Need help, truck died while driving 96 3500 7.4

[99k3500]

Will check tomorrow after work, haven't pulled dizzy cap yet, wanted to check other options. Could be injector issue, but there damn near new, replaced them with bosch upgrades not long ago.

Where did you get your new injectors from, I’ve been looking at replacing mine

 

[Jeeperguy]

Where did you get your new injectors from, I’ve been looking at replacing mine

Five0motorsports,,,, bosch injector upgrade for 7.4. Was a little less than $500. Good warranty, Good reviews and I also know others with the same motor and injector upgrade. Pretty easy, 1 day job and was a very noticable upgrade, truck starts instantly and smooth as ever!

 

[Jeeperguy]

I had a distributor cap fail in similar way. Just died and would not start except for occasional back fire. Still had some spark

Exactly what it was!

 

[yevgenievich]

Exactly what it was!

I have a spare cap in the glove box now, along with the ignition module.
At least until I change to individual coils.

 

[Tomcat58]

In my younger days my daddy used to say... Son the problem is one of three things. Fuel, Electrical or mechanical. No go play the game of process of illumination. I always did the easy checks first. Pull a plug and look at it. Is it dry to the bone or wet with fuel ? Dry fuel not getting to the engine. Wet fuels getting there but is it real wet ? fuel ok ! Heck sense your there now place the end of the spark plug wire 1/8 from a ground. Crank the engine over a few times and check for spark. No spark ? its electrical or mechanical problem like the distributor. Put the plug and wire back on and pull the distributor cap. Turn it over .. rotor turns or not ? Now I could go on and on but I had a 96 3500hd 7.4 that died like yours. one minute ran perfect next nothing. When simple checks don't show the problem I always go old school.. Take a a cylinder compression test. Which I did and waaaammm number 3 had a problem.

Turns out I bent 2 push rods at 35mph (2000 rpm) What the heck ? Well turns out that a few years of TBI 7.4 had issues of throwing push rods. Google it for details. Good luck fixing your big block !!!

 

[Jeeperguy]

In my younger days my daddy used to say... Son the problem is one of three things. Fuel, Electrical or mechanical. No go play the game of process of illumination. I always did the easy checks first. Pull a plug and look at it. Is it dry to the bone or wet with fuel ? Dry fuel not getting to the engine. Wet fuels getting there but is it real wet ? fuel ok ! Heck sense your there now place the end of the spark plug wire 1/8 from a ground. Crank the engine over a few times and check for spark. No spark ? its electrical or mechanical problem like the distributor. Put the plug and wire back on and pull the distributor cap. Turn it over .. rotor turns or not ? Now I could go on and on but I had a 96 3500hd 7.4 that died like yours. one minute ran perfect next nothing. When simple checks don't show the problem I always go old school.. Take a a cylinder compression test. Which I did and waaaammm number 3 had a problem.

Turns out I bent 2 push rods at 35mph (2000 rpm) What the heck ? Well turns out that a few years of TBI 7.4 had issues of throwing push rods. Google it for details. Good luck fixing your big block !!!

Already fixed, process of elimination. Had spark, Had fuel. I checked spark at plugs before pulling dizzy cap, so it looked like it should've started, but because the rotor was pretty much just bouncing around it still threw a spark, but out of time. Until actually pulling the cap did I see it wasnt even attached to dizzy.

 

[Jeeperguy]

Wow, wtf. Exactly the same scenario. Went and got coffee, and almost in the exact same location the truck just died. Maybe 2 blocks further than last time, towed it home again with my ford (i know) and pulled cap and found rotor was missing 1 screw and the brass contact on top broke off. Now after further fawking with it, I found that one of the screw holes in distributor where the rotor sits on top of is stripped out and neve got tight on one side of rotor. It would back out and,,,, there you go! So I'm hoping to run a m3 tap (i think) in it and some loctite andnbe good, or go next size up, or replace distributor all together.

 

[Schurkey]

If I were you, I'd be checking the distributor bushings very carefully.

Good possibility that the shaft is wobbling enough to smack the rotor into the cap, and the rotor breaks before the cap does.

 

[Jeeperguy]

If I were you, I'd be checking the distributor bushings very carefully.

Good possibility that the shaft is wobbling enough to smack the rotor into the cap, and the rotor breaks before the cap does.

No, distributor is good, no play, just fawked up fine threads on the metal base plate that the rotor sits on. Gonna loctite them, should be good.

 

[yevgenievich]

I had to fix one with a bad thread. And the rotor holder was actually rotated off the right place as well due to forces.(should be checked as it is just pressed in). Reset the metal bracket and tapped both holes for a bit larger screws.

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