Equus 3614 User Manual

In this example, the highest compression reading is 140
psi. The lowest allowable reading would be 105 psi (140
psi X 0.75). The lowest reading (115 psi) is within the
allowable range.

DIAGNOSIS

1. On a normal cylinder, compression should increase

quickly and uniformly during each compression stroke
of the engine until a top (or peak) reading is reached.

2. If compression is low on the first stroke, builds up on
following strokes, but does not reach normal value, the
piston rings may be worn or leaking.

3. If compression is low on the first stroke and does not
increase on following strokes, leaking valves may be at
fault.

4. If the compression value is higher than the
manufacturer's specifications, carbon build-up may be
present in the cylinder or on the piston.

5. If compression readings on two adjacent cylinders are
20 pounds (or more) lower than the other cylinders, the
cylinder head gasket may be defective.

6. Recheck cylinders with low compression readings by
injecting approximately one tablespoon of medium­grade oil into each cylinder (through the spark plug
hole) and retesting. If compression readings increase,
worn, broken, or poorly seated piston rings are
indicated. If compression readings remain the same,
leaking or damaged valves may be at fault.

7. Before re-installation of spark plugs, clean and re-gap
all plugs. Reinstall spark plugs. Reconnect plug wires,
paying close attention to the cylinders from which they
were removed. Crossing spark plug wires will result in
rough running, misfiring, poor gas mileage, and may
cause damage to the catalytic converter or the engine.

8. Be sure to return the throttle plate to it's original
position, and reconnect the coil wire or reconnect the
ignition system primary connection.

NOTE: Periodically examine the valve core at the
14MM/18MM hose end for tightness using a standard
valve core tightening tool.

WARRANTY AND SERVICE

The Manufacturer warrants to the original purchaser that this unit is
free of defects in materials and workmanship under normal use and
maintenance for a period of one (1) year from the date of original
purchase. If the unit fails within the one (1) year period, it will be
repaired or replaced, at the Manufacturer's option, at no charge, when
returned prepaid to the Service Center with Proof of Purchase.
Installation labor is not covered under this warranty. The sales receipt
may be used for this purpose. This warranty does not apply to
damage caused by improper installation, accident, abuse, improper
voltage, fire, flood, lightning, or other acts of God, or if the product
was altered or repaired by anyone other than the Manufacturer's
Service Center. The Manufacturer, under no circumstances shall be
liable for any consequential damages for breach of any written
warranty of this unit. This warranty gives you specific legal rights, and
you may also have rights which vary from state to state. THIS
WARRANTY IS NOT TRANSFERABLE. For service, send (prepaid)
via U.P.S. (if possible) to manufacturer. Allow 3-4 weeks service time.
If you have any questions, please contact your local store, distributor
or the Manufacturer's Service Center. USA & Canada: (800) 544­4124; All others: [phone] (9:00-4:00, Monday-Friday PST);
FAX: [phone] (24 hr.)

OPERATING INSTRUCTIONS

KIT #3612 AND KIT #3614

KIT #3612 — COMPONENTS

150

180

120

90

8

6

60

4

2

0

30

kPa x 100

0

COMPRESSION

PSI

1

2

3

ITEM DESCRIPTION

1 Compression Gauge
2 14 mm Adapter
3 Spark Plug Hose Assembly (Rubber)
4 12 mm Adapter

KIT #3614 — COMPONENTS

150

120

10

90

60

30

1

2

4

3

ITEM DESCRIPTION

1 Compression Gauge
2 14 mm Adapter
3 12 mm Adapter
4 Spark Plug Hose Assembly (Braided Stainless Steel)
5 Direct Shaft
6 10 mm Adapter

8

6

4

2

0

kPa x 100

0

COMPRESSION

PSI

12

TESTER

10

TESTER

180

14

16
18

20

IEC

12

300

210

14

20

240

270

210

16

240

18

270

IEC

300

4

5

6



IEC 1997



IEC 1997

ABOUT THIS TOOL

The compression tester is a diagnostic tool which can help you
identify worn or damaged pistons, rings, valves and gaskets. A
compression check consists of measuring pressure at each
cylinder at cranking speed. ALWAYS perform a compression
check as part of the tune-up procedure.

