of no-start problems. Good luck!!

[kbruz]

THanks for all of the information. You state that you changed the entire length of yellow wire. Where does it go? From the ignition key to the starter?

[84_Carrera]

Hehehehe, recently had this condition with my '84. Changed electrical side of the ignition switch - not the problem. Cleaned the contacts at the 14 pin connector in the engine bay - not the problem. Replaced the starter - not the problem. Checked the grounds at the trans & battery. Wasn't the battery either. Stumbled across the problem at the mechanical side of the ignition switch, as we were doing meter tests of the wiring.

In my case, with the electrical part of the switch connected to the wiring harness but NOT attached to the mechanical key lock (hanging down under the dash), the car starts 100%. I believe in my case there's something mechanically binding the key to prevent rotation enough to engage the electrical part of the ignition switch.

There's a LOT of stuff it CAN be.

I believe the yellow wire he's referring to goes through the tunnel, if so, that's some work from what I understand.

Good luck!

[stlrj]

Solana Beach, CA?

Bet it was raining like here in Novato CA and now you have moisture inside your distributor cap.

Cheers,

Joe
74 911 w/86 3.2

[3.2 CAB]

Hi kbruz, yes I did replace the entire length, except the little bit between the ignition switch and the dash bulkhead, where the plug-in connector is located. It can be seen in the trunk if you get to digging around in there. This is also the same wire that most aftermarket alarms get spliced into for the ignition kill. That could also be a possibility of a fault, if there was an aftermarket alarm ever installed in your car. It could still be in the "ignition loop" or circuit and causing a problem. Also, the dash bulkhead connection, is sometime the cause of a no-crank problem, and it just needs cleaning of the contacts and firmly re-connected. Hope some of this helps. Good luck!! Tony.

[stlrj]

Hi Kbruz,

After reading your post more carefully I have come to the conclusion that your starter solenoid is bad and it has nothing to do with the rain.

Cheers,

Joe

[kbruz]

All thanks for the feedback. I will investigate this weekend. Last question. Can the solenoid be replaced separately from the start?

[stlrj]

Yes, that's how I fixed my 86, but then you need to find a solenoid sold separately.