Shuts off over 1500 RPM's

CRAIG STURTEVANT

MEMBER
1996 FORD F-350
6.9L
V8
4WD
AUTOMATIC
100,000 MILES

This is just a plow truck. The engine is a 460. It goes for about one hour or so and shuts off with no warning. Let it cool off starts up like always. No codes at the Ford dealer. One time I was parking it and raced the engine and it would shut off the minute it hit 1500 rpm's on the tachometer let up the gas and it would stay running. Every time it stop running it is working hard over 1500 rpm's. The Ford dealer ship has given up. I am desperately needing help.

Thursday, January 11th, 2018 AT 10:43 AM

7 Replies

KEN L

MASTER CERTIFIED MECHANIC
54,137 POSTS

Hello,

This sounds like you have an ignition switch that has worn out. Through the years the contacts become heated and then they stop working after a short time.

Here is a guide to help you replace the switch and the wiring diagrams to help you confirm the failure:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Check out the diagrams (below).

Please let us know what you find.

Cheers, Ken

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Friday, January 12th, 2018 AT 2:57 PM

CRAIG STURTEVANT

MEMBER
4 POSTS

Just to verify are you saying the key switch That would make it just shut off. And have to wait and let it cool off to start again. The Ford dealer through up there hand today and said to take it home and good luck. What about I think they said IPS. They just want to throw parts at it.

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Friday, January 12th, 2018 AT 3:18 PM

KEN L

MASTER CERTIFIED MECHANIC
54,137 POSTS

Yes, classic ignition switch 80% sure. You can test through the switch to confirm when the engine stalls the power will stop coming through the switch at it will be warm.

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Friday, January 12th, 2018 AT 5:28 PM

CRAIG STURTEVANT