Truck shuts off?

[gungfudan]

Ok so the timing issue is fixed but for some reason the truck still bucks hard some times and then shuts off. Why is it doing this? it runs great except when it decides to do that.

 

[Mark_88]

The bucking sounds like a possible fuel issue...like water in the gas or your fuel pump is cutting out...did you replace the fuel pump with the new motor?

Another source of the engine shutting off sporadically is the wire clip under the hood on the drive side...the one with the lights, horn and others...there is a big power line (12 gauge wire) running beside it...check all those connections carefully...the main power that goes to the side post on the solenoid will kill the engine completely...plus all he other lights in some cases...but there is usually a boot on the solenoid connector...make sure that is tight and clean...

Only other thing I can think of is if you still have any of the connectors for the emission controls, one may be opening under vacuum but the open end is not connected and it is causing an excess of raw air to hit the carb...so it is a vacuum leak...and the air pump is something that may be involved as it works under vacuum to open the air pump that should push air into the cat under load.

 

[gungfudan]

First I want to thank you Mark for all of your responses. You are probably the first to reply all the time. So THANK YOU!!!!!! I did replace the fuel pump and the filter. We got rid of a lot of wiring that was for the old carb. I have a book that shows wiring diagrams for 1988 Bronco 2 and Rangers. I will check the connections and see. I also ran sea foam in my gas tank yesterday seems to be helping it still shut off on me twice this morning. But it is not bucking as much.

 

[gungfudan]

Ok I checked out the wires and everything is good and tight and in good condition. I drove it yesterday and it seemed to do fine do not shut off and ran great hoping it was just water in he has we will see today. I am going to drive it around a lot and then go fill it up with 100% petroleum

 

[Mark_88]

Thanks for saying Dan...

Sounds like you may have taken care of it with the seafoam...I guess I wasn't thinking clearly because I remembered after that you had swapped carbs and that would have eliminated most of the vacuum leaks...and as long as you didn't remove the carb from the intake it would have no bearing on that either.

I guess the term "bucking" might be a bit confusing because I've had engines buck and then ones that did a bunny hop...the bunny hop was almost always a wonky fuel supply thanks to the fuel pump cutting out sporadically...the bucking was usually a timing issue or bad/watered fuel.

I've also had issues with "run on" where the engine doesn't shut off when you turn the key and it sort of bounces around as it is trying to shut down. So, again, that doesn't apply to what you described initially.

Not familiar with seafoam because I've never actually used it, but if it is supposed to get rid of water then it may have accomplished what you needed. Filling up with good gas might be the best thing for now.

Hope it stays running well, but keep us posted otherwise...

 

[gungfudan]

So the engine still shuts off and the problem is when I replace the sending unit I stuck a piece of hose that was made for gas on he end to reach the bottom of the tank. But that hose is not made to be submersed in gas it is only made for gas to run through it. So I believe the hose has designated so when the tank sloshes around it shuts off or is on an incline it does he same thing. The submersible hose that is made for gas is $30 a foot!!!!!!!

So does anyone have any ideas of what I can do to make the sending unit tube to reach the bottom? I was thinking about braising a piece on the end of it. Oh by the way you have to buy it by the foot.

 

[zekew64]

Some clarification, Mark 88:

What you call a "run-on" engine is known as dieseling--in essence, the engine is so warm that the engine self-detonates, attempting to remain running.

 

[scheff]

my ranger did this to when is got to 1/4 tank of gas. i changed the fuel filter and i had black gas running out of it. after i changed that it dosent do it any more. hope this helps some.