Shark2626

It may be the starter, but it may not as well. So to be certain before buying the replacement I would think that the next step is to pull the starter and have it bench tested at your favorite auto parts store.

spchoiniere

The auto store suggested this too, but I feel like if I'm gonna take the time/effort to remove the starter anyways (I heard the top bolt is a pain) then I might as well replace with something fresh and new so that I can have ease of mind for maybe a few years maybe. If the starter turns out to be good that I take off, well, I guess I would have a spare for when that day comes again.

However, if it is 'not' the starter...then well, that opens up a new avenue of possibilities of the cause for the no start problem.

islaTurbine

Since you have a ‘78, you could consider removing the lower bell housing in order to remove the starter. That’s what I’ve done a few times.

Rob Edwards

FWIW, this gearwrench 8mm ball end socket happens to be the perfect length for the upper starter bolt, coupled with a long handle 3/8" drive ratchet.

Shark2626

Up to you, but you might want to do a couple more diagnostic steps since its not an urgent issue.

See "Step 2 – Check starter and solenoid":

https://rennlist.com/how-tos/a/porsc...r-start-383833

See Post #7:

https://rennlist.com/forums/928-foru...e-run-etc.html

Petza914

This is the one I have installed - https://928motorsports.com/parts/starter.php

You might even recognize the pic I posted of my car on their website, but no affiliation other than a happy & satisfied customer

dr bob

There are a couple more very basic tests to consider. First and easiest is to watch gauge voltage reading while you crank. Does it drop much below 9 or 10 volts? If so, your battery cable connections at both ends need some attention. The single click when trying to crank clues us that the connections may be OK, but the gauge test is simple.

There's also a very basic housekeeping step, and that is to thoroughly clean the battery terminal posts and the cable clamps at the battery. While you have those terminals apart, disassemble and clean the connections at the starter solenoid too. Bright, shiny metal is your goal. Do the ground strap too at both ends. A battery terminal brush makes the terminal and clamp cleaning pretty fast and easy. Gloves and glasses while doing this, by the way.

Since you get the solenoid click but no cranking, you can test the solenoid electrical performance pretty easily. Set your trusty DMM to read DC volts, on the 20V range. Connect the two leads to the large terminal bolts (not the cable lugs) on the solenoid with clamp test leads, One of those bolts has the battery cable connected, the other has a short cable passes into the starter motor housing. You should see battery voltage on your meter. When the solenoid engages correctly, those two terminals are connected by a copper disk inside the housing, and the reading on your DMM should drop to zero. If the voltage doesn't go to zero, the solenoid is the culprit. If voltage does go to zero, almost undoubtedly the starter. You can confirm that by moving one of the meter leads, so you end up with one on the post for the motor-side cable and the other to chassis ground. You should read zero volts at rest, and a large portion of battery voltage while trying to crank. Move the solenoid test lead to the post for the battery cable, and try cranking again. Voltage should stay at a large percentage of battery voltage while testing. If yes and no crank, it's the starter. If it drops low and still no cranking, double-check the battery cable connection.


928 Starters are pretty robust, but do eventually wear out. Some have disassembled and cleaned them inside (lots of dirt and carbon scattered, plus whatever fluids have leaked down there), replacing bushings, turning and often rebuilding the commutator strips on the armature, undercutting the mica insulation between the strips. Replace the bushings and brushes. The winding integrity is tested with a magnet tool colloquially referred to as a "growler" after testing with a DMM for shorts and opens in each section. The solenoids aren't inherently rebuildable without some serious work. A good rebuilder just replaces the solenoid.

928 International uses a good local rebuilder. No worries about their work being top notch. I'm sure that other vendors have similar arrangements with good local rebuilders too. Pete mentions the hi-torque IMI starter, correct one available from our trusted vendors. the clocking on the housings and the terminal setup is critical, so shop carefully if you go looking for these in the wild. Search here will bring up more than a few threads about getting the correct combinations from IMI.

spchoiniere

Everyone seems to like pictures in this forum (as do I) so to help myself and you guys a little here are some...

It definitely looks grimy enough in that area to restrict stuff from working correctly...
So if I understand you correctly...
I should connect the DMM from the bolt with battery cable on it (the red arrow in my pic i believe?) to the one right next to the starter (purple arrow in my pic?)
-I should see voltage with the key in the 'on' position and then when someone starts it, it should read zero? is this correct?
if it goes to zero when starting = bad starter, if it doesn't = bad solenoid




thanks for your help and your patience!

spchoiniere

After looking up there again, I was curious why just a normal L shaped allen wrench wouldn't work okay? Or am I missing something crucial here...? Are those the only two bolts to remove when replacing the starter? And is there any gaskets or anything I need in between? Thanks!

