My new 1992 SL500., now no start
 

1992 SL500 no start - I bought a SL500 110k mi for dirt cheap, needing fuel distributor, running very rich, drove it home, started up every time instantly. I installed a new FD diaphragm, o-rings and cleaned up internally. All parts went back where they were originally. Piston moves freely, no leaks. Old diaphragm was really bad, many small holes, EHA doesn't leak.
Installed new cam sensor this morning as old one was cracked, then pulled apart when I tried to pull the connector off. Still, cranks for 10 seconds before it it gets on the verge of running, but will not start.
Checked both rotors and dist. caps -OK, new Bosch non resistor plugs.

Are you getting fuel?

When I crack the fuel lines at the injectors fuel sprays out.
I'm going to check the coils today.

Pull the spark plugs, they will be carbon fouled giving the sort of wanting to run symptom.

The carbon conducts electricity allowing it to flow down the insulator rather across the gap. A propane torch can be used to burn the carbon off, be sure to gently heat the plug up. Rapid heating can lead to a cracked insulator.

Brand new plugs last Thursday

Pulled FD back off,
Took out the plug on the lower, sprayed carb cleaner and air but apparently doesn't come out anywhere? Clogged port?

Most likely the fuel mixture is out of adjustment, try adjusting first in 1/4 turn increments.

Make sure to keep track of how much you have moved the adjustment so you can return to the base setting.

Also, after correcting air/fuel mixture, check into any vacuum lines as mine were all cruddy and most were cracked after 2 decades. Maybe those should be done first...

I rebuilt the FD, didn't start, got a 560sel FD from junkyard, started but over rich white smoke, reinstalled SL500 FD, enriched adjustment 3 turns, runs great. The mechanic that had worked on the car before the previous owner gave up must have screwed it way out. BTW- The 560 FD plunger travel is 1/8 + more than the SL500. Changing the oil and making adjustments tomorrow. PO had champion resistor plugs in it, also one sparkplug wire was cut by a bracket in front. Also the best way to test for fuel delivery, bypass mas relay with fused wire, don't start engine, only turn on run for fuel pump to run, turn off, push down on air valve, watch fuel rise in fd ports. Should be even in all ports, no fuel = clogged port/screen, possible leaking o-ring?

I picked up a bunch of fuel injectors 10+, more than half leaked or after cleaning had bad spray pattern. Used Walmart carb cleaner, with hose in injector, sprayed, let soak, blew out with air, used air to open pintle, put 2 pieces of toothpicks in seat to hold open, into the ultrasonic cleaner for an hour or 2. Carb cleaner and air again.