Discussion
Chaps
After a bit of advice as I spent a large chunk of yesterday trying to resurrect a mates 500 griff which hasn't been driven for 14months.....
Still one replacement battery later it has power and appears to turn the alarm and immobiliser off, however after much tracing of wiring and running the fuel pump etc we did get it to fire up and run however this was only after removing the relay next to the hazard flasher unit and it continued to run when this was replaced.
So obviously I had disturbed something which then gave power to the ECU as we couldn't get it running again after that..
When does the ECU take its power from ?
Is there a relay for it? as there's no power at the ECU fuse.
Also the 1st priming fuel pump relay isn't switching unless bridged out to earth which isn't ideal.
Now if the ECU controls the switching off of the first relay ( as its supposed to run for 2 seconds then turn off until the engine is running) this points to something up with the ECU supply again.
Any pointers gratefully recieved
Matt
After a bit of advice as I spent a large chunk of yesterday trying to resurrect a mates 500 griff which hasn't been driven for 14months.....
Still one replacement battery later it has power and appears to turn the alarm and immobiliser off, however after much tracing of wiring and running the fuel pump etc we did get it to fire up and run however this was only after removing the relay next to the hazard flasher unit and it continued to run when this was replaced.
So obviously I had disturbed something which then gave power to the ECU as we couldn't get it running again after that..
When does the ECU take its power from ?
Is there a relay for it? as there's no power at the ECU fuse.
Also the 1st priming fuel pump relay isn't switching unless bridged out to earth which isn't ideal.
Now if the ECU controls the switching off of the first relay ( as its supposed to run for 2 seconds then turn off until the engine is running) this points to something up with the ECU supply again.
Any pointers gratefully recieved
Matt
should be two metal-cased Bosch relays on flying leads by the ECU.
One is the main power relay which powers the ECU. The other powers the fuel pump. The control circuit for the fuel pump relay is earthed via the ECU, from memory the supply side is ignition switched although it might have been permanent, it's been a few years since I played with it.
One is the main power relay which powers the ECU. The other powers the fuel pump. The control circuit for the fuel pump relay is earthed via the ECU, from memory the supply side is ignition switched although it might have been permanent, it's been a few years since I played with it.
350matt said:
Chaps
After a bit of advice as I spent a large chunk of yesterday trying to resurrect a mates 500 griff which hasn't been driven for 14months.....
Still one replacement battery later it has power and appears to turn the alarm and immobiliser off, however after much tracing of wiring and running the fuel pump etc we did get it to fire up and run however this was only after removing the relay next to the hazard flasher unit and it continued to run when this was replaced.
So obviously I had disturbed something which then gave power to the ECU as we couldn't get it running again after that..
When does the ECU take its power from ?
After a bit of advice as I spent a large chunk of yesterday trying to resurrect a mates 500 griff which hasn't been driven for 14months.....
Still one replacement battery later it has power and appears to turn the alarm and immobiliser off, however after much tracing of wiring and running the fuel pump etc we did get it to fire up and run however this was only after removing the relay next to the hazard flasher unit and it continued to run when this was replaced.
So obviously I had disturbed something which then gave power to the ECU as we couldn't get it running again after that..
When does the ECU take its power from ?
The ecu has a permanent feed from the battery - hence disconnecting the battery 'resets' the ecu. But it also has an ignition switched 'feed' so it knows when the ignition's on. Don't forget that this feed is likely the one switched via the immobiliser. Could the immobiliser be playing up?
350matt said:
Is there a relay for it? as there's no power at the ECU fuse.
I can't remember but I think the silver ecu relay is ignition switched - so there should be a permament 12v to the supply side - and the other ecu is ecu-switched to control the fuel pump. As GreenV8S says, the ecu switches the control earth of this relay.
350matt said:
Also the 1st priming fuel pump relay isn't switching unless bridged out to earth which isn't ideal.
Sounds like the ecu isn't switching it. Does the fuel pump 'prime' OK?
350matt said:
Now if the ECU controls the switching off of the first relay ( as its supposed to run for 2 seconds then turn off until the engine is running) this points to something up with the ECU supply again.
Or the immobiliser. I'd bypass all the immobiliser circuits, and take that out of the equation.
Edited by griffter on Monday 23 April 08:42
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