Generac Power Systems XT-EFI Series User Manual

Table of Contents
Diagnostic Repair Manual v
Safety ........................................................................ ii
Read This Manual Thoroughly .................................. ii
Replacement Parts ................................................... ii
Rotor and Stator Resistance Tables ........................ iii
Section 1 Brushless Capacitor Excitation..................1
Introduction ...............................................................1
Stator Assembly ........................................................1
Rotor Assembly ........................................................1
Operation ..................................................................2
Troubleshooting Flowcharts ......................................3
If Problem Involves AC Output.................................. 3
Problem 1 – Generator Produces Zero Voltage
or Residual Voltage .................................................. 3
Problem 2 – Voltage & Frequency Are Both
High or Low............................................................... 4
Problem 3 – Excessive Voltage/Frequency
Droop When Load is Applied .................................... 4
Problem 4 – Generator Produces High Voltage
at No-Load ................................................................ 4
Section 2 Direct Excitation (Brush Type)....................5
Introduction ...............................................................5
Stator Assembly ........................................................5
Brush Holder and Brushes ........................................5
Voltage Regulator .....................................................5
Operation ..................................................................5
Troubleshooting Flowcharts ......................................7
If Problem Involves AC Output (Brush Type)............ 7
Problem 5 – Generator Produces Zero Voltage or
Residual Voltage....................................................... 7
Problem 6 – Voltage & Frequency Are Both
High or Low............................................................... 8
Problem 7 – Excessive Voltage/Frequency
Droop When Load is Applied .................................... 8
Problem 8 – Generator Produces High Voltage
at No-Load ................................................................ 8
Section 3 AC Diagnostic Tests ....................................9
Test 1 – Check No-Load Voltage and Frequency .....9
Test 2 – Check Main Circuit Breaker ........................9
Test 3 – Check Continuity of Receptacle Panel ........9
Test 4 – Fixed Excitation Test/Rotor Amp
Draw Test ................................................................10
Test 5 – Field Flash Alternator ................................12
Test 6 – Check Capacitor .......................................13
Test 7 – Test Brushless DPE Windings ..................13
Test 8 – Test Brushless Stator Windings ................14
Test 9 – Test Brushed Stator Windings ..................14
Test 10 – Check Load Voltage & Frequency ..........14
Test 11 – Check Load Watts & Amperage .............14
Test 12 – Adjust Voltage Regulator ........................15
Test 13 – Voltage Changeover Switch
120/240 Position .....................................................15
Section 4 EFI Engine Control Diagnostic Tests.......17
Basic EFI Theory ....................................................17
Basic Open-Loop Theory ........................................17
Engine Requirements .............................................17
Fuel System ............................................................17
Air Metering and Measurement ..............................18
Sensor Inputs ..........................................................18
Basic Operation ......................................................18
EFI Fault Code Diagnostics ....................................19
Section 5 Engine Diagnostic Tests ...........................21
Diagnostic Flow Charts ...........................................21
Problem 9 – Recoil Cord Will Not Pull
(208/389/420/459cc Engines)................................. 21
Problem 10 – Engine Starts Hard and Runs
Rough (208/389/420cc Non-EFI Engines).............. 21
Problem 11 – Engine Turns Over But Will
Not Start (208/389/420cc Non-EFI Engines) .......... 22
Problem 12 – Engine “Hunts” / Erratic Idle
(208/389/420cc Non-EFI Engines) ......................... 22
Problem 13 – Engine Will Not Crank
(220/410/530cc Engines with Electric Start) ........... 23
Problem 14 – Recoil Cord Will Not Pull
(If So Equipped) (220/410/459/530cc Engines)...... 23
Problem 15 – Engine Cranks But Will Not Start
(220/410/530cc Non-EFI Engines) ......................... 24
Problem 16 – Engine Starts Hard and Runs
Rough (220/410/530cc Non-EFI Engines).............. 25
Problem 17 – Engine Starts Then Shuts Down
(220/410/530cc Non-EFI Engines) ......................... 25
Problem 18 – Battery Will Not Charge
(220/410/459/530cc Engines)................................. 25
Problem 19 – Engine “Hunts” / Erratic Idle
(220/410/530cc Non-EFI Engines) ......................... 26
Problem 20 – Unit Will Not Idle
(220/410/426/530cc Non-EFI Engines) .................. 26
Problem 21 – Unit Will Not Come Off Idle
(220/410/426/530cc Non-EFI Engines) .................. 26
Introduction .............................................................27
Test 14 – Check Fuse .............................................27
Test 15 – Check Battery and Cables ......................27

Generac Power Systems XT-EFI Series Specifications

General

Brand	Generac Power Systems
Model	XT-EFI Series
Category	Portable Generator
Language	English