no spark

1994 FORD F-150

1,234,567,890 MILES • 5.8L • V8 • 2WD • AUTOMATIC

BIGGUY7180

MEMBER
2 POSTS

I have replaced the starter, the alternator, the distributor cap, rotor all relays, fuses, diode, the ignition coil and all three fuel pumps. However, when I go to turn it on and start it it only cranks and the fuel pump does not turn on. also I tested it for spark and there is no spark. Now also when I go to plug in my code reader all it does is flash the screen and turns all my fuel pump. Any idea what my problem could possibly be?

Sep 6, 2020 at 12:58 PM

KASEKENNY

✓Experienced Mechanic
18,907 POSTS

The fact that you have no spark points me towards the crank sensor. Your vehicle doesn't have a traditional crank sensor, it uses a hall effect sensor in the distributor that picks up the rotation of the distributor and based on when it passes the windows in the rotary vane it can tell what position the engine is in. This is what the PCM fires the injectors and spark plugs off of. If the PCM is not getting this signal or the PCM is faulty it will not fire the plugs or injectors.

I would recommend replacing the switch and rotary vane and retest.

Let me know what questions you have. Thanks

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Sep 6, 2020 at 1:12 PM

BIGGUY7180

MEMBER
2 POSTS

Thank you. I will try that.

Sep 7, 2020 at 9:30 AM

KASEKENNY

✓Experienced Mechanic
18,907 POSTS

Sounds good. Keep us posted. Thanks for the update.

Sep 7, 2020 at 12:57 PM

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