Help with starter problem

Oldspiker · 03-30-2005, 02:19 PM

Hi-

My car is a '76 911S that has been sitting in the garage since I got it in January. A few days ago I started it up and took it around the block and then while I was sitting in the driveway inadvertently (obviously, stupidly) momentarily turned the key in the start direction with the engine running. I then turned the engine off.

Since that time when I turn the key to the start position, there is no activity at the starter motor. I thought I'd ruined the starter so I removed it. When I took it to a shop they bench tested it and it worked just fine. I've reinstalled the starter.

I don't believe any current is getting to the starter. When I turn the key there is a click (a relay engaging?) and then a whirring sound that reminds me of the sound a windshield washer motor makes. This whirring sound continues until I release the key. I'm not sure where it's coming from.

Does anyone have any thoughts or suggestions?

Thanks a lot.

Bob

Jim Sims · 03-30-2005, 02:23 PM

Check the flexible ground strap from the body to the transmission (passenger side).

scottb · 03-30-2005, 02:34 PM

Do these starters have a solenoid? If so, is it possible the solenoid has gone belly-up?

Oldspiker · 03-30-2005, 02:39 PM

The starter does have a solenoid, but it tested out all right a the shop.

randywebb · 03-30-2005, 03:27 PM

The click is from the solenoid moving. The whirr means the starter itself is spinning after the solenoid clicks... I almost wrote engages, but it might not be engaging.

Jims idea is that you are not getting enough current due to corrosion. That is certainly the most likely situtation. After that strap start looking at other links in the chain such as the strap in the front corner of thetrunk, the starter switch, the battery condition, etc.

Oldspiker · 03-30-2005, 04:57 PM

I'm sure that the click and the whirr are not coming from the starter and solenoid. Before I reinstalled the starter, I turned the key to the start position and got the sounds I described coming from the front fuse box area.

I'm pretty certain the click is a relay, but I wasn't able to pinpoint the source of the whirring sound. There is a metal device about 1.5 x 1.0 x.75 in a rectangular bracket in front of and below the fuse box with 4 wires plugged into the bottom of it - one heavy guage red and on heavy guage black - that may be contributing to the sound.

The whole fuse box area and wiring is a mess-things have been hacked up and rerouted (maybe I should post some pictures). I've got work to do there, but until a couple of days ago the starter was working.

Bob

911pcars · 03-30-2005, 05:09 PM

Can you connect a voltmeter to the battery posts? During cranking, the voltage should drop from 12+ down to about 9+ volts. If the drop is below 9, the starter usually doesn't crank - check the battery state of charge (i.e. discharged or faulty battery).

Let us know.

Sherwood

Oldspiker · 03-30-2005, 06:36 PM

There is virtually no voltage drop when the key is turned to the cranking position – just the whirr and a drop from 11.9 to 11.7.

randywebb · 03-30-2005, 08:52 PM

OK that kind of a click.... The soenoid will make a bigger click...

So there is no click from the rear ---> almost certain that the solenoid is not moving. Likely due to resistance. So do the gnd strap first and report back. You may just want to get a new one. Be sure to clean up both areas where it mounts - you can use a dielectric grease on all contact surfaces.

The votage drop test is not real reliable - the problem is how much current can flow -- remember you can a nice voltage with current flow of micro-amps, but you can't move chunks of metal around with that much current.

911pcars · 03-30-2005, 11:34 PM

First of all, the battery should be fully charged. 11.9 is not. However, I don't think that's the crux of the problem.

The solenoid doesn't sound like it's energizing. A half-charged battery shouldn't have any problem energizing the solenoid. You should hear it click. However, getting the starter motor to rotate the engine is another matter.

"The voltage drop test is not real reliable - the problem is how much current can flow"

Current flow is a function of voltage and normal current flow during cranking lowers the available voltage. If the battery voltage drops only .2 volt, the starter motor isn't seeing any voltage and current flow is nil.

The following assumes the starter motor assembly was successfully bench-tested.

