G4X ECUs have up to eight independent injector drives. This means that for most engines sequential injection can be used. Depending on the number of Injection Drives, the following Injection Modes may be available:

·Single Point Group

·Multi Point Group

·Sequential

·Sequential/Staged

·Group/Staged

·Sequential/Multi-Point Staged

·Semi-Sequential

 

Single-Point Group Injection

A single injector (sometimes two) is used to supply fuel for all cylinders. Normally this injector is placed just before or just after the throttle body. In this mode the injector(s) are fired once per TDC. The injector should be driven by Injector Drive 1. If two injectors are used then the second injector should be driven by Injector Drive 2. This mode can be setup to use between 2 injector drives

 

Multi-Point Group Injection

This mode should be used if each cylinder has its own injector, but there are too many cylinders or insufficient triggering to use sequential injection. In this mode the injectors are fired in two out-of-phase groups with each group firing once for every 360 or 720 degrees of crankshaft rotation (depending on the Injection Rate setting). Wire e-ach injector to its own drive or pair injectors if there are not enough drives.

 

Sequential Injection

This mode should be used if each cylinder has it’s own injector providing the following criteria are met:

1.There must be one Injector Drive for each cylinder.

2.There must be sufficient triggering for the ECU to calculate the current engine position in the 720 degree engine cycle. This means that a second trigger sensor is required for synchronisation and this must use an appropriate trigger wheel driven off of the camshaft (or driven at half the crankshaft’s angular speed).

In this mode each injector must be correctly wired to its own injector drive so that the injector can be fired. The timing at which the injectors fire is configurable within PCLink Tuning Software.

The firing order of the engine is NOT important at the wiring stage as the firing order will be entered into the ECU via PCLink Tuning Software. Wire each cylinder to its corresponding injector drive number (wire cylinder 1 injector to injector drive 1, 2 to 2, 3 to 3 etc...).

Set the 'Injection Mode' to 'Sequential' when using this configuration.

 

Group Fire Staged Injection

This mode can be used for staged injection when the criteria required for sequential staged injection are not met. In this mode the number of injection drives used can be specified using the 'Active Drives' setting. Irrespective of the number of injection drives used, wire the primary injectors to odd numbered Injector Drives (Inj1, Inj3, Inj5, Inj7), wire the secondary injectors to even numbered Injector Drives (Inj2, Inj4, Inj6, Inj8). In this mode all primary injector drives are fired at the same time (group fire) and all secondary injector drives are fired at the same time (group fire). Set the 'Injection Mode' to 'Group/Staged' when using this configuration.

 

For example on a V8 engine with a primary and secondary injector per cylinder the following table shows how the injectors should be wired:

 

 

Be sure to follow the injector wiring guidelines to that the maximum injector drive current is not exceeded.

 

Sequential Staged Injection

This mode allows the use of staged injection where the engine uses primary injectors that operate at all times and secondary injectors that only operate at high load/rpm. This arrangement is useful in applications with very high fuel delivery requirements that would normally require extremely large injectors. Very large injectors make tuning difficult at low loads (idle and low power operation). With staged injection one smaller set of injectors operates at low load giving more precise control. At higher loads both sets of injectors become active to supply the required fuelling needs.

This mode can be used to provide full sequential injection on both the primary and secondary injectors. This mode requires that the engine have sufficient triggering to calculate crankshaft position and the position in the firing order (i.e. a sync signal is required) and requires two injector drives per cylinder.

Wire injectors as shown in the preceding table. On engines with 5 or 6 cylinders Sequential/Multi-Point Staged must be used. Engines with 8 or more cylinders must use Group Staged Injection.

Set the 'Injection Mode' to 'Sequential/Staged' when using this configuration.

 

Sequential/Multi-Point Staged Injection

This mode can be used to provide full sequential injection on the primary injectors and Multi-Point injection on the secondary injectors.

Injector drives 1 to the number of cylinders are allocated as the primary injectors for the cylinders of the same number and the next two injector drives are the secondary injectors.

 

 

Semi-Sequential Injection

Semi-sequential fires injectors in groups of two, it allows injection timing control and minimises the time available for fuel to condense on the port walls. This mode requires sufficient triggering to determine engine position in the 720 degree engine cycle. In this mode, ideally injectors are wired in pairs according to the firing order with the pairs wired to the injector driver that corresponds to the lowest numbered cylinder in the pair. However, with some firing orders this is not possible. In cases where that rule is not possible the idea is to group injectors in such a way that the time for fuel to sit in the port is minimised. Select Semi-Sequential Injection Mode when using this wiring configuration.

To clarify how this mode works, this mode works the same as sequential injection but only allocates the first half of the injectors.

 

Examples:

·6 Cylinder, firing order 1 5 3 6 2 4. Works nicely as per rule. Fuel sits in port for 120 degrees longer on the higher numbered cylinder in the pair than the other.

·Injector drive 1 is wired to injectors for cylinders 1 and 5.

·Injector drive 2 is wired to injectors for cylinders 2 and 4.

·Injector drive 3 is wired to injectors for cylinders 3 and 6.

·8 Cylinder, firing order 1 8 4 3 6 5 7 2. Does not follow rule due to firing order. Pairs as per OEM Toyota 1UZFE wiring.

·Injector drive 1 is wired to injectors for cylinders 1 and 7.

·Injector drive 2 is wired to injectors for cylinders 2 and 8.

·Injector drive 3 is wired to injectors for cylinders 3 and 5.

·Injector drive 4 is wired to injectors for cylinders 4 and 6.

·10 Cylinder firing order 1 10 9 4 3 6 5 8 7 2. Follows rule but note that the order of the high and low cylinder in each pair changes. eg in the 1-10 pair, cylinder 10 gets its fuel 72 degrees before ideal. In the 9-4 pair, cylinder 9 gets its fuel 72 degrees after ideal.

·Injector drive 1 is wired to injectors for cylinders 1 and 10.

·Injector drive 2 is wired to injectors for cylinders 2 and 7.

·Injector drive 3 is wired to injectors for cylinders 3 and 6.

·Injector drive 4 is wired to injectors for cylinders 4 and 9.

·Injector drive 5 is wired to injectors for cylinders 5 and 8.