Help needed - mercedes sec won't start

[Skhan]

Hi fellas, first of all my apologies for not posting in the correct section but for some reason my phone won't allow me to.

I have a '84 500 sec that has been stood a while whilst being restored at the body shop. Yesterday it failed to start. It cranks over but no spark.

The rotor arm & distributor cap were replaced a few months ago with new ones. I have checked these & they seem to be fine. Also the fuel pump seems to be working as well. Any suggestions?

Thanks

 

[mazza]

Hi

check the OVP fuse
if the pump buzzzzzzzes, then its working

mazza

 

[grober]

Often when a car has stood for a while condensation in the distributer is a problem. Fuel can go off which can lead to gumming up of injection systems. The basics still apply---- spark and fuel------ You possibly haven't probed deep enough. Take out the plugs and have a look- make sure they are clean- any doubts renew. While not advocating this on a regular basis it sometimes helpful to use some form of accelerant sprayed into the inlet[ air filter off] to remind the car who is boss.
Bradex Easy Start comes to mind. You also need a strong battery capable of turning over the CAR for several minutes at a time.

ps fuel pump relays are two stage.
stage one- pressurises the system
stage two-requires an "engine running" signal to continue to pump fuel.

Just because the system pressurises- doesn't mean the engine will continue to run

the OVP is also a good call as it provides power to the engine ECU

 

[Skhan]

Thanks fellas. Got it going today.... It was the OVP Relay

 

[Skhan]

Help need again fellas - went to pick up the car today after being painted & it failed to start.

I've been told it started up fine last night. I couldn't hear the fuel pump buzzing so again changed the fuel pump relay & nothing.

Took the spark plugs out & they were wet with fuel so cleaned them up. Checked for a spark & there isn't one. HELP! Any ideas on what direction to go towards now?

 

[Dee-124CAB]

It was the OVP Relay

Did it have any welding done whilst at the bodyshop or just paint?

Its possible that an incompetant bodyshop may not have disconnected the battery (or used a surge protector?) during the welding and fried the OVP and also some wiring....

Did you change the OVP for a new one?

 

[Skhan]

It's had no welding just paint. Yes I changed the OVP for a new one