EFI Control Relay
Posted: Wed 15 Aug, 2007 7:57 am
If anyone is converting to EFI from a carb (Steve) its important
that the fuel pump is controlled either by the EFI system itself
OR by a seperate specialised "control relay"
One solution is a Bosch "Tachometric Relay".
The most common use ( and therefore wrecker available ) is off a
VK Commodore BOSCH P/N 0 280 230 005.
This is a multiple output relay that also has "cranking" and
"tacho" inputs. Fuel pump will be on whilst engine is cranking
and running but will cut out if neither signal is supplied after
around a second or two.
The connections are numbered on the relay - using standard BOSCH ID's
Terminals
30 + from Batt
31 -
15 + from ignition
1 Ignition Coil ( RPM Pulses )
50 Start Solenoid
57 Switched + for Injectors etc ( optional but good idea )
57B Switched + for fuel pump
Note : EFI fuel pump control is required by law. The consequences
of high pressure pumps left running in an accident are very severe.
Switching the + to the injectors may seem like overkill - however the
ECU grounds the injectors to operate and therefore a short etc can
leave the injectors stuck on.
An ECU failure can also produce the same results.
that the fuel pump is controlled either by the EFI system itself
OR by a seperate specialised "control relay"
One solution is a Bosch "Tachometric Relay".
The most common use ( and therefore wrecker available ) is off a
VK Commodore BOSCH P/N 0 280 230 005.
This is a multiple output relay that also has "cranking" and
"tacho" inputs. Fuel pump will be on whilst engine is cranking
and running but will cut out if neither signal is supplied after
around a second or two.
The connections are numbered on the relay - using standard BOSCH ID's
Terminals
30 + from Batt
31 -
15 + from ignition
1 Ignition Coil ( RPM Pulses )
50 Start Solenoid
57 Switched + for Injectors etc ( optional but good idea )
57B Switched + for fuel pump
Note : EFI fuel pump control is required by law. The consequences
of high pressure pumps left running in an accident are very severe.
Switching the + to the injectors may seem like overkill - however the
ECU grounds the injectors to operate and therefore a short etc can
leave the injectors stuck on.
An ECU failure can also produce the same results.