Fuel Pump problem

[nopap]

Hello,
I'm the owner of a french buggy based on 1600i engine, registered on www.1600i.de car number 205
if you are interested in having a look.

I have a difficult problem with the engine since a while that i'm trying to solve,
and maybe someone could help with some ideas:
The fuel pump does not provide enough gas for some reason:
when i switch on ignition, the pump is supposed to run about 1 minute, on mine it's 3 seconds...
then when running i can hear the pump relay turning on and off so fast it's like a buzz sound.
Relay is of course brand new...

Of course the car does not run properly like that: the previous owner's mecanic did some hack and
made the pump run permanently as soon as ignition is on. That's fine, the car runs great,
but since a while with an idling problem that i suspect related
to the pump giving too much pressure...
This also means that the pump works fine !

The Digifant has no error in vag-com.

Does anybody has an idea why the pump would not run as expected ? I guess the ECU is providing on/off
signal to the pump, of does it mean my ECU is in bad shape ?

Thanks for any help ! And sorry for the english, i don't speak much german...
Emmanuel.

_________________
N°205

[Red1600i]

Hi.

If you switch on ignition the pump runs 1-2 seconds.... pssssssssst. Seconds, not minutes.

If the relais has a problem, check also relais J176 for the power supply of the digifant. It breaks internally and makes really strange errors like accelleration, no idle....

The ecu uses a low signal output to trigger the fuelpump relais. Check it with a logic tester, but take care, the ecu supplies only 100-200mA, not more and there is no fuse! The transistor is the fuse

Check the 12V supply for the relais, probably relais J176 was (ab)-used for this signal, there is only less than 1A available with J176... maybe somebody abused it as a supply for the pump. Thats the noise you hear and the pump will not run with full power.

Martin