My 1989 420 sel will only start readily in the Am if I do as follows.. turn the key off and on app 7-10 times.. for 4-5 seconds at a time .. fuel pump can be heard.. crank car and floor accelerator.. then let off.. sometimes I have to do this twice.. If I just crank.. it can take 3-4 min to actually start..any help or guidance would be appreciated

 

There is a cold start valve. I believe the 11 switch is what makes it work.

I have no idea how to test it all, since I never had the problem.

 

There is few thinks to be checked on your car.
1. Cold start valve- extra fuel injector build into intake manufold.
I checked it ones on my 280 M110 engine by removing it, putting cup under it and cranking the engine. Nice fuel spray for few seconds should come out of it.
2. Fuel pump relay
Burned out (dirty) contacts on little 40 Amp relay soldered into circuit board
3. Fuel pressure regulator
Could be stuck in opened position. Has two fuel lines and one vacuum hose going to it. One line from fuel distributor and the other going back to fuel tank.
4. Fuel check valve.
Located right next to fuel line entering the fuel distributor, keeping the fuel system pressurized and stoping any back flow.
5. Warm up regulator
Connected in series into fuel line from pump/filter to distributor
Before you do anything, check all the hoses and connection around your fuel pump.
Bernard

 

i had same problem when u put the and make the Dashboard lights on wait for 3 seconds and try to turn it on

so check the pumber and the Spark Plugs