Rob Edwards

A normal L-shaped Allen wrench will work just fine, assuming that the normally-torqued-to-29-ft-lbs cap screws have not been overtorqued, galvanically corroded to the bellhousing, or otherwise been rounded out. The hassle is usually getting enough force to crack them loose in the limited space, though it's easier on the early cars (and automatics) than on the 85+ 5-speeds with the clutch hardline that can get in the way a bit.

EDIT: the starter is just 'short' enough that you can unbolt it and drop it out without having to undo the wiring (DISCONNECT THE BATTERY GROUND 1st....) but it may feel like the wiring harness and/or swaybar will not allow you to do that. It should be wiggle-able out of there.

gazfish

The terminals look pretty corroded, maybe try removing those and cleaning them up as a step along the way before removing the starter?

Shark2626

Below are easy tests recommended to examine the starter circuit system:

Relay? Is your car an Automatic? If so locate the fuse panel and swap the horn relay with the starter relay. These relays are interchangeable as they are the same part numbers. If the engine cranks with the horn relay in place of the starter relay, the starter relay should be replaced. Manual '78 cars do not have a relay, they use a bridge.

Ignition switch? While turning the key to the "START" position, lift upwards on the key. If this allows the engine to crank, the problem is a worn out ignition switch which should be replaced.

Fault in the wiring or is it the starter/solenoid? If the starter will still not operate, slide under the car and use a remote starter switch or jumper wire to supply 12 volts to the starter solenoid by connecting one lead to the large red battery cable and the other to the small lead of the solenoid. Make sure the transmission is in neutral or park before attempting! If the starter engages and cranks the engine, faulty wiring to the starter is likely the cause. If the engine does not crank, the starter solenoid is the culprit and should be replaced.

dr bob

Sorry -- got distracted by a few meetings that seem to be the new CV-modern time-sink.

Test between the posts in the solenoid, the red and purple arrows in your picture. DMM set to read DC volts. You should see battery voltage on the meter right away, and that should drop to virtually zero when you try to crank. If it doesn't, your solenoid is suspect, as energizing the solenoid should connect those two terminals. If it does yet no actual cranking, move the meter leads to the purple-arrowed post and to chassis ground. Should read zero VDC, until you try to crank when it should show close to battery voltage. If it does, the starter is likely bad. Move the test leads to red-arrowed post and chassis ground, and test one more time. Should show battery voltage immediately, and stay close to battery voltage when you try to crank. If yes, definitely it's the starter. If the voltage drops a lot, look hard at the battery cable connections at both ends.

Do This First:
The pictures show terminal connections that desperately need cleaning regardless. Lift the battery ground strap so you can safely disconnect and clean ALL the connections on the solenoid. Bright and Shiny on the lugs, nuts and the terminal bolts. At the other end of the battery cable, make sure the terminals and the clamps are clean (bright shiny) on both the positive and the ground clamps, plus clean the chassis end of the battery ground strap and the pad on the bulkhead there where the ground connects. Bolts/nuts must be snug on all those connection points.

The ground straps are notorious for intermittent failures, usually corrosion that grows like a cancer in the braids that are hidden by some shrink sleeve. Stan (Mrmerlin) had you use a regular jumper cable to bypass the ground strap, clamping one end of one cable (black...) to the battery ground post clamp and the other end of the same cable to a known-good ground point, a mounting nut (not the nut on the center rod), and test again. The jumper cable bypasses the current flow path around that cable if it's weak. Our better vendors have a 2ga tinned marine-grade strap available with new sleeve, a step up from what Porsche supplied in both capacity and durability. Do it if yours is original.

Mrmerlin

NOTE on info from post 15, touching the #14 pin to the hot post bypassed all of the starter wiring, relays if it has one, and the ignition switch tests .
In other words these are not the problem.

but the ground connection could still be a culprit.
as well as what Dr Bob is suggesting to verify the cleanliness of the positive/ negative battery terminal connections

OP based on this picture the engine ground wire is also suspect remove it and clean the areas where its mounted on the right side of the block to the chassis

spchoiniere

So to update!
She started! I took some time to clean up all the connections leading to the solenoid and made them as shiny as i could. Then while i was under there i gave the starter a few taps with a wrench for good luck.
and then, miraculously she started!

I have already ordered a starter, so i might as well replace it while I'm in the mood and plus, there is no guarantee that it couldn't benefit from a new one.
But i took Harlot (the name i gave her) for a celebratory joy ride around town to ensure any battery power lost was recovered and to give me some joy before going to work.

I will update again after I get the new starter in to let you know if it seems to make any difference or not. Thank you guys for all your help! yet again!