Ignition and fuel pump relays on V8S
Discussion
G'day all,
Can anyone advise? Driving yesterday and pulled out from a T junction, shifted up from 2nd, not giving it welly as still cold - when the engine starts stuttering and missing big time.
Pulled in to a parking area and it 'felt'/sounded like no sparks...could hear fuel pump prime up though.
Changed both the relays (I keep spares) on the flying leads, and once I cleared a flooded engine, it was as right as rain.
One relay has a light blue connector base, the other has a black base. Which is the ignition, and which is the fuel pump? (Because clearly, the pump supply was OK.)
Can anyone advise? Driving yesterday and pulled out from a T junction, shifted up from 2nd, not giving it welly as still cold - when the engine starts stuttering and missing big time.
Pulled in to a parking area and it 'felt'/sounded like no sparks...could hear fuel pump prime up though.
Changed both the relays (I keep spares) on the flying leads, and once I cleared a flooded engine, it was as right as rain.
One relay has a light blue connector base, the other has a black base. Which is the ignition, and which is the fuel pump? (Because clearly, the pump supply was OK.)
Blue is fuel pump (and lambda sensor heaters, if fitted), black is ECU main power relay. Ignition is powered direct from the switch and is completely independent of the ECU, relays etc as far as I know.
From your symptoms I would suspect either a breakdown in the connector between the ignition switch and the main loom, or a wiring/fuse fault, or an immobiliser fault.
From your symptoms I would suspect either a breakdown in the connector between the ignition switch and the main loom, or a wiring/fuse fault, or an immobiliser fault.
Not sure not got the bible wiring diagram to hand at work but as far as I remember I actually think they are interdependant i./e. the circuits actually go through both 
.
Sure its not just overfueled and cut out as this would give a similar thing IMHO. Very difficult to diagnose IMHO. Can you do back to back cold checks between one of your new relays with the two you rmoved to see if anything is significantly differnt
.
Harry
. Sure its not just overfueled and cut out as this would give a similar thing IMHO. Very difficult to diagnose IMHO. Can you do back to back cold checks between one of your new relays with the two you rmoved to see if anything is significantly differnt
. Harry
Peter,
OK, thanks for the reply.
Am I being thick then, in assuming that the 'power' relay was the culprit. As I said, as soon as I changed the relay(s), she fired up and ran smoothly.
I was able to smell the petrol coming out of the exhaust as I coasted to a stop - -hence my comment about no sparks.
Actually, as I write this I think I see what you mean regarding the ignition being fed seperately....and to check the connector to the main loom. I'll have a poke around under the steering column over the w/end.
Cheers - Nick
OK, thanks for the reply.
Am I being thick then, in assuming that the 'power' relay was the culprit. As I said, as soon as I changed the relay(s), she fired up and ran smoothly.
I was able to smell the petrol coming out of the exhaust as I coasted to a stop - -hence my comment about no sparks.
Actually, as I write this I think I see what you mean regarding the ignition being fed seperately....and to check the connector to the main loom. I'll have a poke around under the steering column over the w/end.
Cheers - Nick
Pete/Harry,
Checked the 'Bible' over the w/end and I would agree with Harry that there is some inter-dependancy.
Referring to pp 113 in the bible, and it would appear that the No. 30 pin on both relays are fed from a common source.(that's one side of the solenoid energisation circuit) So, I guess that will be ignition switch controlled!.
I have cleaned/checked the connector off the ignition switch.
Checked the 'Bible' over the w/end and I would agree with Harry that there is some inter-dependancy.
Referring to pp 113 in the bible, and it would appear that the No. 30 pin on both relays are fed from a common source.(that's one side of the solenoid energisation circuit) So, I guess that will be ignition switch controlled!.
I have cleaned/checked the connector off the ignition switch.
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