random misfire!! .please help.

kinglarry001

the fuse blew again today!!!

stopped at a shop, started her up and went to pull away, and died. checked. same fuse!!!!

could the ecu be faulty/on way out?

as this could explain missfires and the reason for the fuse blowing.

ecky1972

try changing the relays first as i think that wil be a bit cheaper for you like ephid0r said i think i have them from my old car but will have to check as i took them out

kinglarry001

could the relays be causing the ecu fuse to blow and the misfire?

ecky1972

kinglarry001 said:
could the relays be causing the ecu fuse to blow and the misfire?

i wouldnt know mate

kinglarry001

do you still have your ecu if mine is faulty?

kinglarry001

but if faulty ecu, wouldnt other codes come up?

.................and can opcoms check timings?

ecky1972

kinglarry001 said:
do you still have your ecu if mine is faulty?

yes mate

kinglarry001

ephid0r said:
i would replace your 2 purple relays also in engine bay

one os for fuel pump relay and the the other is for the ecu

as they are the same colour, are they exactly the same?

vocky

I think they are the same

kinglarry001

thats ok. was just checking they should be. as my two are exactly the same. cheers mate.

MikeS

suggest u get a haynes manual and find out what is hooked up to that fuse apart from the ecu relay

for it to pop it is usually earthing somewhere it shouldnt

if your ecu was faulty m8 your car wouldnt be starting

kinglarry001

according to the haynes manual. the only 2 things connected to that fuse, is the engine main relay and theengine management control unit.

what if one of the boards/circuits was slightly loose, or poor connection inside the ecu?

kinglarry001

and the fuel pump relay also connected to that fuse

kinglarry001

so to make a fuse blow, you think it could be a poor earth connection?

edited:

tested the resistance between the negative terminal on the battery and the connection on the ecu. it was 0.

kinglarry001

just looking at the wiring diagram in the haynes manual. there are quite a few things connected to the engine main relay. so if there was a fault with one of these components (eg the ignition coil) say dodgy eart on it, would that then not f*** the relay first?

MikeS

yeh but look closer

the fv6 20 amp fuse is the only fuse in the engine bay with that rating plus it connects to either fuel pump relay or engine relay or ecu

so in essence the fuse would go first

you got anything hooked up the battery like an amp ?

i have heard of overheated relays causing shorts

kinglarry001

yeah, i have two amps in the boot.

when i was looking at them last night, they were quite warm. think i will uy couple more and replace them.

worth a try.

thinking about it during the night, the fault could be any oneof the things thats hooked up to that fuse, via either of the relays! the thing is, everything that is connected to that fuse is something i have changed on the car! coil pack, injectors, fuel pump, oxygen sensors.

only thing i havent touched that the fuse protects, is the surpressor.

if say the conductors to the oxygen sensor (gather thats the lambda sensor) touch, due to the insulation melting or rubbing, would that blow the fuse?

MikeS

the only 20 amp fuse in your engine bay is wired up to 3 things

fuel pump relay
engine relay
ECU

kinglarry001

and the engine relay controls the injectors, coil pack, surpressor and oxygen sensors.

so if a faulft occurs in one of those items(or the cables to them) then wouldnt that trip the fuse?

MikeS

i would replace the relays first m8

« Previous Page Next Page »