LS1 (Gen 3) Engine

LS1 (Gen 3) Engine

Information on the General Motors LS1 Gen III engine




Holden Commodore LS1 engine





 
Number of Cylinders
8
Capacity
5665cc (346ci)
Firing Order
1,8,7,2,6,5,4,3
Cylinder Orientation
(1357 RHS)








Injection System

All LS1 engines operate under sequential injection with an injector located in the inlet manifold spraying directly onto the intake valve.  Injectors are High Impedance.  The fuel system is of a non-returning type run at a fixed fuel pressure.

Early models used 230cc injectors
Later models used 250cc injectors.






Sensor Information

Trigger System

The LS1 engine has a trigger system mounted on the crankshaft that has a 24x tooth pattern.  The camshaft has a half-moon style tooth.




LS1 Crankshaft showing crank trigger system




LS1 camshaft sprocket showing half moon trigger system






Crank Sensor

The crank sensor is unique in that it is a reluctor sensor that has internal signal conditioning to convert the signal into a digital Hall Effect style.  As such the ECU should be configured as a Hall Effect crank sensor.  It uses the Falling edge of the signal which has a common timed edge. The Rising edge of the signal has unique timed signals that cannot be used by the Haltech Elite ECU range. It is located above the starter motor towards the rear of the engine block.  Gen 3 sensors are black, Gen 4 sensors are grey and cannot be used with a gen 3 crankshaft trigger pattern.



Crank Sensor Pin
Haltech Connection
A
Trigger +  (Yellow) 
B
Signal Ground  (Blue)
C
12V+  (Red)







Cam Sensor

The LS1 Cam Sensor is of a normal Hall Effect type. For Gen 3 engines it is located at the back of the engine at the top of the V.


Cam Sensor Pin
Haltech Connection
A
Trigger +  (Yellow)
B
Signal Ground  (Blue)
C
12V+  (Red)




Trigger Configuration










Ignition System

LS1 engines operate as Direct Fire with a coil per spark plug mounted on the rocker covers of the engine.  These coils have internal igniters and can be wired directly to the Haltech ECU.




Ground both pins A and B to the Cylinder Head
Set to Constant Charge with Falling edge.   Using Rising edge will damage the coils.


Dwell Time














Drive By Wire (DBW) Throttle System (for models so equipped)

The LS1 uses a single Drive By Wire throttle body.  This can only be controlled by an Elite 2500 or 1500 model ECU.
The VZ Commodore LS1 does not have the DBW Throttle and Pedal wired to the ECU.  They are instead wired to what is called a TAC Module which is in turn controlled by the ECU.

VZ Commodore DBW throttle body




Pin
Description
Haltech Connection
A
Motor Control 1
DBW 1 (Brown/Black)
B
Low Reference
Signal Ground (Black/White)
C
Motor Control 2
DBW2 (Brown/Red)
D
Low Reference
Signal Ground (Black/White)
E
5V
5V+ (Orange)
F
TPS 2 Signal
AVI-3 (Orange/Red)
G
TPS 1 Signal
AVI-2 (Orange/Black)
H
5V
5V+ (Orange)




DBW Accelerator Pedal Position

VZ Commodore Pedal















Throttle Position Sensor (Cable Throttle Models)



Pin
Description
A
5V+
B
Signal Ground
C
Signal











MAP Sensor

The LS1 engine comes with a MAP sensor located on the inlet manifold.


Pin
Description
A
Signal Ground
B
Signal
C
5V+
Calibration: Use "MAP - GM 1 Bar.cal"









Idle Control

Models that have a DBW Throttle use the throttle for Idle Control.  Models with a Cable throttle body use a Stepper Motor idle control system.

The stepper motor idle control is only supported on the Elite 1000 and higher ECU models.  
It is not supported on Elite 550, 750, or 950 ECU models.

Pin
Haltech Connection
A
Stepper 4
B
Stepper 3
C
Stepper 2
D
Stepper 1
Drive Type: Both
Steps:240
Speed:75








Coolant Temperature

Located on the LHS cylinder head near cylinder 2 exhaust pipe.

Uses Delphi connector that requires the wire to be fed through the connector first, the pin crimped, and then pull back to lock the pin in place.
Wiring is not polarity sensitive

Calibration: Use "Temperature - Holden VP V8 Coolant Sensor.cal"
Created for Haltech ECUs using a 1k pullup to 5V










Air Temperature

Located on airbox


Uses Delphi connector that requires the wire to be fed through the connector first, the pin crimped, and then pull back to lock the pin in place.
Wiring is not polarity sensitive.

