Hi everyone! I am completely stumped by my car! Any advice and help is appreciated. Thanks in advance to anyone who takes the time to read this.



I’ve got a 1994 SL320 (R129). She’s only had a radiator issue that I’ve fixed up until recently.



It started with the alarm going off after a few seconds of driving, randomly and only a couple times, maybe once a week for a month.



Then I went into a store and came back to a no crank or start. Luckily I was in a center with auto parts store, they tested the battery, it was fine. They charged it anyway just to be safe. After about an hour, she magically turned on. However, the alarm went off again. I had to turn car off, unlock all the doors to disengage the alarm and then started up again. It ran fine for another day.



Then it happened again, same exact way, including alarm issue. The next morning, she wouldn’t start at all. I tried changing out the battery, no luck.



Since then, I’ve done the following.



Replaced all wires on the engine harness because the wire coverings were biodegradable and had completely deteriorated. Purchasing replacement harness meant it would be the same covering on wires so we did it ourselves instead. Replaced the starter wires as well. This was mechanics first guess as to what caused the car to stop working.



After that didn’t work, I replaced the starter. Still no crank or start at this point,



I changed the fuel pump relay and all back fuses. Finally I got crank! But no start.



Tested spark plugs, no spark. Replaced spark plug wires and ignition coils as well, still no turn over. Messed up here, haven’t retested the spark yet, waiting for new tester to arrive. We think ours may be no good.

I tried starter fluid and that didn’t work either.

I can’t use a code reader as the codes were wiped once the battery was removed/replaced.

SOS, I love this car but I am at a complete loss.
I am waiting for the spark plug tester to arrive, it may be that or I’ve read immobilizer. Any guidance is needed and appreciated!