My new engine is dying on me

[mrtleavitt]

My brother and I just finished his truck a few months ago. It's a pretty sweet 390. Edelbrock aluminum heads, MSD ignition, headman headders, pretty tall cam, plus lots of other things. Well, as we drive it down the road it dies. There's not much reason or rhyme to the problem. One time it died as we were turning about 4,000 RPM and another at a stop sign just idling. It takes 5-20 minutes for it to start back up. Everything on it is new. It has a edelbrock fuel pump with a Edelbrock 750 manual choke. It doesn't run long enough to get vapor lock, it's usually within the first 5 minutes of driving. Fuel filters are good, fuel lines are clean as well as the gas tank. Any ideas guys?

[Ranchero50]

Is it fuel dieing of ignition cutting out?

[mrtleavitt]

Fuel

[SteveC]

check your gas cap. if not check your fuel tank vaper lines (if applicable).

also next time it dies try getting out of the truck and loosen the gas cap and see if air sucks in.

[willowbilly3]

Fuel

Please tell us how you determined it was fuel? Does it still have a strong spark?

[mrtleavitt]

Ya, it still has spark at the plugs when it won't start. When it does die, it begins to stutter and then run on just a few cylinders instead of the 8. The jetting is stock on the 750 edelbrock so I couldn't imagine that it is too rich or too lean to make these problems. It might be a little rich or lean, but not enough to cause the truck to die.

[willowbilly3]

Any chance it has water in the tank?

[fordman]

checking the gas cap and checking to see if anything has gotten into the tank are both great ideas. someone could have just put something in the tank.

[averagef250]

I had a similiar problem with an edelbrock 750 carb I bought used. The edelcraps have a fuel line cast into the top cover with a fuel filter inside. The carb I got must have been run on a vehicle with a really bad rusty fuel tank and the tiny rust particles got past the fuel filter and clogged up that fuel line. It was funny the way it happened too because the particles would all go to the side farthest from the fuel inlet so the cylinders on that side would starve for fuel.

If you have a new carb I doubt that's your problem, but it might be if it's a used one.

[mrtleavitt]

Thanks for the info, that's a crazy story averagef250. It is a new carb but it's worth checking the internal filter on the carb. I didn't know the carbs had one in there. That makes sense because my engine starts cutting out a few cylinders at a time so maybe it's doing the same. I have some free time today so I'll see what I can figure out.