Calibration: Use "Temperature - Holden VP V8 Air Sensor.cal"
Created for Haltech ECUs using a 1k pullup to 5V










Oil Pressure Sensor

The LS1 comes with a 130psi rated Oil Pressure Sensor.



Pin
Description
Haltech Connection
A
Signal Ground
Signal Ground (Black/White)
B
5V+
5V+ (Orange)
C
Signal
Spare AVI
Calibration: 0.5V = 0 psi , 4.5V = 130 psi











O2 Sensor

The LS1 comes with 4-wire narrowband O2 sensor. It is strongly recommended to replace the front O2 sensors with a wideband O2 kit such as the Haltech WB2.


O2 Sensor Wire Colours
Haltech Connection
Black (Signal)
AVI 1 or AVI 6
Grey
Signal Ground (Black/White)
White
12V+ Switched
White
Chassis Ground (not Signal Ground)
Most narrow band O2 sensors use a black wire for signal.  This is often mistaken as the ground wire.
The heater wires are not polarity dependent.  The heater ground can be pulsed with an ECU output.  Use an Injector, Stepper, or DPO for this. DO NOT USE an Ignition output.









Knock Sensor

The LS1 has 2x older design resonant style knock sensors located in the valley of the engine.

They can be used however they are prone to failure.  They are also oriented to read front to back, not bank to bank.  For better results switching to the more modern non-resonant "donut" style sensors and locating them on the outside of the block allows better bank control of knock.









MAF Sensor

Commonly deleted when a Haltech ECU is installed, however it can be used if preferred.
There are 3-wire and 5-wire MAFs available on LS1 engines.  The 5-wire type incorporates an Air Temperature Sensor



3-pin type
MAF Connection
Haltech Connection
A - Yellow (Signal)
Any spare AVI
B - Black/White (Ground)
Sensor Ground (Black/White)
C - Pink (12V+)
12V+ Switched (Grey/Red)


5-pin type
MAF Connection
Haltech Connection
A - Purple (Air Temp Signal Ground)
Sensor Ground (Black/White)
B - Tan (Air Temp Signal)
Any Spare AVI (AVI 7 Typical)
C - Black/White (MAF Ground)
Sensor Ground (Black/White)
D - Pink (12V+)
12V+ Switched (Grey/Red)
E - Yellow (MAF Signal)
Any spare AVI












OEM ECU Information









Automatic Transmission

4L80E

The 4L80E transmission requires ECU control of shifting and lock up converter.







Unique Information

Common Issues

Trigger Errors

With a cam swap it is common to have issues with the cam sensor signal occurring too close to a crank sensor edge. If the cam sensor edge swaps from before to after the crank sensor edge, or vice versa, an engine position error will occur.   Monitoring the Home Percentage of Valid Travel channel shows how close the edges are to each other.  If it is too close to either 0 or 100% then this can occur with a running engine.

Possible solutions are:
1. Try a different cam edge.  This requires a TDC Offset change of 360, so either adding or subtracting this amount while keeping the value between 0 to 720.
2. Try adding filtering to the Home.  Increasing to 2 or 3 can delay the Falling edge enough to keep it away from the crank sensor edge.  The higher the rpm, the high the Home % channel will report.



Incorrect Trigger Pattern

Mixing of Gen 3 and 4 parts can be common when a custom engine is assembled.  Most combinations will work however there is one combination that cannot work.

Crank Trigger Pattern
Cam Trigger Pattern
Will it Work
Configuration Trigger Type
24x Gen 3
1x Gen 3
Yes
General Motors - LSx Gen III (24x + 1x)
24x Gen 3
4x Gen 4
No
---
60-2 (58x) Gen 4
1x Gen 3
Yes
Generic Missing Tooth Single Tooth Home
Trigger Signal Location = On Crank
Number of Teeth = 60
Number of Missing Teeth = 2
60-2 (58x) Gen 4
4x Gen 4
Yes
General Motors - LSx Gen IV (58x + 4x)

If the engine is yet to be built and a decision is to be made as to which trigger system is best, the Gen 4 trigger is a better option that allows a wider range of cam position movement before trigger errors are an issue.  The missing tooth crank trigger also provides a higher level of redundancy as well as faster sync and engine startup.



No Crank Trigger Input

It is possible to have an incorrect crank position sensor installed. The grey sensor from the Gen 4 motor cannot be used with a Gen 3 crank trigger wheel.  The trigger pattern and sensor type must both match.






















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