383 Engine troubles! Need some guidance please

[aaron4915]

Hello everyone! I need some help as this is the first Mopar I have owned. Here is the lowdown. I have a 68 roadrunner 383 big block engine in my 76 dodge power wagon. I have had the truck for just about a year with no issues. Just recently when I was driving the motor acted fuel starved and died around 3000 rpm. it fired and drove fine for about a week. Now the problem happens every time I drive the truck and usually when I get around 3000 rpm. The truck will restart after about a minute and drive away fine until I get up the rpms. I have changed the fuel pump and fuel filter and that hasn't helped. I have a protronix point conversion on the motor. Do you guys believe it could be a carb issue or ignition? Am I missing something? Thank you for all your input!

 

[Aarons Air]

Sometimes Chrysler motors can be difficult to diagnose. This video explains a lot. Hope it helps.

 

[flypaper]

electrical will always be the weakest link
that is where I would start

 

[Lefty71]

This video explains a lot. Hope it helps.

I hate when I have to have my Dingell Arm Re-Segregated. That's a bitch to do without the proper 7" Gangley Wrench.

 

[greycharger]

change the fuel filter

edit: missed the changed filter part. Still sounds like fuel starvation

 

[Durandal25]

Sometimes Chrysler motors can be difficult to diagnose. This video explains a lot. Hope it helps.

Peed my kilt when I saw this......lol, still laughing. Awesome.

 

[dvw]

Leave the air filter off. When it dies be ready with carb spray, brakeleen, etc. Jump out, spray. Does it start or just crank? If it dies every time bring a helper. Yank the coil wire and test for spark. Just crank? I'd be looking at the Petronix unit. Granted these tests need to be done quick as you state it starts in the minute or so afterward. Narrow it to fuel or spark first.
Doug

 

[Aarons Air]

I hate when I have to have my Dingell Arm Re-Segregated. That's a bitch to do without the proper 7" Gangley Wrench.

Even with the 7" gangley wrench, i have to use a cheatwr bar ! Ugh.

 

[moparwacko]

Sometimes Chrysler motors can be difficult to diagnose. This video explains a lot. Hope it helps.

Sorry for no help, but when you get the side bumbling stopped it will be fine.

 

[turbine68rt]

I had a similar issue with my 440 before doing a rebuild and found after 112k miles the original fuel pump pushrod was worn on the cam end, limiting the pump stroke and starving it under load. Maybe check the length of yours compared to a new one to eliminate that as a suspect.

 

[road chicken]

Sounds like it's fuel starved. Sounds just like a clogged filter, however, since you changed that and the pump the only things left are a clogged feed line /intake tube. Second, possible needle seat issue in the carb. Not opening all the way and you're sucking the bowls dry faster than they can fill. The pump rod is something to check as Turbine68rt points out, ( I'll bet that was fun one to troubleshoot down to). If it fires up and runs to 3k without backfiring or being sassy the ignition probably isn't the culprit since the issues would show lower in the range as well. No guarantee, just probability.

 

[Don Frelier]

I would suggest the fuel pump pushrod, next the fuel screen on the sending unit.
Finally, I had an orange mopar box that acted a bit like you describe for a whole summer(maybe at 4,000).

 

[Lefty71]

It's possible the igntion coil is quitting on you, but I doubt it would happen in such a fashion, menaing ~3,000rpm. What type of fuel pump, mechanical??

Welcome to the group by the way. Sorry we were ribbing you a little, but post #2 was just too dang funny!

 

[Aarons Air]

It's possible the igntion coil is quitting on you, but I doubt it would happen in such a fashion, menaing ~3,000rpm. What type of fuel pump, mechanical??

Welcome to the group by the way. Sorry we were ribbing you a little, but post #2 was just too dang funny!

Yes, sorry for the ribbing.

 

[BB BELLA]

if it happens everytime I'd put a timing light on it and see what that says at 3000.
hit throttle and see if any fuel left in accel. pump!
could be broke wire on pickup coil that's shorting out!

 

[mopar 3 B]

Built in rev limiter. Some pay big bucks for that. Now to figure how to move it to 5500 instead of 3000.
But a bad coil would just make it go flat and loss power. Fuel can only be checked under load. Have you checked rubber fuel line yet. They could be going bad on the inside and restricting flow.

 

[aaron4915]

Thanks for all the responses guys. Some were helpful lol. I am running a electric fuel pump and no mechanical. I have not inspected the rubber fuel line but I will look at that next.

 

[YY1]

brain?

I've also had a bad wire in the distributor pickup coil harness cause the same problem.

The first one was an SOB to find.

 

[greycharger]

Run the engine in the dark and see if you find anything.
Bought a car once, the guy drove for the test drive and was real light on the throttle. Seemed to run okay. While I'm looking at it, some other guys came to check it out. It's sitting there idling and one of them blips the throttle. It misfired when it got some rpm's going and I saw the coil grounding through the boot. They were Chinese, so I don't know what they said to each other, but they left. I knew the guy's dirty secret and told him I could only afford this much. SOLD! he said. A primary wire fixed the issue and it would rev easily to 5500 without a miss.

 

[Ernie ingling]

Pull fuel tank pickup suspect sock getting clog from firt in tank.