Will not stay running?

DANIEL JENNIFER PIERCE

MEMBER
1979 JEEP CJ7
4.3L
6 CYL
4WD
MANUAL
79,678 MILES

I bought a new 79 cj7. I drove it home a few weeks ago and it did fine. Next day I took it out for a spin, and it shut off on me initially thought ran out of fuel. Have put 7 gallons in it and changed fuel filter. Still not starting it cranks and fires for a second but when you release key it doesn't stay running. Changed ignition module same results.

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6 Replies

KEN L

MASTER CERTIFIED MECHANIC
48,360 POSTS

Thanks for the video and images. Will it stay running if you hold your foot on the throttle slightly? It sounds like either the carburetor has a clogged idle circuit or there is a vacuum leak. I would start by removing the EGR valve and running this test in the video below.

https://youtu.be/DqUCbbKdWf4

If it passes have a helper hold the RPMs up slightly and use this guide to look for vacuum leak when the engine is cold:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please go over these guides and get back to me.

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Saturday, February 18th, 2023 AT 5:15 PM

DANIEL JENNIFER PIERCE

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4 POSTS

I actually messed with it today. I have 0-voltage at resistor when key is in run position. I used a jumper wire from battery to resistor headed to coil and it fires right up. Remove the jumper wire and he shuts down.

Not getting any juice from ignition switch. I've got a new ignition switch coming.

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Saturday, February 18th, 2023 AT 6:04 PM

KEN L

MASTER CERTIFIED MECHANIC
48,360 POSTS

Good find on that, please let me know if the switch fixes it.

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Sunday, February 19th, 2023 AT 11:09 AM

DANIEL JENNIFER PIERCE

MEMBER
4 POSTS

Well, I got to messing around in fuse box and the 30amp fuse for coil was blown so I replaced that, and she fired like a champ last night. But today driving it a little the starter gear is not retracting like it should. It does retract it I clutch and put it in gear. But going down the road every once in a while it sounds like that starter gear is protruding just a bit and occasionally engages with flywheel. Any idea starter or solenoid?

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Sunday, February 19th, 2023 AT 11:56 AM

KEN L