83' 500SL no start

[Marc]

Hi Everyone,

I have an 83' 500 SL, drive it a few times a month during nice weather months. It usually starts right up and runs fine. Last fall I had a project and needed some room in my garage for a day so I moved the car in front of my house. It started and ran fine, no problem. The next morning I went to move the car back into the garage and it would not start. It cranked but wouldn't start. Spent all morning trying to get it to run but it didn't start. I thought certain it was a no spark issue because it never even tried to run. However, I pulled a plug to verify and found I had plenty of spark. I killed the battery so I put a charger on it. Came back 8 or 10 hours later and the car started right up. No idea what this issue was. It started and ran fine ever since.

About a week ago, I hadn't driven it for a few weeks but I needed to move it to another garage I have for some cosmetic work. It started and ran absolutely fine for a 30 mile trip. Parked it in the garage. Started my repairs. A couple of days later I wanted to move it out of the garage and it wouldn't start. Same issue just cranks and cranks but won't start. Gave up for the day. Came back a couple of days later cranks but won't run. After trying for a while I did actually get it to start. But it wasn't like normal. It cranked forever, when it finally did start the rpms never went up as usual it just chugged at about 200rpm, doing anything, touching the throttle, moving the air intake plate, caused it to stall. Got this to happen a couple of times then back to just cranking. In between when it just cranked and the day that it just chugged. I had ordered an ICU since they are inexpensive now, I figured this couldn't hurt. So today I come back and again it just cranks. I swapped the ICU though at this point I didn't think it would make a difference. It didn't. I poured some fuel down the air intake. Still did nothing. I pulled a spark plug just to make sure and I do in fact have spark. The plug though didn't look wet. I took a squeeze bottle and squirted fuel into the cylinder. replaced the plug and still absolutely nothing. So, I'm stumped. I have fuel. I have spark. But it didn't even try to run. I can hear the fuel pump running. I don't know what to chase an ignition or a fuel problem? If anyone's got any experience with a problem like this. I love to hear your thoughts.

I appreciate the help.

thank you