82 380 SL Fuel Pump Relay - PeachParts Mercedes-Benz Forum

laboyma53 · #1 10-04-2011, 10:55 PM

The fuel pump works fine but the pump does not come on when the key is turned (to start). Checked fuses - OK. I do not know where the relay is.
Mike

nobby · #2 10-05-2011, 01:40 AM

Quote:

Originally Posted by laboyma53

The fuel pump works fine but the pump does not come on when the key is turned (to start). Checked fuses - OK. I do not know where the relay is.
Mike

But does the car actually run? The fuel pump only runs when the car is cranking or running.

I believe the relay on the 380 is behind the glove box. If you remove the glove box liner it should be staring at you.

Your ignition switch might also be the bad boy..

laboyma53 · #3 10-05-2011, 09:33 AM

Good morning and the car does start but is by adding fuel straight into the "carburator". I tested the pump prior to installing it - with a battery - it turned ON (it is brand new). History of the car - two years ago the engine blew and I installed a used one. Is there a way to bypass the relay? I appreciate your prompt response. Thank you - Mike

mbdoc · #4 10-05-2011, 09:51 AM

You can temporary remove the FP relay & use a jumper on the harness plug & make the pump run.

On the FP relay you will see terminals numbered 30 & 87, that is where you need to place a jumper wire ON the connector.

nobby · #5 10-05-2011, 09:59 AM

Quote:

Originally Posted by mbdoc

You can temporary remove the FP relay & use a jumper on the harness plug & make the pump run.

Just don't make it a permanent solution.

laboyma53 · #6 10-05-2011, 10:33 AM

So, if I connect the jumper the pump should run (bypassing the safety switch). This should "charge the fuel line" and hopefully fix the problem.
If the pump does not run - then the relay is defective?
I am going to locate the relay.
By the way - you guys are great....I do not get this can of help - not even from the dealeship......thanks
Mike

laboyma53 · #7 10-05-2011, 11:53 AM

Found the relay - by passed it - the pump runs. I had the wife crank the engine and it ran but as soon as I disconnect the jumper - the engine cuts off. Do I need a Relay?
Oh - I re-installed the relay and tried starting it - it does not. And the pump does not come on while the wifey cranks the engine. Fuses are fine.
Mike

nobby · #8 10-05-2011, 12:52 PM

Quote:

Originally Posted by laboyma53

Found the relay - by passed it - the pump runs. I had the wife crank the engine and it ran but as soon as I disconnect the jumper - the engine cuts off. Do I need a Relay?
Oh - I re-installed the relay and tried starting it - it does not. And the pump does not come on while the wifey cranks the engine. Fuses are fine.
Mike

Sounds like a relay to me. Good troubleshooting.

laboyma53 · #9 11-06-2011, 04:15 PM

Well guys - I am back to square ONE. The car stop running and did not start. I added fuel directly to the carburator and it starts just fine but cutts off. I jumped the fuel relay ( 30 - 87 ) and it starts just fine. The pump and the relay are 30 to 45 days old. When I pulled the jumper wire (#10 house wire); it was warm to slightly hot.
Miguel
NOTE: A local mechanic told me to take the fuel pump out; wire it (dont connect it); attached a hose to a bucket with clean fuel and a hose to an empty bucket - this is to flush the fuel pump clean. Also, he advised me to purchase pro15 to clean and seal the fuel tank.
Thanks guys