W124 300 12v Starting Problems

DanMorgan

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Hi,

Wondering if you could give possible solutions for a problem I have

The car won't start but it has a good ignition spark, I can hear the fuel pump working and have pressurised fuel either side of the fuel distributor (inlet and return) however no fuel to the injector when cranking over the engine.

Does this mean a faulty fuel distributor?


Regards,

Dan
 

grober

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FAULTY FUEL PUMP RELAY---- its 2 stage- Initial pressurising stage then requires an "engine running" signal to maintain power to the pump-- it may also supply a feed to the extra starting injector.
 
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DanMorgan

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R129 300SL 24V, W124 300CE, W210 E55 AMG, W140 S280
FAULTY FUEL PUMP RELAY---- its 2 stage- Initial pressurising stage then requires an "engine running" signal to maintain power to the pump-- it may also supply a feed to the extra starting injector.

Will purchase one ASAP and report back with the outcome. You may have saved me a few quid as I was going to purchase a second hand fuel distributor! :thumb:
 

grober

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Lots of posts about this on the forum if you do a search . The engine running signal is a safety feature to stop the fuel pump running in the event of a crash/engine stop situation where fuel would continue to be pumped into th engine compartment. As a test the main relay contacts can be bridged temporarily to keep the fuel pump running continuously. If the car then runs you can be pretty sure its the FPR.
 
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DanMorgan

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Hi,

I forgot to mention that when I first put the ignition on - I can hear the fuel pump 'buzz' for approximately 5 seconds. Does this mean the relay is okay?
 

grober

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Hi,

I forgot to mention that when I first put the ignition on - I can hear the fuel pump 'buzz' for approximately 5 seconds. Does this mean the relay is okay?
No it means the first "pressuring stage" is working the second stage may not. This could be the relay or its not getting the engine running signal.
 

BlackC55

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Bridge the relay to confirm. Terminals 30 and 87
 
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DanMorgan

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R129 300SL 24V, W124 300CE, W210 E55 AMG, W140 S280
Bridged the relay, however still no fuel coming from the connector the injector thus no engine start.

Any more suggestions?

Thanks,

Dan
 

GP801

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Our 280 had a similar issue with the fuel pump running intermittently. It needed both the fuel pump and OVP relays replacing to solve the issue. A dodgy OVP really seems to affect all sorts of things. Realise not the same engine but might be worth considering
 
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DanMorgan

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R129 300SL 24V, W124 300CE, W210 E55 AMG, W140 S280
Thanks for all the input. Today the issue was fixed - I bought a second hand working fuel distributor and its now fires up. I had to run the car for a while to clear up all the gasses in the engine, but it idles perfect and sound good. Just need to get a new OVP to improve the startup!
 

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