VISUAL INSPECTION
Visually inspect all electrical wiring. Look for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and not pinched or cut. If necessary, see appropriate VACUUM DIAGRAMS article to verify routing and connections. Inspect air induction system for possible vacuum leaks.
- «VACUUM DIAGRAMS»(ref-19754) (for "C" & "K" Series)
- «VACUUM DIAGRAMS»(ref-19758) (For "G" & "P" Series)
A-3, NO-START DIAGNOSIS
Note. For diesel information, see appropriate G - DIESEL TESTS W/ CODES article below and TESTS W/O CODES - 6.5L DIESEL article in the ENGINE PERFORMANCE section.
- «TESTS W/CODES - 6.5L DIESEL»(ref-19760) (for "C" & "K" Series)
- «TESTS W/CODES - 6.5L DIESEL»(ref-19761) (for "G" & "P" Series)
FUEL PUMP FLOW TEST
- Disconnect fuel line at fuel filter inlet. Disconnect fuel injection pump electric shut-off solenoid wire (Pink).
- Crank engine 15 seconds. If fuel pump does not supply approximately 1/2 pint of fuel in 15 seconds, go to «FUEL SYSTEM PRESSURE TEST»(ref-19764-S27484112172001110200000) .
FUEL SYSTEM PRESSURE TEST
| CAUTION | Begin fuel system trouble shooting and diagnosis with fuel system pressure test. Relieve fuel system pressure before disconnecting any components or installing fuel pressure gauge. See FUEL SYSTEM PRESSURE RELIEF under A-7, BASIC FUEL SYSTEM CHECKS (GASOLINE). |
- Turn engine off. Disconnect fuel line at inlet to fuel filter assembly. Install low pressure fuel gauge to fuel line.
- Crank or run engine 10-15 seconds. If fuel pressure is not 5.8-8.7 psi (.41-.61 kg/cm 2 ), check fuel lines and fuel tank sending unit for restriction. If fuel lines and sending unit are okay, replace fuel pump.
DIAGNOSTIC CIRCUIT CHECK
Note. 6.5L with light duty emissions is equipped with a self-diagnostic system. For information on diagnostic system check and retrieving codes, see appropriate G - 6.5L DIESEL TESTS W/ CODES article in the ENGINE PERFORMANCE section below.
- «TESTS W/CODES - 6.5L DIESEL»(ref-19760) (for "C" & "K" Series)
- «TESTS W/CODES - 6.5L DIESEL»(ref-19761) (for "G" & "P" Series)
Preliminary Inspection
- Check all vacuum hoses for incorrect routing, restrictions, cuts and other damage. Inspect hoses beneath air cleaner assembly and other engine components.
- Inspect all wires in engine compartment for correct and good connections. Also check wires for pinched or chaffed spots, as well as contact with sharp edges or exhaust manifolds. (Scheme 409)or (Scheme 410).
- Perform preliminary inspection carefully and thoroughly. A thorough inspection can often identify cause of problem without further diagnosis.
Diagnostic Procedure
- Ensure all engine systems not related to Diesel Electronic Control (DEC) system are operating properly. DO NOT proceed with testing unless all problems not related to DEC system have been repaired. DEC system diagnosis should always begin with DIAGNOSTIC SYSTEM CHECK chart under DIAGNOSTIC CHARTS in appropriate G - 6.5L DIESEL TESTS W/ CODES article in the ENGINE PERFORMANCE section below. Performing this check determines whether DEC system and ECM are working properly. «TESTS W/CODES - 6.5L DIESEL»(ref-19760) (for "C" & "K" Series) «TESTS W/CODES - 6.5L DIESEL»(ref-19761) (for "G" & "P" Series)
- If trouble codes (other than Code 12) are displayed, determine whether codes are hard or intermittent trouble codes. A hard code remains until code-setting condition is repaired. Hard codes cause Malfunction Indicator Light (MIL) to come on.
- An intermittent code does not reset itself and is not present when vehicle is repaired. An intermittent code is often caused by loose connections. MIL goes out 10 seconds after fault goes away.
