no supply to ecu...fuse ???? where

[foggylad69]

had a major missfire with my 93 chim 4.0..unfortunateley i bought the car like this.
changed everything on the engine then found no constant +12volt supply to the ECU or relsys.(browncables / fuses hanging seperate)
have had all the fuse box and wiring out but cant seem to find an inline fuse or anything...even had the dash out..but no joy.
any ideas to the location or the source of the large brown cables?they dont seem to come from the fuse box.

[spend]

IIRC, my 93 ECU bits pick up ignition switched supply from Fuse 12, but the persistent supply is from fuse 2. This is a red cable at the fusebox end, but spliced into the LR brown cable in the umbilical length of loom (after a long loop round).


Dave

[foggylad69]

cheers Dave..was looking for brown cables...lol...it is a TVR...pmsl
Will go and try and find it ....seems Im only on about 7 volts...wondering now what else could be affected ? Is the supply to the Fuse box on a main fuse somewhere ? something that could be dropping the voltage / current ? If all else fails I will run a supply from the batery for now.....seems this thing has been running without the ecu for ages.....I think the only reason it ran is due to the fuel pump being directly wired into the ignition circuit !

[foggylad69]

Well the supply problem was the fuse box.. but still the misfire ! Downloaded some great fault finding docs from BLITZRACING and got loads of info from Mark there....top chap.
Seems that one of the recently fitted new lambda sensors doesnt work...hence that bank missfiring..... I would have sworn it was an ignition fault, but as Mark pointed out...Its better to go through everything with a multi meter first before changing anything...A LEASON LEARNT, the expensive and soul destroying way !