Starter continues to run
 

EDIT: Spoiler alert!! Bad fuel pump relay was the problem.


Car starts up as soon as I turn the key to run and won't turn off unless I turn the car off. Already threw some money at it in the form of a new electrical portion of the ignition switch.

Did a search and found something that sounded similar and it was suggested that it was a sticking solenoid.

Few questions: first, does this seem like a solenoid issue and if so, can I get either a replacement solenoid, or do I need to purchase either a new or rebuilt starter?

Thanks

Sticking selenoid or eletrical part of ingition swicth.

Put in a new electrical portion today and nothing changed. I don't see a solenoid for sale here on Pelican; there are several on eBay that aren't very expensive- $40

Any thoughts?

Before you shell out for a new solenoid, I would remove the solenoid and see that the mechanical yoke that pushes the gear back and forth works freely and that the return spring isn't broken. Either wear or dirt isn't allowing the plunger to return to the off position. Probably just needs some cleaning and bit of lube. A local auto electric shop could probably fix this in a hurry.

have you done anything to the car before this.

so, as soon as you turn the key to ON, it starts and runs. does the starter keep turning?
not sure if the starter is hung on the flywheel it would keep the solenoid pulled in but maybe

Correct.

Bench test........
 

Rutaber,

Remove the starter from the engine and have it bench tested. If you don't know how to test it, bring it to a starter shop. If the starter passed the inspection tests, then you know it is not the starter but other related parts. It could be electrical or mechanical problem that causes this problem. Keep us posted.

Tony

Not a cure but to relate my Rx-7 has done this for a couple years.

I put in a rebuilt starter because of corrosion around the terminal. If the car starts everything is fine and the starter disengages. It started fine for a year or so after the starter install. If the car does not start the starter continues to run until you jump out and disconnect the neg battery cable. This will disengage the starter also and you can immediately hook up the battery.

I took it out and looked at it and as far as I could tell it looked fine.

They wouldn't exchange it and so I have just lived with it.

I will pull the starter in the next couple days and see what it looks like.

I did just do a complete refurb of the CIS on the car. I only did a partial engine drop and didn't touch the starter or wiring to it. I did pull the 14 pin connector and then hooked it back up after bring the engine back up.

The car started right up and I spent several hours adjusting the mixtures; towards the end, a weird sound started and I shut it down and determined it was the starter still running- was able to get it to stop for a while, now it wants to always run when I hit run position on the key.

Thanks for all the responses, I'll keep everyone posted.

Doing more thinking on this and here's why I originally thought it must be the ignition switch: first time I go to start it from off, it starts right as I hit the run position, not to start and back, but as soon as the alt and oil lights come on the dash, the engine starts right up, if I try and back off the switch, even a tiny bit, engine and starter stop.

Rutager

Using the electrical switch/tumbler........
 

Rutager,

Do you know that you could start the engine by using the electrical switch or tumbler of the ignition switch? The ignition switch is comprised of two major sections:
a). The mechanical section which locks the steering wheel and the switch.
b). The electrical switch will all the electrical connections for the ignition switch.

Separate the electrical section from the mechanical section and investigate. Use a screw driver as a key to turn the electrical switch and see if the problem could be replicated. Keep us posted.

Tony

First, follow Tony's advice and remove the electrical portion and separate the electrical portion of the switch, plug it into the harness, and use a screwdriver to turn the electrical portion.

The bold portion of your post, above, is very important. Clearly, the coil inside the solenoid is being powered as soon as the ignition is turned on, and it should not be. The starter motor (not the solenoid) is powered directly by the battery and is not affected by turning on or off the ignition. If the solenoid internal switch was stuck, turning off the ignition would not shut down the starter motor because the motor would still be powered by its direct connection to the battery. Since your starter stopped as soon as you turned off the ignition switch, it tells you it's the solenoid coil that's being affected. Your latest post (above) confirms that you have an electrical fault that sends power to the starter with the ignition switch in the "run" position instead of just the "start" position.

