1979 Porsche 924 crank/ no start

[Bryan B]

Hello, my name is Bryan. I have been looking at all the forums that relate to my concern but i still can’t seem to figure it out. I’ve only ever worked on Japanese vehicles so it took me a bit to understand how the 924 works. I’d appreciate anyone who takes the time to help.
I’ll do my best to explain in detail. Sorry if it gets long.

I verified fuel pump operation directly and when it receives voltage when cranking. It might be me doing something wrong but sometimes it won’t power when cranking.
I verified three of the injectors are spraying a nice mist. One not firing at all, but i’d assume it would still start with three injectors?
I’ve also verified spark at the plug when grounded, i have no other way to test the plug.
Also firing order was incorrect but i fixed that, 1342, clockwise on distributer but no avail. Checked distributer rotor was on cylinder 1 when i timed the crank pulley to the notch, but not tdc, i hope it is. Ignition coil primary was 1.7 ohms which is slightly out of spec, is that enough to cause no start? Secondary was at about 8.3kohms which is also slightly out of spec. We got a new coil that supposedly worked with the 924, of course its autozone 🤷*♂️.
The specs are no where close to what they should be but still has spark when i tested it.
Distributor rotor is also out of spec at about .4 ohms but theres no burn marks at the points or the cap. I do kind of see the windings under the dust cover and theres a spot that might look burned but its difficult to see/tell.
I’ve also tried starting it with starter fluid but that doesn’t want to do anything. I’m not sure if that would start a Porsche, European cars seem difficult to me. So i’ve verified fuel, spark. No compression test but this vehicle was running beautifully before and this is where things get iffy, my friend states problems started to arise after a drainage dip on the road, it didn’t bottom out but ever since he said he started hearing a tapping noise in the engine, i was never able to hear it. I told him to change oil and check for metal debris. He said there was none. So he changed the oil and started it, noise was still there, and slowly the car would not start the same way, some days it’ll take a while to start until one day and stopped starting. Cranks sound healthy but maybe a little too slow. We make sure to have a charged battery each time but still no start. And this is where i would like to ask for opinions on things. Whether i should confirm again or maybe something i’ve been missing. This is a friends car that i really want to help get running. Any help is appreciated and i hope you enjoy your day.

[944 Ecology]

You need three things to have a running engine (European or Asian, they all need these three things), compression, fuel in the cylinder, ignition at the right time.

Start by checking the compression. Should be at least 100 to 120 psi on all four cylinders.

If you have compression, then check for spark at the right time. You will need a timing light. If you don't know the timing marks, set the initial timing to TDC on compression stroke.

If you have spark and compression, then check for fuel. Using starting fluid will verify that the compression and spark are viable, if not exact. If it runs on starting fluid, and won't run off the fuel pump, suspect bad gas.


Good luck, I used to have several CIS cars, but got rid of all of them. Motronic is much, much better.

[Bryan B]

Originally Posted by 944 Ecology

You need three things to have a running engine (European or Asian, they all need these three things), compression, fuel in the cylinder, ignition at the right time.

Start by checking the compression. Should be at least 100 to 120 psi on all four cylinders.

If you have compression, then check for spark at the right time. You will need a timing light. If you don't know the timing marks, set the initial timing to TDC on compression stroke.

If you have spark and compression, then check for fuel. Using starting fluid will verify that the compression and spark are viable, if not exact. If it runs on starting fluid, and won't run off the fuel pump, suspect bad gas.


Good luck, I used to have several CIS cars, but got rid of all of them. Motronic is much, much better.

CIS seems to be complicated for no reason lol
But its interesting. I’ll have to check compression so i have no doubts. Also i’ll check with a timing light to ensure proper order. I’ll see what happens from there.

[wwdwgs]

fuel pump relay?
My car (1987) stopped running a couple of years ago. I thought it was computer, but replaced fuel pump relay with a new one and the car came back to life.
I opened old relay, and looked closely under a magnifying glass - yes there were cracks on soldering points, which caused this problem. Otherwise, old relay looked very clean inside.
I don't know if yours (1979) has the same fuel pump relay.
Are the electrical connections clean?

[Bryan B]

Originally Posted by wwdwgs

fuel pump relay?
My car (1987) stopped running a couple of years ago. I thought it was computer, but replaced fuel pump relay with a new one and the car came back to life.
I opened old relay, and looked closely under a magnifying glass - yes there were cracks on soldering points, which caused this problem. Otherwise, old relay looked very clean inside.
I don't know if yours (1979) has the same fuel pump relay.
Are the electrical connections clean?

Sadly we replaced the relay and it didn’t fix it, i confirmed the fuel pump runs when cranking the engine. Grounds has a bit of resistance at about 1 ohm so i for sure need to clean all the grounds under the dash.