I suggest jacking up the RR and remove the tire. Check the connections on the solenoid and make sure they're on. I forget the correct color code but you can check with a voltmeter which wire is for the "crank" signal from the ignition switch (source voltage only available during cranking). You might discover:

a) the wire connector was not connected
b) the source wire or connector from the switch to energize the solenoid is faulty
c) the ignition switch is not connecting source voltage from battery to the solenoid wire
d) you may have switched the small wires on the solenoid.

Hope this helps,
Sherwood

Oldspiker · 03-31-2005, 04:07 AM

I will check the grounding strap later today, but my guess is that the problem is either:

"b) the source wire or connector from the switch to energize the solenoid is faulty
c) the ignition switch is not connecting source voltage from battery to the solenoid wire"

probably c).

My starter has only three wires attached to it, the two heavy guage wires from the battery and generator, and a smaller guage yellow wire which must be the connection that activates the solenoid. I was wondering if I were to jumper from the battery terminal on the starter to the this soleniod terminal, then if the starter turned it wold isolate the problem to the circuit between the switch and solenoid. Aside from grounding the battery, does anyone see any danger in this test?

rcecale · rcecale's Garage

There is some great starter troubleshooting advice in this thread. Collectively, the guys here on PPBBS know everything!!!

Randy

Gunter · Gunter's Garage

Oldspiker: Good way to go; get a 12V connection from the battery to the solenoid. (Small faston spade, remove yellow wire)) It should click (Engage) Be prepared that it will also spin the flywheel (Engine) So, take it out of gear. There will be a small spark when you touch the spade connector. Ensure good ground.
The solenoid is a switch devise that pushes the small starter gear into the flywheel ring gear. Only then will the starter spin to start the engine. It all happens pretty fast. The "thing" in the trunk could be an additional starter relay.

RoninLB · 03-31-2005, 12:11 PM

I use a screwdriver to jump from large starter terminal to solenoid.. make sure it's not in gear.

100-200amp battery draw will definately drop battery voltage significantly as per SL's advise.

911pcars · 03-31-2005, 12:16 PM

Large screwdriver works, but arc welding is a possibility for the careless.

Suggest a remote starter switch. Connect to terminals, then push button from a safe distance while sipping tea.

Sherwood

Wil Ferch · 03-31-2005, 01:03 PM

See here, too...even some embedded posts /pics

Starter solenoid yellow wire connection

Wil

Oldspiker · 03-31-2005, 01:18 PM

Well, the starter passed the jumper test, so I it looks like the problem is in the circuit between the starter switch and the solenoid–the yellow wire.

I don't have a wiring schematic for my car, but is it safe to conclude that the diagram for the 911T that is posted at this (PP) web site is fairly close? If so, it appears that from the solenoid the wiring goes to a 14 terminal "multi-port connector," from there to a "buzzer," then to a 6 terminal "multi-port connector," and from there to the starter switch.

Having just started to work on this car I don't know where any of things are, except for the solenoid, of course. I'm guessing that the starter switch is behind the dashboard, but I have no idea where to look for the connectors and the buzzer.

I am appreciative of all your advice.

Bob

911pcars · 03-31-2005, 01:26 PM

Go directly to the ignition switch. The "start" or "crank" position often wears out. Remove the yellow wire from the existing ignition switch and connect it to
your remote starter switch (and a voltage source) to verify it's the switch and not an open in the wire.

Sherwood

crashmy911 · 03-31-2005, 01:33 PM

make sure you are getting good connections and make sure the ground strap is clean. My car when it doesn't start is usually the ground strap. If your battery isn't good then start there. I thin it should be 12.5 or higher.

Tim Polzin · 03-31-2005, 01:47 PM

Quote:

Originally posted by Oldspiker
I was sitting in the driveway inadvertently (obviously, stupidly) momentarily turned the key in the start direction with the engine running. I then turned the engine off.

Bob:

How hard did you turn the key? You may have sheared off part of the pot metal "key" that drives the electrical part of the switch. If it is original, it may have already been damaged.

If you had a spare electrical switch part of the ignition, you could quickly test it.

Tim