My 1987, 190E, 2.3 starts fine when cold, but when warmed up and shut off,
will start right back but if shut off and sits for a min or two it won't start for a hour or more. I have replaced complete fuel system, overvoltage relay, everything from the fuel tank on except the fuel pump. Car runs great in town and on the road, I just can't shut it off and expect it to start again unless I wait for a hour or more? Any help with this problem would be of great help!

I had the same problem on 1988 190e 2.3. I even replaced the fuel distributor; although it was a used one. It turned out that it was the fuel distributor. What was happening is that the distributor was leaking and the gas was pooling on the butterfly on the air intake. When I would go to start the car it would dump the raw gas.

I change the fuel distributor with another used one it has worked just fine.

Hope this helps.

Gards

I would check your fuel pump voltage and your fuel pump relay before even going near the $distributer$.

I have completely replaced everything as the car sit up for about a year due to a bad fuel dist. I replaced with rebuilt one and then replaced the rebuilt one under warrenty but still no change. Regulator has been replaced as injectors, idle control valve, etc., etc.. Only thing I haven't replaced is the fuel pump that I can think of? Car acts like a vapor lock or something. I have a little ways to go, but the car has just been painted, interior cleaned up nice but will add wood kit, already added leather wheel. S600 style grill, euro headlights, clear corners, new tires and brakes, several little things like mb plate frames and logo plate, valve stem covers and caps, etc.. Sony MP850 with pioneer speakers, dash cap and cover. Painted all the trim and car orginal mb blue. Really turns heads and runs great! everything works but just this starting problem to go... Thanks for all the help.....

Charles

Fuel pressure checks fine as does the pump voltage. Car will not start when warm even with starting fluid? Could it be some where in a voltage other than the overload relay and fuel pump relay? Any help Please......

Have you checked / replaced the Water Temp. Sensor, a.k.a. Temp Sensor for CIS?

Try the coolant temp sensor. On the cylinder head, near the rear. This is the one with two connections to two different wires. One for the fuel ECU, one for the ign module. Both terminals should show a resistance to ground. This varies with temperature. If one side is open to ground, try switching wires for a temporary fix. The fuel is much more sensitive to temperature than the ignition is. If the side presently on the fuel side is open (broke) it's telling the engine you're parked in the Arctic when the engine is really warmer. Result: too much fuel. It made a dramatic difference on my '87 260E.

Good luck,

__________________
Norm in NJ
Next oil change at 230,000miles