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welly_59
10-04-2006, 19:02
im looking for a 12v source whic turns on with 'accessory' but STAYS on during cranking as well. its for my boost gauge, all live wires i've found go off at cranking so they aint much use!

Paul Woods
10-04-2006, 19:10
Theres an accessory live at the ignition switch mate....theres ign lives all over the place though around the dash area.

adamh
11-04-2006, 00:14
yup, buzz ign loom with meter.

you can use that live for your fuel pump too.?.. am i missing something here... this is where most motors take their feed for fuel pump.. ive spliced into scores of ign looms to immobilise fuel & starters... what i cant understand is how come your using cor to run fuel pump.... prolly straight over my head...

welly_59
11-04-2006, 00:20
umm thats what pauls instructions say to do so thats what i did! where's ur fuel pump running from adam?

adamh
11-04-2006, 00:36
um, mines not running yet!.. now, i'm assuming, but i believe paul would have fuel feed coming from the cor as its an easy option to control lots of bits from the one relay etc. ... dont want to have everbody wiring in fuel and stuff at ignition.. some motors would get messy!. now im real confused!.?... i wonder why pump needs cor to run if it is still connected to mk1 existing pump wiring..

some cars...lots, have direct thick fuel pump feed wires straight off the ignition barrel loom. ive not taken a mk1 apart at ign.. but can almost guarantee a fuel feed wire coming off there or one to a fpr. i'll check haynes wiring in morning at work... although, if you found one there... you'd have run a trace back to your spliced up loom in boot... or direct to pump under centre console... probably equally annoying as cor prob.

i wont sleep now...

Paul Woods
11-04-2006, 07:29
right just to make stuff clear folks.....the cor on both mk1 and mk2 is there to supply the fuel pump with power,on the mk1 it goes straight to the pump from cor,on the mk2 the cor output (blue wire) goes to the mk2 fuel pump relay....its the same thing really only the mk2 has two relays controlling power to the pump.The reason for this is that the mk2T fuel pump relay then controls wether or not you have a hi or lo speed power voltage to the pump.

Now the cors function is not just to supply voltage,its there as a safety cut,the G/R wire that runs to the ecu lets the ecu hold the cor contacted after cranking,so the cor initially contacts during cranking but is held shut by the ecu on this wire when running....the reason it does this rather than just a constant ignition live to the pump is that if you have an accident the engine stops running and the ecu no longer holds the cor shut=fuel pump stops pumping fuel all over the place and you dont burn to death,well thats the idea!

A constant ignition live to the blue wire on the pump will do exactly the same job to get it running and make the cor pretty much redundant but the pump will always run with ignition on rather than only running when the engine is,if you see what i mean.

I wire the engine bay and IC fans into the COR as well so that they only run when the engine does,mind you if you do this you need to uprate the EFI fuse from a 15amp to 20amp as the extra load blows it.

Hope that sheds a little light on the subject chaps.

adamh
11-04-2006, 11:03
ah, didnt think of that simple fact! safety. the cor is just a regular relay then, holding pump curcuit closed with negative from ecu on power down. i thought the cor had magical properties of sorts... !

Sponge Bob
11-04-2006, 11:23
...so so clever - if only I could design a whole cars circuitary!!

adamh
11-04-2006, 13:59
aye, he's a clever chap ..prolly jusr saved me from burning alive! thats another pint...

lodgeman
11-04-2006, 19:01
aye, he's a clever chap ..prolly jusr saved me from burning alive! thats another pint...



you're going to need a brewery soon! :hehe: :hehe:

adamh
12-04-2006, 08:54
yours is for sale right... SOLD!!!...
taking the wee that av there lodge... you never said you was an acrobat