I have recently had a problem with my truck, it stutters or cuts out like its not getting enough fuel. So the first thing i thought was a clogged fuel filter, I checked it out and it had some nasty looking stuff in it so i changed it out with a new one. Even though i changed it out it still is acting the same way.

When i was driving home from school coasting down the hill not on the gas i heard two loud pops, i am pretty sure it backfired out of the carb. So i shut it off and checked everything out and when i got in to start it it wouldn't fire. I let it sit for a few minutes and it started up, and drove it home slowly and it was running fine at slower speeds.

It does it the worst at a higher rpm and its pretty bad when driving, my guess is its maybe electrical.

Please post if you have any ideas what might be causing my problem, i would appreciate it.

 

Here is the video


It does it when it gets to the higher rpm and it did it a little after i let off the second time.

 

could be a weak fuel pump

 

Its a fairly new fuel pump, and it ran fine until a couple days ago. The pump is rated for 4-6psi i believe, could something happen to it to make the output of the pump less?

 

is the fuel pump electric or manual? i had an electric one die within 2 weeks. it could also be a vacuum leak

 

electric
If it was a vacuum leak wouldn't that cause it to run bad all of the time?

 

pump output will remain constant.

have you checked the mix, air/fuel ratio?? looks like you got allot of smoke coming out. could be running rich and when you go into the higher rpm band its flooding the engine and it cannot burn up all the fuel... maybe.. also check you plugs, wires, grounds (yup)... air filter.....

vacuum leak could be intermitent...

 

How would i check the air/fuel ratio? The wires should be good they are a couple months old, so are the plugs but i will pull some and see what they look like. And i will see about the grounds. Oh and when i started it a little bit ago it died on me again and would crank but wouldn't turn over.

 

definitely either a air/fuel mixture **** up or a timing issue whether it be with the coil/distributor or ecm.

if it cranks but wont fire then you have a spark issue or fuel delivery issue. gimme a sec to find a answer if i can.

 

Ford Ranger/Bronco II TFI Ignition Diagnostics

this should help. pretty sure you have the same/similar system. got to love their tech library....

just noticed you have a 302.....

 

Well i got it started and it wasn't smoking like the video at idle but with someone watching i was revving it up and they said it started smoking more and after i let off and let it idle for about 30 sec it died again.

 

whats the exhaust smell like???

 

running way rich. pull your plugs and look at them

 

It smelled fairly rich

Would that cause my truck to die? It seems like its running rich and then floods itself, because i can't start it right after, but it will if i wait a little bit.

 

ding ding ding..... sounds like we have a winner.

time to go study, have a cummins m-11 write up to do and mid-terms next week, good luck!!

 

So adjust the carb and probably new plugs?

 

Well i pulled a couple plugs and they looked perfectly normal.

 

Does it crank over hard? What happened to the engine in a previous life (backyard performance?) Possible that it's way out of time on ignition.

 

No it cranks over good, i don't really know the history on the motor because i bought the truck with it in it. I was told it was rebuilt and has about 25k on it, timing is one of the things i thought of because of the backfires the one day i was driving it. But last time it was in the shop they checked the timing and it was where it was supposed to be.

 

a word of advise ,, when ever you replace an electric fuel pump that rests inside a fuel tank

always,always check inside the fuel tank for rust / grit / sludge or any other contaminants

sounds the fuel pump small fine pickup screen filter is nearly plugged up

 

I say check the carb

just my 2 cents

 

What carb you running if its a holly an it smells as if its running rich an don't run to well at higher RPM's most likely the power valve in the carb needs replaced one good back fire will ruin a power valve if this is the case replace it or they also make a power valve elimination kit ... hope that can be of some help