SAFETY TIPS

1. Always wear safety eye protection.

2. Put transmission in “park” (for automatic) or “neutral”

(for manual). Set parking brake and block drive wheels.

3. Be sure to disable the ignition system to prevent the
car from starting (see TEST PROCEDURES, step 4).

4. This compression tester is designed for use on spark­ignited gasoline engines which do not exceed 250 psi. Use
of this tool for any other purpose may result in personal
injury, damage to the tool, or damage to your vehicle.

BEFORE TESTING

To ensure that compression readings are accurate,
perform the following pre-test procedures.

1. Make sure the vehicle battery is fully charged, and the
starter system is in good condition.

2. Warm up the engine until normal operating temper­ature is reached.

3. Be sure to remove ALL spark plugs before performing
the compression test.

4. On carbureted models, open choke plate to allow air
flow through the carburetor during testing (see TEST
PROCEDURES, step 3).

TEST PROCEDURES

CAUTION: Engine parts and surrounding areas will be hot.

1. Stop engine. Carefully disconnect all spark plug wires

from spark plugs. Number spark plug wires to aid in
proper reinstallation.

NOTE: To prevent damage to spark plug wires, be
sure to disconnect wires by first twisting then pulling on
the wire's boot and not on the wire itself.

2. Remove all spark plugs and place in order
corresponding to the cylinders from which they were
removed. (This procedure is used to associate cylinder
or compression problems by inspecting the condition
of a malfunctioning cylinder's spark plug.)

NOTE: To prevent thread damage on vehicles with
aluminum heads, wait approximately ten minutes before
removing spark plugs.

3. Locate the intake throttle plate (or carburetor throttle
plate). Secure the plate wide open for testing.

NOTE: You may also have an assistant help you by
holding the accelerator pedal down.

CAUTION: Be sure to return the throttle plate to it's origi­nal (closed) position after testing or before starting ve­hicle. Failure to comply can result in serious engine
damage.

4. Disable the ignition system:
NOTE: These are typical ignition systems. Refer to

your vehicle's service manual for additional information
on your vehicles ignition system and how to safely
disable it.

For electronic or conven­tional breaker point ignition
systems: Remove the high

HIGH TENSION
LEAD

CHASSIS GROUND

tension (coil) wire from the
distributor cap and connect to
a known good ground to avoid
spark discharge, or disconnect
coil primary connector.

For General Motors HEI
systems: Disconnect the

primary (or battery) con­nection from the distributor
cap and wrap with tape to
avoid accidental grouding.

PRIMARY
WIRE

5. Disconnect the spark plug hose from the compression

gauge. Screw the plug end of the hose into the spark
plug hole. HAND TIGHTEN ONLY.

NOTE: On engines with 14MM long
reach plugs, use the 14 MM
long reach adapter
included in kit. DO

150

180

120

210

10

90

12

8

14

6

16

240

60

4

18

2

270

20

0

30

kPa x 100

IEC

300

0

COMPRESSION

PSI

TESTER

NOT use adapter

in short reach
holes – it may hit
the top of the pis­ton and damage the
engine.

6. Connect the spark plug hose to
the compression gauge by
means of the "quick connect"
coupling. Make sure the coupling snaps into place.
This ensures the hose is "locked" into the gauge.

7. Crank the engine for at least
five compression strokes.

NOTE: Engine should be
cranked the same number of
strokes for each cylinder.

8. Record the reading from the
compression gauge for

60

30

120

90

0

150

10

8

6

4

2

0

kPa x 100

COMPRESSION

PSI

TESTER

180

210

12

14

16

240

18

270

20

IEC

300

RELEASE
VALVE

reference. Press the side
release valve to release
pressure from the gauge.
Disconnect the spark plug
hose from the compression
gauge. Connect the hose to
the next cylinder, and repeat
steps 5 through 8 (repeat for
each cylinder to be tested).

READING TEST RESULTS

The compression check identifies variations in com­pression between cylinders. Compression is considered
normal if the lowest compression reading is at least 75%
of the highest reading, as shown in the following example:

Cylinder Cyl 1 Cyl 2 Cyl 3 Cyl 4 Cyl 5 Cyl 6
Reading 130 125 140 125 130 115

(psi)