Advertisement
3.7
Remove the air filter and set the throttle plates to the wide open position, taking care not to damage
the linkage or throttle components.
IMPORTANT: After test, failure to return the throttle plates to the closed position before starting
the engine can cause serious damage to the engine.
3.8
Disconnect the ignition system, following the manufacturer's recommendations in the vehicle servicing
manual.
3.9
Select the spark plug adaptor required for the vehicle. Screw the adaptor to the hose. Screw the spark
plug adaptor and hose assembly into a spark plug well. Hand tighten only. DO NOT use a wrench.
Refer to Fig.2.
3.10
Connect the coupling on the gauge to the hose. Ensure the coupling is fully engaged.
3.11
Crank the engine for at least five compression strokes, or until the pressure reading on the gauge
stops rising.
3.12
Record the compression reading, then push the side release valve to relieve the pressure.
3.13
Repeat the test and record the reading. Relieve the pressure and remove the hose and adaptor from
the spark plug well.
3.14
Repeat for the remainder of the cylinders.
3.15
You may also connect one of the Push On Connectors straight to the gauge coupling to aid quick
installation. Select either the straight or angled stem for easiest access.
4.
TEST RESULTS
4.1
Gauge Readings
4.2
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.
4.3
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.
4.4
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.
4.5
If a reading on two adjacent cylinders is 20psi (or more) lower than the other cylinders, the problem
may be a cracked cylinder head or defective main gasket. Under these conditions, both coolant and oil
may be found in both cylinders.
4.6
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.
5.
COMPLETION OF TESTS
5.1
Clean, re-gap and reinstall the
spark plugs in the same order in
which they were removed, or
install new spark plugs.
5.2
Reconnect each spark plug wire
to the plug it was connected to
prior to removal.
5.3
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.
5.4
Reconnect the ignition system
wiring disconnected in paragraph 3.8.
NOTE: It is our policy to continually improve products and as such we reserve the right to alter data, specifications and component parts without prior notice.
IMPORTANT: No liability is accepted for incorrect use of product.
WARRANTY: Guarantee is 12 months from purchase date, proof of which will be required for any claim.
INFORMATION: For a copy of our latest catalogue and promotions call us on 01284 757525 and leave your full name and address, including postcode.
Ø63mm Gauge
Push On Connectors
Sole UK Distributor,
Sealey Group,
Bury St. Edmunds, Suffolk.
10mm
12mm
14mm
18mm
01284 757500
W e b
sales@sealey.co.uk
01284 703534
e-mail
CT955.V2
Hose
www.sealey.co.uk
Issue No: 1 - 30/09/08
Advertisement
