1998 Ford F-150 truck won['t start

Tiny
JOCOLE33
  • MEMBER
  • 1998 FORD F-150
  • 6 CYL
  • 4WD
  • MANUAL
  • 149,500 MILES
My truck won't start- battery and all cables have been replaced- starter checked out fine- three times) It used to click when trying to start, we replaced the starter relay- now it just makes a loud thunk when trying to start. It has alternated between the two sounds in the past.
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Friday, December 5th, 2008 AT 1:15 PM

3 Replies

Tiny
DAVE H
  • EXPERT
Try cranking engine a couple of times by hand .. with wrench on crank pulley?? is it free ?

ENGINE DOES NOT CRANK OR RELAY CLICKS
Voltage To Starter Relay

Using DVOM, check voltage between starter relay terminal No. 30 and ground. See Fig. 1 . If 12.5 or more volts exists, go to next step. If less than 12.5 volts exists, repair or replace battery to starter relay cable. Recheck system operation.
Check Voltage To Starter Motor Solenoid

Using DVOM, check voltage between starter motor solenoid "B" terminal and ground. If 12.5 or more volts exists, go to next step. If less than 12.5 volts exist, repair Red wire between battery and starter solenoid. Clean and tighten battery terminal connections. Recheck system operation.
Manually Jump Starter Motor

Using jumper wire, connect one end to positive battery terminal and with other end, momentarily touch starter solenoid "S" terminal (Black wire). If solenoid engages, go to next step. If solenoid does not engage, replace starter solenoid. Recheck system operation.
Check Starter Motor

Using jumper wire, connect one end to positive battery terminal and with other end, momentarily touch starter solenoid "M" terminal. If starter engages, go to next step. If starter does not engage, replace starter motor. See STARTER MOTOR under REMOVAL & INSTALLATION. Recheck system operation.
Check Continuity Of Circuit Between Starter Relay &

MD11Starter Solenoid Disconnect starter relay. Disconnect starter motor solenoid relay switch. Using DVOM, measure resistance of Black wire between starter relay and starter solenoid. If resistance is less than 5 ohms, replace starter relay. If resistance is more than 5 ohms, repair high resistance in Black wire between starter relay and starter solenoid. Recheck system operation.
Fig. 1: Identifying Starter Relay Terminals
Courtesy of FORD MOTOR CO.


http://www.2carpros.com/forum/automotive_pictures/266999_sol_1.jpg

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Friday, December 5th, 2008 AT 1:39 PM
Tiny
JOCOLE33
  • MEMBER
Also, am unsure if it's related or not, but the door chime dings whenever the door is open even though key isn't in ignition? I have replaced starter relay twice as well.
If I can't free engine by hand, then what?
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Friday, December 5th, 2008 AT 3:18 PM
Tiny
DAVE H
  • EXPERT
That could be related .. if the ignition switch is sticking .. the contacts inside the switch ... it may be not connecting the live to the starter motor correctly ..

IGNITION SWITCH
To inspect ignition switch for mechanical operation, rotate lock cylinder through all switch positions. Lock cylinder should not bind, and should return from START to RUN position without assistance. Replace ignition switch as necessary.
To test electrical function of ignition switch, disconnect ignition switch connector. Check continuity between specified switch terminals using a self-powered test light or ohmmeter. See Fig. 2 . See IGNITION SWITCH CONTINUITY table. If continuity is not as specified, replace ignition switch.
IGNITION SWITCH CONTINUITY
Continuity Between TerminalsSwitch Position
STA & B4...................Start
GND & P2...................Start
B5 & I1.......................Run
B1 & A1......................Run
B5 & A1......................ACC
B3 & A3......................Run
B2 & A2......................Run
B4 & A4......................Run

Fig. 2: Identifying Ignition Switch Harness Connector Terminals


http://www.2carpros.com/forum/automotive_pictures/266999_term_1.jpg



the engine should crank over by hand .. it will be easier if you take the plugs out ... ...if it doesn't crank by hand .. we're in big trouble .. the engine is seized somehow ??
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Friday, December 5th, 2008 AT 4:03 PM

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