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All about the G10
The Geo Metro gets amazing gas mileage due in large part to its tiny 3 cylinder engine, known as the G10. Its name designates its 1.0 liter displacement. Metros in the US came standard with the G10 from 1989 until 1994. In 1995 they introduced the 4 cylinder
but the G10 was available until the end of production on 2 door models.
Standard G10s with throttle Body injection are rated 55hp, turbocharged models achieved 73 HP (designated
was specially detuned for extra mileage, and was rated 49 HP..... (
Except for some early models, all G10s share the same block and cylinder head. Sensors on the intake manifold and the thermostat housing changed for some generations. Early models were carbureted, but soon they upgraded to GM's throttle body injection (TBI), where one injector feeds all three cylinders. Some later models and sport models had multi-port injection (MPI), meaning one injector on each cylinder.
Most Japanese cars have interference designs, which calls for regular replacement of the timing belt to prevent costly engine damage. But the G10 valve-train is a non-interference design, which means that the open valves cannot ever hit the pistons. So if your timing belt breaks, the valves will stop but cannot come in contact with a moving piston. This prevents bent valves and damaged pistons.
These engines last a long time, and are simple to fix. When determining the health of a G10, the first order of business is a
. Think of this as a stethoscope for your engine. With high numbers across the board, you have a healthy engine. Any remaining problems will be related to fuel delivery or the electrical system. [is this a safe statement?] Low numbers in one or more cylinders indicates a specific problem, like a burnt valve. Low numbers across the board means the engine will need a rebuild soon.
The timing needs to be set properly - See how
If you have a pre-1996 Metro and the "Check Engine" light on and would like to find out why, you need to access your fuse panel and look for the diagnostic port. Insert a spare fuse into the port and then turn your key to the "ON" position. The check engine light will then blink a 2 digit code over and over. It may display more than one code also. Simply count the flashes for the code. See the codes
Because of its simplicity and small size, you can
this engine very easily. Many of the members here have done this on their own, and there are how-to guides posted to make this even easier. It is very straightforward, even if you are not mechanically minded. We are here to help you.
is a list of engine related threads.
How To - Compression Test
engine diagnose guide
Check Engine Light Guide
1.0L Head Repair Guide
engine rebuild guide
Bottom End Rebuild Guide
engine rebuild guide
How To: Pull a G10
engine remove guide
Detailed 1.0L head rebuild guide
Head gasket warning/Oil pan gaskets
Engine torque specs
Rounded/Stripped head bolt removal
Crank Seal - How To
Crank Sprocket bolt removal
Timing Belt / Camshaft / Distributor
Timing Belt Replacement Guide
engine timing replace guide
engine timing electrical guide
Checking Timing on a 94 Xfi
Camshaft Swap - How To
How To: Replace a leaking distributor O-Ring
how to: proper tools for egr cleaning...
Metro EGR System
Replacing alternator bearing (video)
How To Remove A Stubborn Oil FIlter.
How to "Fix" a Mystery Coolant Leak
How to Save an Exhaust Manifold
g10 piston rings
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