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Discussion Starter #1
Hi, I just registered. I am normally on the MGB forums, but my father-in-law's 380 SL stopped on me and it's in my garage. A week ago, I put in a new radio for him, I stopped for gas while taking it home. It quit about 5 blocks away and I had it towed home. I figured fuel filter, done .. no change. It will start and run with starting fluid is telling me no fuel to the engine. Tested and put power to fuel pump.. it runs. Jumper wire to "fuel pump relay" .. the fuel pump runs continiously (even with key off) and engine WILL start and run smoothly. Replaced with TWO other (correct part number) relays, no change. I checked and cleaned all fuses, pulled and replaced as many electrical connections as I could find. No change. I have a hot battery, fuel pump that runs, engine that will start and run with a shot of starting fluid and a jumpered relay. What else will shut off fuel or signal it not to flow?
Thank you in advance if you might have an idea to get it running. RMikeM
 

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1972 280CE
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4,211 Posts
Mike

I'm also on the MG forums (although I regrettably sold my MGB this year). I believe that the fuel pump relay is behind the glove box liner and I suspect it's gone out. Is that the one that you jumped?

It looks like this and new ones are available aftermarket.

 

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500SLC #2624. Black on Black.
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So you're saying it starts and runs with the fuel pump relay jumpered, but it won't when it's not.

Sounds to me like you've tracked down the source of your problem.

Or have I misread your post?

And welcome!!! :D
 

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1986 560 SL
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7,390 Posts
Except he says he replaced the relay, TWICE.

Sounds like a faulty signal to the relay, rather than a faulty relay itself.

There is an elaborate test procedure in the service manual http://www.startekinfo.com/StarTek/outside/11883/?requestedDocId=11883

Most folks just replace the relay and ignore the procedure b/c of its complication and the difficult access,
but in this case .....
 

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Had exactly the same symptoms. After several tests and relay bridging all indications pointed to the ignition switch. On dismantling the switch to inspects the contact points several bakelite tabs that open and closes the contact points dropped out of the switch. Replaced the switch with a new one and all worked perfectly.




 

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Discussion Starter #6
I'll look at the ignition switch today. ... Fuel pump will run with 12 volts directly to it such as a battery charger, it also will pump and run when the original bad fuel pump relay is jumped. I have bought two more relays and they changed nothing. Can all three be bad? I will download the electrical/fuel schematics today also and try to pinpoint something from that.Thanks for the tips so far...
 
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