car stalls then won't turn over

[Cogsworth33]

I've recently purchased a 66 230SL. Drove well on test drive. Had mechanic inspection prior to purchase. 145 across all 6 cylinders. It was parked quite a while before the cosigner had it tuned up for sale. After getting the car delivered when I first drove the car it went 10 miles then at a stop it idled a bit rough - pushed the accelerator down the car hesitated but then caught and drove forward but felt like it was starting in 4th gear (it's an auto but that's how I describe the feeling). After another couple of miles stopped at a light and this time instead of going when I hit the accelerator it dies and won't restart. After about 30 minutes it restarts but by that time I've called a flatbed tow to take it to the shop. I let it run then turn it off. Try to restart and it won't start. I thought maybe old fuel or filter but the shop checks this out and the diagnosis is faulty voltage regulator and alternator. They rebuild the alternator and pick up a new voltage regulator. I pick up the car and drive 25 miles and all is fine. Then it does exactly the same thing - at a light feels sluggish at a stop but catches. Next light, dies completely as I try to accelerate. Turning key does nothing but turn the battery light on. No starter engagement. Back to the shop. By this time I was closer to the shop in downtown Chicago (vs. the burbs where I had it delivered). This shop says it is the ignition switch. This didn't make sense to me or the other tech but they replaced and the car starts now. Are these two separate, unrelated issues (ignition switch/stalling) or is one possibly causing the other?

[ctaylor738]

Who knows?  I can see the ignition switch wearing out and not able to engage the Start position when the key is turned.  Alternators and regulators fail all the time.  It's not unusual to have a series of failures when one of these cars gets back on the road after sitting for a long time.

But this also suggests to me that you are running out of fuel after driving for a while.  I would check fuel volume if it gets in a die-no-start situation again, and also have a look inside the fuel tank through the fuel gauge sender hole to see if there is any rust in the tank.  If there is, it will clog the tank strainer after a period of driving.

[Jonny B]

Will add the customary note of caution. When/if you open the gas tank, be VERY careful about ignition sources, sparks and such.

[Cogsworth33]

Thanks. As I suspected the ignition switch wasn't the problem. I'll start looking at the fuel side. I was surprised that the fuel system wasn't the diagnosed issue at the onset. The alternator and ignition may very well have been going bad and getting the car back on the road after a decade of 100 mile years is probably going to shake some things out.