Build Mississippi Delta Beast - 1974 FJ-40 Rescue and Rehabilitation

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wngrog said:
150 mile test loop today with this great cool snap we are having. No chance I could have done this the last two weeks here in Mississippi. Nothing fell off. I’ll call that a win.

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Love this build Nolen! It's Mississippi cousin says hi!

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Bringing this thing back from the dead.

Cliff notes

The truck would run great. Long hard pulls. No problems.

Once it got good and hot though the Sniper would over fuel when you came to a stop.

I thought it was a bad Sniper. So I changed Snipers.

Same issue.

3 intakes later I took off the Snipers and reworked it to use a carburetor.

Same.

Gave up and let Shaw take a shot at it.

Same.

I tabled it. Sent a good carburetor to @FJ40Jim and commenced to building an FJ60, a FJ40, and and FJ45 in the last 4 months. I’ve got a break for a couple days so I’m pulling the head off and taking it to Mosley to see if it’s cracked somewhere causing the stalling at full operation heat.

If nothing is wrong with it I’m pulling the motor.

It’s been sitting for 4 months and it fired right up though…..more later.

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All the Sniper data reads showed it was getting a vacuum leak and the Sniper was over fueling to compensate.

None of the other External fixes worked. Has to be internal.

The fact it did it with 2 snipers and a carburetor points that way at least
White Stripe said:
What makes you say it's overfueling?
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So a vacuum leak in a carb’d system causes more fuel flow so the engine pukes. I’ll have to think about that a bit. Thought it was a leaning effect.
 
middlecalf said:
So a vacuum leak in a carb’d system causes more fuel flow so the engine pukes. I’ll have to think about that a bit. Thought it was a leaning effect.
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Man look. Don’t take this as me knowing what’s what because I don’t.

The Holley guys said that during the data logs…..

No issues for 30 minutes stop and go driving.

Get in the road. 15-20 min then let off the gas and the system showed massive vacuum leak. Sniper dumped fuel to compensate.

Truck dies. Hard start and gas smoke from the exhaust when it does start.

Dies every stop until you park it and it cools.
 
Not chasing the Sniper stuff, I have no clue as to what the Sniper computer does with whatever sensed data it gets from whatever sensors. I was focused on the carb scenario, which you said had the same result (over fueling which I interpreted as rich) as the Sniper all the while being a dumb system that works solely on vacuum. Your thought of the rich issue (probably from the wacked out AFR reading from the Sniper data) being a vacuum leak is counter to the typical vacuum leak symptom in the carb’d world, which is a lean condition. So they might not be related. In any case, Mosely will figure it out.

And I follow most of what you do on mud because you do know what you’re doing. FWTW.
 
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On this truck I don’t know what im doing.

I’ve passed it to some good mechanics. They also came up zeros.

Something internal is off. Gotta find it. Maybe I’m explaining wrong
 
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