Guest ben19gti Posted April 1, 2007 I've had to wire my fuel pump to a constant live and i was wondering. Because the fuel pump is constantly pumping. {a} Is the pump not meant to be pumping all the time {b} Will it make my car miss-fire or over fuel anyway which it seems to be doin now I only know this now because i've just took it for a quick blast after having the exhaust sorted. Any help please Share this post Link to post Share on other sites
Doof 11 Posted April 1, 2007 Constant, not switched? That'll kill your battery over night. It wouldn't cause it to overfuel anyway, there is a return back to the tank for excess fuel. Share this post Link to post Share on other sites
bales 1 Posted April 1, 2007 I would say that that is pretty dangerous and you really shouldn't wire it up like that. Your fuel pump should only pump when it see's that the engine is cranking surely, so I guess that the ecu must see a signal from the distributor to show that it is cranking and then tell the fuel pump turn on. Otherwise what happens if you have a crash and your fuel pump is just sat there spraying fuel about at 30psi or whatever?! Share this post Link to post Share on other sites
Guest ben19gti Posted April 1, 2007 Sorry what i meant was, its wired to the ignition how sure are you it would'nt over fuel Share this post Link to post Share on other sites
bales 1 Posted April 1, 2007 (edited) Thats my point, so when you turn the ignition on the fuel pump starts pumping? I am pretty sure that it should only be on when the engine is cranking, thats why I said about a crash, just cos you have crashed doesnt mean your ignition won't be on. It can't overfuel as there is a return as Doof has said and it has no effect on the injector duration so it would only effect the fuelling if it was coming out at a higher pressure, but it cant as it has a return for this reason. Edited April 1, 2007 by bales Share this post Link to post Share on other sites
Guest ben19gti Posted April 1, 2007 I know about it pumping constant if i crash. But my question was will it over fuel causing it to bog down when i tow it? I'm thinking it will but not 100% Because even if it was goin back down the return it would be building pressure? i assume Share this post Link to post Share on other sites
bren_1.3 1 Posted April 2, 2007 (edited) But my question was will it over fuel causing it to bog down when i tow it? I'm thinking it will but not 100% doof and bales have told you twice it wont overfuel. the return line takes away any excess fuel. Because even if it was goin back down the return it would be building pressure? i assume the fuel pressure regulator on the fuel rail sorts all that out. it doesnt matter if its 1000 psi at the pump, as the FPR will drop the pressure to the desired level for the injectors. Edited April 2, 2007 by brens_1.9_wide_arch Share this post Link to post Share on other sites
