BS911

I wanted to share my successes, failures, and general pains surrounding what turned out to be a starter replacement.

Last week, my car wouldn't start but some electric motor deep behind the engine was constant running. Because I was too much in shock to fully diagnose WHAT electric motor was running (even without the key in the car) I mistakenly thought my aux air pump was stuck on, leading me to believe there were electrical gremlins - aka: get your wiring harness replaced, bonehead. Instead, it was just the starter. With the battery connected at all... whirrrrr went the starter. No crank... just whir. No key in ignition, just whir. This means my starter HAS to be bad. If it was ok, then a drop on current on the 30A yellow lead would kill the motor. And yes, I isolated the ignition switch, the yellow wire, everything... whirr.

So I ordered a rebuilt Bosch starter, next day air. Swap the starter with the "new" one. No more constant running starter motor... so that's good. Test start the car, click, whirr, electrical popping... oh crap. No crank. In the process of troubleshooting with my handy dandy alldata schematics, I effectively isolated the started from the rest of the car... both upstream and down. click, whirr, pop, clickety... no crank. I have now removed and reinstalled this starter FOUR times in my testing. Did I screw something up? Can't be. Back to rennlist searching. New battery. AH HA! Dammit all if I just am not getting enough juice to keep that sucker engaged.

New Red Top battery goes in to replace my old Autozone battery. I think I have it... click, whirr ... no crank. SON OF A @#$^& !!!! My hands ache like you wouldn't believe as I remove this rebuilt starter for probably the FIFTH time. Now I notice that the "rebuild" included a solid repaint of the case, which as any of you electically knowledgeable folks out there know... serves as a great insulator - verified by my handy dandy ohmeter. So For the 10th time, I have things figured out. I scrape the paint off the bolt section where the ground strap connects and where the starter mates to the engine case. This HAS to do it. Starter gets installed again. Click, pop, clatter, whirrrrrr... no crank. MOTHER, piece of, lousy, filthy, rotten, floor flushing, useless... Every once in about 10 start attempts, it engages the motor for a half revolution, then the starter kicks out to just sit and spin. I even managed to get one or two starts throughout the process, so I know mechanically, everything is ok in the motor. My next leading guess was a failed flywheel that maybe was spinning the starter gear, but nothing else... nah, can't be or it would never start.

Ok, think Brian. You must be an idiot, just figure out HOW. Battery: good. Rest of car: Proven via isolation. I even hot jumped the starter lead and it won't engage the flywheel. So I figure the old starter, possibly complicated by a weak battery, got in a "stuck open mode" and wouldn't disengage. After I removed it I played with it a bit to figure out how it works. I know it is disengaged now. What the heck, maybe I loosened things up, so back in goes the old starter. Make all contacts... vrooooom. Every time.

SO... what I know.

Original starter - got stuck engaged.
Original battery - probably on the low side. Can't prove. New battery anyway is a good thing.
Wiring harness - not the cause of this problem - but ok, I'll get it replaced anyway.
New starter - poor, poor, poor rebuild done probably by a guy who knows nothing about cars or electrical components. I'm sending it back and getting a new, in the box starter to swap with next weekend.

On the plus side. I can honestly say that excluding jacking up and securing the car and disconnecting the battery, I can change a starter in no more than 20 minutes at this point. I can even do it without removing the half shaft. A tight fit, but doable. That top bolt... piece of cake. Just get an extension long enough to reach past the starter motor, reach up and slide it over the top of the starter motor and feel around until you get it engaged. No transmission hugging required. For sanity though I would recommend still removing the half shaft. Right now, my car is ready for a drive tomorrow morning. For the rest of me... that might take some more time.

Hey... anyone need any pointers on how to replace a starter?

Robin 993DX

Brian,

The problems you described sounds suspiciously like the problem I had before I replaced the starter....

After replacing the starter I was still have the same problem, so I replaced the battery, which fixed the problem. Occasionally I still have this whirrr problem, but no engage, but now it only occurs on a hot car that have been sitting for few minutes. will never do this when the car is cold. I still think something is wrong, but I am leaving sleeping dog the way it is. I am happy the car starts everytime when it is cold.

BS911

Hi Robin...

I actually came across a lot of your information in my searching. That is what led me down the new battery route. I honestly don't see how anything else in the wiring or rest of the car could be the culprit - except maybe a faulty ignition switch. Once that 30a lead goes hot and the starter gear engages, the main 50a lead engages and the starter motor pulls straight off the battery. I unplugged my ignition switch harness plug and direct jumped the 30a and 50 leads on the starter with the same problem. I disconnected the hot lead going from the starter back to the main engine harness - same problem. So there was no way anything else had anything to do with it.

I wonder... do you also have a rebuilt starter in your car? Or do I remember in the searches that you have a "junk yard" starter? If it is a rebuild, I'm curious as to how secure the grounding is on that mounting bolt where the starter strap mounts to the starter battery. I was getting very poor ground with all the "rebuild" paint coated all over the thing. With that poor ground, any increase in starter load or resistance would be enough to get that starter gear to kick out. Like a hot engine.

Anyway, after doing all this work, I would very strongly believe that if you still have intermittent problems, it is either the ground connection, or just a weak starter itself.

Pete

Hey Guys,

Haven't even been under my 993 much less looked at or for the starter so this is probably a stupid comment. All of my starter experience is with Harleys and Land Cruisers but some of the problems you describe sound like they could be solenoid problems. The solenoid is just a switch that when engaged powers the starter motor and also engages the starter bendix, the little do-hickey with the gear on the end that pops out and engages the ring gear on the flywheel. If the solenoid is sticking, it could explain why you heard the starter motor continuing to run even after you turned it off. I would think the rebuilt Bosch starter you purchased would have come with a new solenoid, but maybe not. If not, I'd probably take the solenoid apart and clean the contacts in it. I don't know if any of this pertains to Porsche starters....

Pete

BS911

I just wanted to close the loop on this problem.

After getting one bad rebuilt starter and one wrong part starter, I had opted to stick with my original starter, thinking it had worked itself loose again. Well, Last week it finally did it again.

(Turn the key, weird/slow crank like it doesn't want to turn, then kick out to spinning starter motor while not engaging flywheel. Release key, starter continues to run. Had to disconnect battery.)

So I ordered a brand spanking new, Bosch starter for $480 at a discount online dealer. Got the new starter today, did a starter change in about 40 minutes and all is well again. (You do it 6 times and you'll be pretty fast too!) I even intentionally left battery state alone without a charge to make sure all other conditions remained constant. The thing cranks like a whole new beast.

Of course, I can't leave well enough alone and I just HAD to know what was going on there, so I ripped my old starter apart. Everything mechanically looks great in the old starter. The planetary gears, the drive gear, everything looks absolutely perfect. After a mild cleaning and lubing, everything works perfect. The main motor looks good... obviously shows some minor signs of use, but looks good. The solenoid looks perfect on the inside, but can barely pull its own weight to close that piston down. If the piston is nearly bottomed out, energizing the circuit will draw it closed. The farther out from bottom it goes, the slower it responds. All the way down to its normal, at rest position, the solenoid won't even begin to pull the piston in. Additionally, the contact switch under the solenoid base felt sloppy. WIthout a doubt... the solenoid was the problem. So Pete... I think you were absolutely spot on.

This experience however, has taught me once again to NEVER trust anyone else's work. A rebuilt starter... pfffft. I guarantee the rebuild didn't touch the solenoid, so I only got someone else's problem. All they did was clean and lube and repaint the body to look nice... INCLUDING painting the contact points for the ground strap. I once again quote a very, very wise man...

Anyway, I hope this information proves useful for future searchers.