Fuel Supply Problem to Engine

[R5NI]

I have recently undertaken a restoration project of a 1988 Renault 5 GT Turbo for my Grandfather, but have encountered an obstacle with fuel supply to the engine, and would appreciate it if anyone could advise on potential problems.

To give some background I have currently replaced oil, oil filter, fuel filter, battery, spark plugs, distributor cap and rotor, and ignition leads.

When I turn the ignition on, the fuel pump does not start. I tested the functionality of the fuel pump by bypassing the heavy red and white terminals on the fuel pump relay and it operated successfully, priming the fuel lines and allowing the engine to start. The engine runs for approximately 30seconds and then dies due to fuel starvation, but I don't know how to correct this. I suspect the fuel pump relay is not functioning but don't know how to be sure.

Should the fuel pump only activate when the ignition is turned on to prime the fuel lines, allowing the car to start, and the car then essentially operates on a pressurised fuel system, or is the pump supposed to run continuously? Could I possibly have a fuel pressure problem also?

Sorry for the essay but any assistance would be very much appreciated.

[Ash-Lee]

The fuel pump should run constant. It also should only run when the engine is turning (it uses signal from the TDC sensor)

With the relay bridged, does the pump work all the time? If it starts and then stops maybe the fuel pump is failing? Attach 12v directly to the pump to be sure.

[R5NI]

Thank you very much for the reply.

Yes, the pump runs continuously with the relay bridged and then activates what I'm assuming is a return pump once enough fuel gets to the engine.

Does this sound like a fuel pump relay failure and if so can you give any guidance as to where I could get a replacement?

[R5NI]

I removed the TDC sensor and cleaned off any corrosion but the fuel pump is still not activating automatically to start the car or when the engine is running. Can anyone please advise what could be causing this?

[r555gt]

Happened to mine a few years ago. Have you replaced the fuel pump relay ? Should be under the passengers side. Definetaly sounds like the relay mate, you can get upgraded ones on ebay or a second hand replacement relay should sort you out.

[R5NI]

Thanks for the reply because the electrical fault is really starting to test my patience as the rest of the car is in good condition but I'm unable to get it on the road until I correct the fueling issue.

No I haven't replaced the fuel pump relay as I wanted to be sure it was the failure so I'm not wasting £50 but am more confident in it being the fault after hearing that you encountered the same problem. Was the one you purchased on ebay green as opposed to the standard black one?

[r555gt]

Sorry for late reply mate, i ended up just buying a second hand relay, one way you could check the fuel pump is run a cable from the battery straight to the fuel pump to see if its the pump thats failing, if u run a cable from the battery just remember to fuse it or its will melt lol i know from experience lmao.

[anaisac70]

I removed the TDC sensor and cleaned off any corrosion but the fuel pump is still not activating automatically to start the car or when the engine is running mutuelles TNS. Can anyone please advise what could be causing this?

For a long time I sought a way to clean the way, thank you for this topic.