weird fuel pump behavior ???

[Mish]

Hello,

 

recently I acquired a 1987 1800 Leone Wagon. Fist thing I discovered was that originaly, it was a turbo version, but previous owner has removed the turbo and switched it to normaly aspirated carburated version. Everything looks fine and works fine, but I am left wondering at one thing.

 

After acquiring the vehicle, I became aware of constant measured ticking sound from somewhere inside the dash. After reading this site I dismantled the dash and discovered that fuel pump test connector (green one) is constantly connected.

 

I disconected it and....the car would start the first time, but after 10 seconds it turns off. Subsequently, it would not start at all.

 

With test connector disconnected, upon turning the ignition to the ON position, I hear fuel pump click once, so I presume that fuel pump itself has electricity, but it does not maintain enough pressure in hoses for the normal fuel supply.

 

When I connect the test connector back, car fires up immediately and everything is normal (if driving under test connector is considered normal ).

 

 

Has anyone stumbled upon this type of situation before ?

 

 

I hope that you can read this, since english is not my primary language .

[daeron]

Your English seems fine to me Let me know if I let *my* english slip too far.

 

My guess is that they used the stock fuel pump wiring for the carby pump, and since the system wasn't recognizing that the engine was running, it would not turn the fuel pump relay "on" any other way. The FI system will only run the fuel pump for a shirt while after the key is on, and while the key is cranked, if it doesn't get the message that it is running. I am not sure exactly how this signal is relayed to the computer on the turbo models, but when the green connectors are plugged in it bypasses all that and cycles the fuel pump relay.

 

you COULD simply wire the fuel pump yourself, to be on with the key.. or find some way of installing a fuel pump relay that would be energized only with the car running.. I am not 100% certain how carbureted models do this, but a look at a service manual ought to set you straight.

 

Hope This Helps.

[Mish]

Your English seems fine to me Let me know if I let *my* english slip too far.

 

 

Hope This Helps.

 

Thank you for shedding some light on this issues, I will look into service manual.

[daeron]

I was kinda hoping someone with Carb-model experience would chime in by now.

 

You DO have a low pressure fuel pump on the car, instead of the original, high pressure, fuel injection pump? The pump for fuel injected cars runs at about 50 PSI output, where the carb pump runs about 5 PSI.

 

 

The biggest reason NOT to simply hard-wire a line to your fuel pump so that it comes on with the key, is safety. When the engine is not running, the fuel pump should cut off. This way, if you are in an accident, and the engine dies, the fuel pump does not continue pumping fuel into what may be a fire hazard. Until you can figure out a "safe" way to wire the pump on your own, I would stick with the green connectors staying plugged in, and live with the noise.