GxT Ferret 71 User Manual

OPERATOR’S MANUAL

Fuel Injector Probe 71

FEATURES

To Connect to the Fuel Injector

1. Connect the Inductive Pickup around a single drive
wire going to an injector or bank of injectors. Confirm
the pickup is connected properly by selecting the Drive
Time function. If Drive time is full scale at Idle, the
Pickup is on Backwards.

Measurements

1. Peak Amps is the peak current driving the injector. It
is regulated by the driver. Typical peak readings are
from 1 to 4 amps for a current regulated injector driver,
and about 1 amp for a resistance limited injector driver.
Peak Amps automatically selects the proper range.
Be sure to note which range LED is active.

2. Build Time, is the time it takes the amperage to reach
its maximum. Build Time is affected by the solenoid
and pintle movement. Shorter Build Time can be caused
by a solenoid winding short or an injector that is stuck.
Longer build time could be from a bad driver or wire
connection. Build Time is read on the upper scale.

3. Drive Time is the time the injector is actively driven.
Use momentary wide open throttle to see the Min and
Max readings. Drive Time is read on the lower scale.

Analysis of Test Results

In general, a difference of 1 amp between injector banks
on resistance regulated injectors indicates that one or more
injectors is faulty in the bank with the higher amperage
draw. In a current regulated system, look for build time to
be longer on the bank with an open or high resistance
injector. Build will be shorter on the bank with a shorted
injector.

Test Fuel Injectors without
piercing wires or backprobing
connectors. Connect to an
individual injector or a bank of
injectors inductively.

Use a LabScope to view the fuel
injector pattern.

20 segment bar graph displays
Peak Amps, Build Time or Drive
Time at the press of a button.

Easily locate open or shorted
injectors by using current
ramping measurements.

Powered by a 9 Volt battery.

3 Year Limited Warranty

www.ferretinstruments.com

Using the Fuel Injector Probe with a Labscope

The 71 sends a signal that is scaled at .1 volts (or 100mV)
per amp detected. A 4 amp peak will appear 0.4 volts high
on the labscope. Use a BNC Cable with a BNC to Banana
Adapter (like Ferret P/N W090-10) to adapt the 71 to work
on most labscopes or graphing multimeters.

Technical Support

For additional information or technical assistance, please
contact Ferret Instruments at [phone] or
www.ferretinstruments.com.

SAFETY PRECAUTIONS

• Always wear safety glasses, or other eye protection when testing vehicles. Be extra careful
near batteries and moving parts.

• Battery gas is highly explosive.
a. If a battery explodes, flush the acid away from person's skin with generous amounts of

water. Follow up with a neutralizing solution of baking soda and then more water.
Medical treatment for acid burns may be necessary.

Treat clothing, vehicle parts, and equipment similarly. Any acid traces inside equipment
must be removed by generous rinsing. Dry off equipment afterwards and place in a
warm 50° C (120° F) oven until thoroughly dry.

b. Never use a wrench on the ungrounded battery terminal until the grounded one has

been disconnected. Contact between the vehicle body metal and the "hot" terminal can

cause sparks to ignite gas or even weld tools into a battery short circuit.
c. Keep the space around a battery well ventilated.
d. Do not make sparks or allow flames near batteries.

• Before working on a vehicle, set the brakes and block the wheels. Beware of automatic
parking brake releases.

• Keep your work area well ventilated and free of exhaust. Engine exhaust contains deadly
poisons.

• Avoid electrical shocks caused by getting too close to live ignition wires or touching the coil
TACH terminal. A person's reaction near a running engine can be more damaging than the
shock.

• Keep spark producing devices at least 0.5m (18") above the floor to reduce the hazard of
igniting gasoline vapor.

• Do not let test leads wind up in a fan or pulley. Route leads away.

• Remove finger rings and metal wristbands. They can short terminals and become very hot
from electric current.

FERRET INSTRUMENTS, INC. of Cheboygan Michigan, warrants to the original purchaser that any products manufactured
or supplied by Ferret Instruments, Inc. are free from defects in materials and workmanship for a period of three years from
date of purchase. Our sole obligation for a product within the above warranties will be to repair or replace, at our option, any
defective parts and return the product to the sender within the U.S.A., shipping prepaid, if it is sent to our Repair Depart­ment shipping prepaid and accompanied by proof of purchase. The above warranty is extended for the flashtubes in timing
lights which are within five years of the date of manufacture.

A Ferret product less than five years old according to the date of manufacture, and which is returned with transportation
charges prepaid to: Ferret Instruments, Inc., Repair Department, 1310 Higgins Drive, Cheboygan, MI 49721, will be
repaired or replaced, at factory option, for a service charge not to exceed 40% of the latest factory suggested user price;
plus return transportation charges and insurance. If the product has been discontinued, the nearest equivalent product may
be substituted.

FERRET INSTRUMENTS LIMITED PRODUCT WARRANTY

EXTENDED SERVICE POLICY

This Warranty and Extended Service Policy do not apply to products which have been altered outside the factory; or
repaired by anyone other than the factory or its authorized service centers; or which have been damaged from accidents,
negligence, or abuse; or have been used differently than described in the printed instructions. Please note that wear and
tear on leads and replacement of consumable (paper, oxygen sensors, Nox Sensors, etc.) items, is not covered by warranty.

Ferret Instruments, Inc.'s sole liability and buyer's exclusive remedy is limited to repair or replacement of the product as
stated in the Limited Product Warranty and the Extended Service Policy. THERE ARE NO OTHER WARRANTIES EX­PRESSED OR IMPLIED INCLUDING THOSE OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
AND FERRET INSTRUMENTS, INC. SHALL NOT BE LIABLE FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES ARIS­ING FROM THE SALE OR USE OF THE PRODUCT.

Some states do not allow limitations on the length of implied warranties nor exclusion or limitations of incidental or conse­quential damages, so that the above limitations and/or exclusion may not apply to you. This warranty gives you specific
legal rights and you may also have other rights which may vary from state to state.