BGS technic 74355 Manual De Instrucciones página 8

TEST RESULTS
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On a normal cylinder, the gauge needle should travel up the scale on each compression stroke
until it reaches peak value. All cylinders should indicate a pressure that is within the vehicle
manufacturer's specifications, and the reading should not vary by more than 10% from cylinder to
cylinder.
•
If the gauge needle does not travel up the scale or if it remains at the same value for several
strokes and then starts to climb, the problem could be a valve sticking.
•
If the compression reading is considerably higher than the vehicle manufacturer's specification,
the problem may be carbon build-up in the cylinder. It may also indicate that either the piston, or
the cylinder head, has been modified.
•
If the readings on two adjacent cylinders differ greatly, the problem may be a cracked cylinder
head or a blown head gasket. Under these conditions, both coolant and oil can be in both
cylinders.
•
If the readings are low, or vary widely between cylinders, pour a teaspoon of SAE 30 oil into each
cylinder and retest them. If the readings increase considerably, the problem may be poorly
seated, or worn, piston rings. If the readings remain about the same, the valves and/or
associated components may be the problem. A burned or damaged piston may also cause the
same results.
TEST COMPLETION
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Clean, re-gap and reinstall the spark plugs in the same order in which they were removed, or
install new spark plugs. Reconnect each spark plug wire to the plug it was connected to prior to
removal.
•
Return the throttle plates to the closed position.
IMPORTANT: After test, failure to return the throttle plates to the closed position before starting
the engine can cause serious damage to the engine.
•
Reconnect the disconnected ignition system wiring.
FUEL PRESSURE TEST
RELIEVING FUEL SYSTEM PRESSURE
NOTE! The following instructions are intended as a guide only. Always adhere to manufacturer's
procedures for relieving system pressure.
•
Before disconnecting the fuel lines to connect adaptors and pressure gauge to fuel system, the
fuel system pressure must be relieved, this will prevent fuel spraying when a joint is
disconnected.
•
Switch off ignition, loosen the fuel tank cap to relieve tank pressure, then re-tighten.
•
To relieve fuel pressure, it is necessary to prevent the fuel pump operating, whilst still allowing
both injection and ignition systems to operate.
•
The procedure may simply require the fuel pump relay, fuse or electrical supply to be
disconnected; some models have two fuel pumps, make sure both are disabled.
•
Once pump(s) is/are disabled, run the engine until it stalls, and then crank over short times after it
has stalled. On some electronic fuel injection systems, removing the fuel pump fuse disables both
the fuel pump and the injectors.
•
WARNING! DO NOT assume that pressure in the fuel system has been relieved. When
disconnecting, wrap a cloth around the fuel line fitting to absorb any fuel leakage.
CONNECTION AND USAGE
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With the engine off and the fuel system pressure relieved, install the correct adaptor into the fuel
system at the point to be tested and connect to the quick coupler on the gauge hose ensuring the
locking collar is in position.
•
NOTE! Use a cloth around the fittings to absorb any fuel.
•
Re-connect the fuel pump(s).
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Start engine and allow to idle.
•
Read the fuel pressure on the gauge and compare to the manufacturer's specification.
•
Turn off the engine.
•
Remove the tester and adaptors from the fuel line.
•
Restore fuel line to original condition, restart the engine and check the system for leaks.
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