Starter issue

[clearrtc]

Hey folks,

New to the forum/Porsches

I have a 924S and I am having an issue with Starter(s). The car sat for about a year and the DME relay kept the fuel pump engaged and burned that out as well as cooked the battery.

I replaced the relay and battery but the car turned over very lethargically and eventually not at all. I got a replacement starter and it cranked the car of well, and I took for a drive mid September, where it had an issue losing power battery light on full etc. So I took it home and turned the car off to grab my multi meter and went to start it again and I just got whirrrr whirrr, the starter would not engage the flywheel, I thought maybe the battery had gotten low on the short drive and charged it up but still same issue. So I decided my reman was bad. I went to warranty it and the parts vendor in Canada requires you to purchase a new item them return the old. I got another reman and it started the car no problem, but shortly after I saw smoke and got under the car the solenoid was smoking ...

I shut the car off and disco'd the battery. I pulled it and tried putting on the solenoid from the original starter, and the car started no problem, but a few minutes of idle later that solenoid started smoking as well.

So I am guessing the starter is remaining engaged and causing the issue otherwise I am not sure what would cause it.

Anyone have any thoughts on what might be the cause if its not remaining engaged?

TIA

Carl

[wwdwgs]

Time to perform electrical diagnostics. Check out clarks garage first.

[Monkey Wrench]

I watched someone start a car I had sitting , trying to move it, they were too inexperienced to know to LET GO of the key before giving it gas. it blew up the starter gear , and did a bunch of damage to sensors and stuff.

you do not want the starter solenoid to enguage while the car is running.
id put a test lamp on the hot for the relay, unhook the relay so it cant; enguage, find out if the power tot he relay is turnign off, It should when you let go of the key, but from what you said it is sitting there smoking.

when the solenoid energises the contacts move in along wiht the armature moving to enguage, this brings the haavy and high amp contacts into contact to run the starter motor, this is a different circuit. you could put a second test lamp on that heavy circuit so you cna watch its power as it enguages and disenguages. of course the starter should not stick on .

possible the armature is getting mechanically stuck maybe the gear has no backlash, make sure the startetr gear is not bound up by havung no lash. it needs a little for free movement.

if your starter circuit had a bad ground, that circuit might have extra resistance. for example , a bad ground from engine back to the battery.. then youd have the resistance of the starter motor and the resistance of the bad ground, the starter would then share its 12V wiht the voltage drop oif the bad ground, so the starter could run slow because its not seeing 12 volts.

With a test lamp across the starter motor circuit youd see the test bulb glow but at reduced brightness, you can put a meter on it and see what the voltage drop is.

how about take a jumper cable, clamp it to the battery negative, clamp the other end to the body and look for a change.
clamp the cable from negative to the engine , look for a change.
normally the body and engine are well grounded, but if one of those grounds becomes a bad connection you might have weird things happening

duplicating that ground would normally have no efffect at all as they are normally well grounded anyway

if your test lamps show the starter solenoiud powered up when it should nto or power from the solenoid through the starter powered up when it shoudl not then you need to find ou the reason for your circuit being energised when it should not be.

the reason I say use teast lamps is then you can leave them connected throughout your troubleshooting sequence and see if those circits are energiesed in real time. easier to watch if a lamp is on than to go read a meter display.

when the starter solenoid pulls in the starter armature moves out. maybe if that is mechanically stuck the starter solenoid could stay enguaged because the realy contacts are closed due to a mechanical bind ,, a test lap may show htings liek that.

perhaps you have something miswired? try to retrace your steps and see if you may have made som wire conection error.. it could be a little error was made and got overlooked? any melted wires that may be shorting against each other or to the body?

you have two circuits, one is the key energising the solenoid, the other is the solenoid energising the starter motor. think of them as independednt circuits, although there is a mechanical link. they are not electrically combined.

everything electrical in the car depends upon a connection through the engine and or and or frame back to the battery ground terminal so good grounds are very important. you will never cause an issue by duplicating or cleaning your battery to body ground or body to engine ground.

the coil in the starter solenoid is meant to be used intermitently , momentarily , not conmstantly. if it sees constant power it may overheat. a test lamp across that circuit should show it being released and power not being held on. and you can watch that it operates consistently

if something is cooking the solenoid I suspect this is the issue. for some reason it's 12 V is not being released as it should..

could the key switch be sticking on? maybe it has bad and burned contacts that are sparking and as a result, welding themselves closed.. ? maybe you can sub in a button for the key switch and eliminate the key contacts fron the circuit temporarily. just for troubleshooting purposes. (the pair that power the solenoid when the key is turned fully)

- again careful. be very aware that enguaging the starter with the engine running can cause some damage.
automatics have a switch so you cant enguage the starter in any gear other than neutral or drive. some cars have a circuit through a brake switch so they wont start unless you have foot on the brake pedal.

most are smart enough not to turn the key fully when an engine is running, hook up a button instead and it may happen accidentally, more easily.

[wwdwgs]

As for the ign. switches - they are fragile. If I'm not mistaken and my memory still works, they are very similar to those of VW's and 914's. And the old ones are also brittle.
OP, while you're tracing the wiring, check out the ign. switch. These switches are not that expensive. If, upon inspection of the switch, you'll see any gray or dark "cavities" inside the switch (the housing is mostly white), know it's time to get a new one. They cost from $12 (OEM) to over $80 (Porsche).
Also, When I replace my starter, I had to mark each wire, as two of them looked similar to each other.
Have fun. It's Porsche - you can fix it.
EDIT, Even Beck/Arnley makes one and available locally.

[Monkey Wrench]

this procedure is for one of the round dash turbo models but likely its quite similar..?
https://www.pelicanparts.com/techarticles/Porsche_944_Turbo/116-ELEC-Ignition_Switch_Replacement/116-ELEC-Ignition_Switch_Replacement.htm

there might be a similar page for your model..



basically its just a switch held on by 2 screws, so I think if you just remove it you can inspect or test with a meter, maybe apply a load. do not confuse the key lock with the electrical switch.

You may prefer OEM, or perhaps find a more affordable aftermarket option. perhaps you can clean it with "deoxit spray" for a temporary period, so the car can run, while you wait for the switch to arrive? it might not be worth cleaning it if it later presents the seme issue. if you are braveenough you might be able to disassemble it and clean the contacts bit Id still only do that as a temorary measure..

sometimes thigns are riveted and Ill drill out the rivets and replace with small screws and nuts. sometimes its just a matter of carefully unclipping stuff.. ocasionally I'll drill a tiny hole to apply cleaners or let them run out on similar swithces.

Im not sure how its held together. If you open it Id do it in a bin so parts don't go flying off and get lost.

Sometimes an owner just need to get to work for a few days while his parts are being shipped or to continue a journey. Other times he can afford the time to just let it sit and wait for a replacement. I don't think its really "worth fixing"

it is likely new contacts have a silver plating or similar for longevity so if you clean or file it, you may make it work but also reduce the life expectance of the now functional but not perfect, filed contacts.

you might find that if you check it woth a meter its bad, then spray cleaners in and restore functionality , perhaps temporarily.