924Board.org

[CorsePerVita]

Ok so I thought for sure I had fixed an important issue that has plagued me now for the last several months. BUT... I was wrong. Here's the symptoms:

- When car is driven to operating temp and turned off, car will sometimes not start. No crank.
- Car CAN be push started.
- When in this condition and key is turned over to "start" you can see the dash lights briefly dim as if it's trying to draw. However, there is zero sound from the starter. Not even a click of a solenoid or the sound of a dead battery.
- Sometimes if the car is started soon after it is turned off, it'll be fine. Inevitably, if it sits for about 10-15 minutes after it's turned off, especially in severe cold weather (say 15F) or even just below freezing (but always below freezing), it will do the same. No crank. Can STILL be push started no problem.
- Sometimes if the car is started soon after it is turned off, it'll be fine, but in severe cold weather it might act like it's engaging intermittently. As if something is loose, or disconnected, then plugged back in, basically weak... weak... CRANK CRANK good.

Now... I thought for sure, "oh man my starter is going out." and realistically it was because sometimes you could hear it spin but not engage the drive, drive was going out, and sometimes the solenoid did stick.

So I replaced the starter.

For 2 days, TOTAL SUCCESS. Then.... suddenly, it did it again yesterday. Then again tonight 2 ft from my driveway (where I've managed to push it up as far as I can get it....).

I've also replaced the ignition switch a while ago, and the same symptoms occur, even though the previous switch was absolutely no good and on its way out.

Some things I've thought:

- Maybe I have a shitty main ground somewhere. But if I do, WHY would it be affecting things ONLY after I drive the car for a while?
- Perhaps there is condensation that has built up somewhere?
- Stefan recommended perhaps a bad relay somewhere? Why would this matter though at specific operating temps? Perhaps it's coincidence, or weather related. Still, I thought perhaps the starter circuit was direct to the starter, though I may be wrong.
- Perhaps there is a relay elsewhere with a bad ground?
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

[morghen]

What happens if you get current from another battery in paralel while this problem is manifesting itself?
I mean hook up your on car connected battery to another car battery, + to + and - to -.
I have the EXACT same problem and with a fresh battery or with help from another battery it cranks normally and starts.

I have also rebuilt the starter, but the solenoid is still the old one...so i fear that the solenoid is half dead and cant handle the heat and cold anymore.


My thougths: 1) battery, 2)starter solenoid, 3) main ground wire-the one on the engine, 4)starter wiring
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Supercharger and EFI kits
https://www.the924.com

[CorsePerVita]

[CorsePerVita]

Ok the strap going to the engine was dirty as hell. I cleaned it up with some electrical cleaner. Looking at the ground strap to the firewall I do see a bit of corrosion. Going to go get a new one tomorrow.
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

[Fasteddie313]

You could test by putting your jumper cables from the engine as block ground to your chassis or straight to the battery ground..
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80 Turbo - Slightly Modified

[ideola]

It might be the problem described here and illustrated in this photo:


Not a problem with the switch, but rather the nose of the ignition cylinder being worn down, which will interrupt ignition in all sorts of crazy ways.
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erstwhile owner of just about every 924 variant ever made

[CorsePerVita]

Alright... so...

- Inspected switch (it's fine), the actual switch itself was replaced, but the tip is fine as well.

- Replaced main grounding strap. Replaced strap from engine to firewall after checking resistance, and resistance was high. Not in great shape.

- Replaced starter last week.

- Replaced battery today after crank test. Crank test showed voltage drop to 2v upon cranking, even after fully charging. Replaced with new battery.

Car now consistently fires, no matter temperature. Also went to larger ground straps since whoever had replaced them last used thinner grounding straps.

I should note that the strap that goes from the intake manifold to the firewall where the ignition coil is i took off and cleaned. I then put that back on and ran a NEW ground strap directly from the intake manifold (same plate), ran it behind through the rubber boot into the battery area directly where the main ground strap goes to the battery to help improve the ground there. As I was tightening the old ground stud, with little to no effort, it snapped right off. I ended up drilling in a new one, ground some fresh metal down and put a new bolt in there. When it warms up I'll weld a new one in, for now it's more than sufficient.

Considering the lack of hesitation and how much more powerful it was turning over, I think the majority of my issues were the bad starter where the drive was intermittently going out, intermittent shitty ground resistance issues (the old main strap resistance was high, no matter where I tested it), along with a battery that was probably slowly dying and not fully charging also probably due to shitty grounding.

On a side note, the other car has sat and sat buried in the snow due to the plow having buried it alive. I unburied it today, hopped in, expecting to not even turn over. It cranked a couple of times and fired right up.

So... now I have 2 out of 3 running 924s. I kinda stole the battery out of the megasquirt car, so it isn't going anywhere till I get a new battery. It wouldn't get far anyway, it'd just suck the snow right up into the itbs lol.
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

[Tiny]

Hey CorsePerVita,

Is it still consistently starting up?

I might need to go over and re-do the grounds and beef up where necessary too.
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*****1981 - 924 - Auto - London, UK******

[CorsePerVita]

[Ian89C4]

So I just had this problem on the race car. Check your ground to your wur. I checked the connector and no continuity to earth. Turned out I had an internal failure of the connector. Replaced it and good as "30+ year old new".

Hope it's something that simple.

Cheers!
_________________
Ian Edgerly
North Carolina

Current:
1981 924 SCCA/ChampCar Weissach Race Car ("Serenity")
1987 924S ChampCar Endurance Car ("Der Weg")
1980 924 Euro ("Wahala")

[CorsePerVita]

[Paul]

Check circuit 30 at the positive battery clamp and at the back of the fuse box (2 red wires).
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.