Use a test light, disconnect the yellow wire from the solenoid and connect one lead of your test light to it, and the other lead to ground. Turn on the ignition switch. Does the light come on? If so, you have a wiring issue as the light should come on only with the switch in the "start" position. Your fault may be intermittent so try the test several times.

Bottom line, you've got a switched power feedback into your starting circuit wiring somewhere. A stuck solenoid drive pinion would not shut down the starter when the ignition is switched off. A faulty internal solenoid switch would not shut off the starter when the ignition switch is turned off. Only a solenoid coil that is being powered by a switched power source would activate as soon as the ignition is switched on instead of the "start" position. Whether or not the fault is the electrical part of the switch or some electrical feed somewhere along the length of the yellow wire to the solenoid will have to be found.

did you put the 14 pin connector back on correctly.

Hi guys,

Thanks for more info. I have the ignition switch completely out and did use a screwdriver on the + slot in the electrical portion and the problem still occurred.

I'll double check the 14 pin connector, although I would think that there would be lots of other problems if it was off a pin or two!

I'll do the tests on the wires tonight and post results.

Rutager

Okay,

Did some more testing- pulled the yellow off the solenoid and tried to start- engine didn't turn over, but I could hear the fuel squeal. Pulled the red pump relay and no squeal.

Put the electrical tester on the yellow wire and ground and got twelve volts in the run position.

Judging by the pump running and the starter running before the ignition is in start, what are your opinions?

I just got a new Porsche electrical ignition part from Pelican this week and tried that one and my old one- same result. Possible new one is bad too?

Thanks,
Rutager

I Your test confirms there is a fault in the start circuit. Pending the clarification of your tests, the most likely area is your new switch, IMO. I don't have access to a diagram of the switch wiring, but someone will post it, I'm sure. With the diagram and a continuity tester, you can check to see if you get continuity between any of the power terminals of the switch and the terminal for the starter (50, I think) when the switch is in the run position. You should get continuity between power and the starter terminal only when the switch to turned beyond the spring loaded start position.

L.J.,

Correct, the pump started running at the run position, not the start position

Bob K. had very nicely emailed me the wiring diagram for my '77, looks like a good time to print it out and start seeing what flows where.

Rutager

I added some things to my post, please take a moment and reread it as there are some other questions.

Here's a link that may help.
http://forums.pelicanparts.com/porsche-911-technical-forum/430286-problem-ignition-switch-wires.html

L.J.,

Yes, I believe that I was hearing the injectors squealing- didn't want to do it for long as I didn't want to flood the engine. Noise was coming from engine compartment.

When I rebuilt the CIS, I turned the 3mm screw back several turns then had all the injectors in jars and turned the screw until they just stopped then backed it off a half turn- this was how I read the factory manual. During my tuning, I might have moved it forward a 1/16th of a turn.

What do you mean by off the stop? How do I repair?

Thanks much,
Rutager

I just assumed the mixture screw had not been touched and suspected the plunger in the intake was not fully down and resting on the air flow sensor switch. If the switch is not closed by the plunger, there is no ground to the relay and the pump runs in the on position without the engine running. Additionally, a raised plunger arm causes the injectors to squirt. However, your adjustment of the 3mm screw could account for that. Still, the pump should not run with the engine off and ignition on. Perhaps the wire to the air flow sensor is disconnected.

You may want to try a simple test with your test light. This test is not really a diversion from your original problem and can, in fact, further confirm is the ignition switch is faulty.

Remove the fuel pump relay. Connect the lead of the light to a ground and turn the ignition switch to run position. Touch the probe tip into the following relay sockets and see if you get these results:

Socket 86--light on

87a--light on

87--light off. (This is a branch of the wire from the ignition switch to the starter. If you get a light here, then the wire is being powered when it shouldn't be--probably from the ignition switch.)

Next, reconnect the test light lead to a power source. Put the probe tip into relay socket 85 (the connection to the air flow sensor switch), and the light should go on. If it doesn't light, then either the air flow switch wire is disconnected, the afs switch is bad (not likely), or the plunger is not resting on the switch.

If you decide to run the above tests, please let us know the results.