Test your 944 starter the easy way!
 

At one time or another most Porsche owners will experience the “click-click, no turn” sound from the starter solenoid. Here’s a painless way to diagnose the problem without having to jack-up the car to get to the electrical terminals at the starter.

The very first item on the list is to make sure you have a fully charged battery. If in doubt, let it charge overnight on a slow–charge mode. The battery posts and cable terminals should be cleaned with a wire brush and tighten for a good connection. Also ensure a good connection of the ground wire from the battery to the engine (at the bell housing.)

If the starter does not turn after the above steps then the problem may be caused by a faulty ignition switch or the starter’s solenoid (aka “bendix”), the starter motor itself or a fault somewhere in the wiring.

If you take a look below at the wiring diagram for my ’86 944, you’ll see that there are no relays or fuses between the ignition switch and the starter solenoid. It is a simple connection from the positive terminal at the battery to the ignition switch and then to the starter’s solenoid which, when activated, closes an internal contact passing power to the starter motor. The solenoid also thrusts the starter’s pinion gear forward which engages and turns the flywheel.

So where to begin testing? Well, if we bypass the ignition switch and apply power directly to the starter solenoid we can easily determine if the starter requires further testing. If the starter turns, then it’s safe to assume that the problem is not with the starter but that the ignition switch may be the culprit.

Here’s how Clark’s-Garage suggests the above test be conducted: Checking Starter Operation

Being the lazy type, I didn’t feel like jacking up the car and a closer look at the wiring diagram gave me answer. There is an easily accessible electrical connector that joins the starter wire harness to the harness that goes to the ignition switch. Connecting a jumper wire from the plug of the Red/Black wire at the starter’s harness connector to the positive terminal at the battery will bypass the switch and test the starter’s proper functioning. Easy, right?

Parts:
1. The connection at the harness connector is via a male plug so you’ll need a female terminal. I had a box of butt-end connectors on hand
2. About 3-4 feet of heavy gauge insulated wire (10 or 12 gauge min.)

How-To:
1. Cut about ¼-inch from one end of the butt-connector so it will make good contact with the plug
2. I folded one end of the wire back on itself and hammered it to a smaller diameter so it would fit tightly in the butt-connector. Crimp the connector
3. VERY IMPORTANT: Make doubly sure the car is in NEUTRAL and the handbrake set. The ignition switch should be in OFF position. DO NOT stand in front of the car. Common sense, please.
4. Touch the free end of the wire to the POSITIVE terminal post at the battery. No need to maintain the connection for a long period of time. The starter should crank the engine immediately. If you hear the infamous click and the engine does not turn, then it’s time to remove the starter for further testing. Your local auto parts store will gladly test it for you.
5. Should the starter turn the engine OK, you should check the ignition switch next.
Good luck!!

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This is cool. It would come in handy to run a compression check, too. In the old days they used to sell a remote starter switch you could alligator clip to the Bendix so you could crank the car form under the hood to check compression.

Creative way to test it. Nice job

Not meaning to be nit-picky, I agree that is an elegant solution to testing/running the starter easily from the top but..

Solenoid <> Bendix. The solenoid is the coil assembly on top of the starter and the drive gear assembly at the snout is loosely referred to as a Bendix. In some older vehicles the solenoid may even be mounted on the firewall and not on the starter at all.

IIRC, the 944 starter is actually a different drive engagement design?

The 944 starter is essentially the same as most other starters I've seen and worked on. it just mounts backward and spins the opposite direction. It's exactly like the Chevy starters on the older cars. Ford on the other hand liked to mount the solenoid somewhere else (firewall, fender housing) else, like you mentioned.

Dad made up a button switch with a long wire and alligator clips on either end for easy attachment to the battery and the terminal on the starter for the solenoid. That way when he adjusted the valves on his race car engines, could bump it over with the button while watching the timing indicator on the harmonic balancer. This worked well on any of the race cars that he worked on for himself and others.

You are absolutely correct; the name "Bendix drive" applies to the spiral drive mechanism of an “inertia-type” starter. However, my understanding is that the term "Bendix" is (incorrectly) sometimes used for the entire “pre-engaged” starter mechanism of which the solenoid is a part. My intention was to separate the mechanism from the motor itself. But, again, your nomenclature is correct, i.e. the solenoid is not "the Bendix."

To answer your question... My '86 944 features a "pre-engaged" starter design which simply means that the solenoid moves the gear mechanism forward to engage the flywheel BEFORE closing electrical contacts activating the motor. The type of solenoid that is mounted somewhere off the starter itself is simply a relay that turns the power on to an "inertia" type starter.

From wikipedia.org:

“The main drawback to the Bendix drive is that it relies on a certain amount of "clash" between the teeth of the pinion and the ring gears before they slip into place and mate completely; the teeth of the pinion are already spinning when they come into contact with the static ring gear, and unless they happen to align perfectly at the moment they engage, the pinion teeth will strike the teeth of the ring gear side-to-side rather than face-to-face, and continue to rotate until both align. This increases wear on both sets of teeth. For this reason the Bendix drive has been largely superseded in starter motor design by the pre-engagement system using a solenoid.”

Thanks for your input!

Leo944,

Nice work.

In addition to the Clarks information, a super tech frwilk@the944.com had a similar method.
His entire site is now unuseable.
Great information lost.

I printed a copy a while back and used a "push button starter switch" like they had in the old days.

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Your circuit diagram explains a lot.

J_AZ

Bendix = overrunning clutch in some parts diagrams

The944.com was a good site. It's still available through The Wayback Machine (Internet Archive).

https://web.archive.org/web/20150217023938/http://www.the944.com/index.htm

Thanks tamathumper,

Link works!

https://web.archive.org/web/20150224090304/http://www.the944.com/remote.htm

John

Thanks John_AZ & Tamathumper. Great research. That website looks like a great place to browse.

BTW, John, I was able to fix the lack of oil pressure that haunted me last summer. I replaced the OPRV and, so far, it seems to have resolved the problem.

Leo