Join Date: Aug 2006
Location: Stuck in Indianapolis until the end of time
I belleve the FSM suggests warming up the engine to operating temps before the test.
Copied from the FSM
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Check engine oil level and add oil if necessary.
(2) Drive the vehicle until engine reaches normal
operating temperature. Select a route free from traf-
fic and other forms of congestion, observe all traffic
laws, and accelerate through the gears several times
(3) Disconnect and remove all ignition coils from
(4) Remove all spark plugs from engine. As spark
plugs are being removed, check electrodes for abnor-
mal firing indicators fouled, hot, oily, etc. Record cyl-
inder number of spark plug for future reference.
(5) Be sure throttle blade is fully open during the
(6) Insert compression gauge adaptor Special Tool
8116 or the equivalent, into the #1 spark plug hole in
cylinder head. Connect the 0–500 psi (Blue) pressure
transducer (Special Tool CH7059) with cable adap-
tors to the DRBIII
(7) Crank engine until maximum pressure is
reached on gage. Record this pressure as #1 cylinder
(8) Repeat the previous step for all remaining cyl-
(9) Compression should not be less than 689 kPa
(100 psi) and not vary more than 25 percent from cyl-
inder to cylinder
Last edited by tgs; 01-27-2016 at 10:10 AM.