What could it be
Thread Starter
|
Senior User
Joined: Jan 2013
Posts: 210
Likes: 0
From: New Mexico
What could it be
Well I've gone through two differant rebuilt carbs, my truck starts fine now compared to it wouldnt start at all before, it will idle fine for you to set timing, etc, tap the accelerater in neutral and it pops and dies, not quite a backfire just pops and thats it. Messed with the jets, idle and that stuff. New fuel pump, lines, clean tank, new distrubuter, plugs, points, wires everything gaped, good gas. Ive rebuilt probably 70 or 80 percent of this truck and just getting so frustrated i think im getting ready to tear it apart and sell whatever parts I can
Mountain Pass
Joined: Apr 2013
Posts: 138
Likes: 18
From: Moriarty, NM
Sounds like accelerator pump on carb is not working properly. with engine off look down carb and move throttle you should see two solid streams of gas in the throat of carb just below choke plate. If not a solid stream of fuel then the diaphram make be bad or the passages are clogged.
Hotshot
Joined: Mar 2013
Posts: 14,255
Likes: 199
From: Phoenix, Az.
I agree. Sounds like the idle curcuit has fuel but not the other curcuits. If this is a holley it sounds like the metering plate that the jets screw in to has some crap in it. The two plugs on the top of it would have to be removed to totaly clean it out. BTW, they were rebuilt by who?? A qualified shop with real carb soak?
Thread Starter
|
Senior User
Joined: Jan 2013
Posts: 210
Likes: 0
From: New Mexico
They were both motorcraft and they spray fuel into the throats if I look down. The carbs were rebuilt in town by a guy that rebuilds trucks like these.. he knows what hes doing but im starting to think its not the carb. I went out and tried to start it today and now it wont
Fleet Mechanic
Joined: May 2001
Posts: 1,396
Likes: 4
From: Cupertino
It idles well so it sounds like there are no vacuum leaks. You know what you are doing with the carb and of course the choke is set properly. The problem might be the distributor plate and vacuum advance.
Try this: Pull the vacuum advance line to the distributor and plug it at the carb. Dry the plugs, get it started and idling. Punch it. Normally this sharp drop in vacuum jerks the plate. Bad bushings or something screwy with the diaphram can misalign points and maybe cause your problem. If the problem goes away, replace the advance unit or better yet the distributor.
It is worth a try.
Don't quit yet. There is one simple thing that is causing your problem. You haven't found it yet but you will.
Semper Fi
Try this: Pull the vacuum advance line to the distributor and plug it at the carb. Dry the plugs, get it started and idling. Punch it. Normally this sharp drop in vacuum jerks the plate. Bad bushings or something screwy with the diaphram can misalign points and maybe cause your problem. If the problem goes away, replace the advance unit or better yet the distributor.
It is worth a try.
Don't quit yet. There is one simple thing that is causing your problem. You haven't found it yet but you will.
Semper Fi
Hotshot
Joined: Mar 2013
Posts: 14,255
Likes: 199
From: Phoenix, Az.
Well I've gone through two differant rebuilt carbs, my truck starts fine now compared to it wouldnt start at all before, it will idle fine for you to set timing, etc, tap the accelerater in neutral and it pops and dies, not quite a backfire just pops and thats it. Messed with the jets, idle and that stuff. New fuel pump, lines, clean tank, new distrubuter, plugs, points, wires everything gaped, good gas. Ive rebuilt probably 70 or 80 percent of this truck and just getting so frustrated i think im getting ready to tear it apart and sell whatever parts I can
Fleet Mechanic
Joined: May 2001
Posts: 1,396
Likes: 4
From: Cupertino
Jeffa may be right. Popping is lean but also bad ignition.
If you have gasoline peeing down the carb throat at it will not start, you have probably wetted the plugs with gasoline.
Do what I said: Pull the vacuum line at the distributor and plug it with a #10 machine screw. Dry the plugs with a torch, replace them, and it will fire.
If you have gasoline peeing down the carb throat at it will not start, you have probably wetted the plugs with gasoline.
Do what I said: Pull the vacuum line at the distributor and plug it with a #10 machine screw. Dry the plugs with a torch, replace them, and it will fire.
Trending Topics
Thread Starter
|
Senior User
Joined: Jan 2013
Posts: 210
Likes: 0
From: New Mexico
It idles well so it sounds like there are no vacuum leaks. You know what you are doing with the carb and of course the choke is set properly. The problem might be the distributor plate and vacuum advance.
Try this: Pull the vacuum advance line to the distributor and plug it at the carb. Dry the plugs, get it started and idling. Punch it. Normally this sharp drop in vacuum jerks the plate. Bad bushings or something screwy with the diaphram can misalign points and maybe cause your problem. If the problem goes away, replace the advance unit or better yet the distributor.
It is worth a try.
Don't quit yet. There is one simple thing that is causing your problem. You haven't found it yet but you will.
Semper Fi
Try this: Pull the vacuum advance line to the distributor and plug it at the carb. Dry the plugs, get it started and idling. Punch it. Normally this sharp drop in vacuum jerks the plate. Bad bushings or something screwy with the diaphram can misalign points and maybe cause your problem. If the problem goes away, replace the advance unit or better yet the distributor.
It is worth a try.
Don't quit yet. There is one simple thing that is causing your problem. You haven't found it yet but you will.
Semper Fi
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread Starter
|
Senior User
Joined: Jan 2013
Posts: 210
Likes: 0
From: New Mexico
The popping is from a lean mixture when you crack the throttle but no extra gas coming from the carb to compensate as usual. I think it is bad fuel pump. By chance is it a NAPA brand one you installed? In the last week or two I have seen 3 or 4 guys having trouble with replacement fuel pumps on this forum. All of them NAPA. Including my own Bump. Check you engine dipstick and see if any gas in the oil pan.
Thread
Thread Starter
Forum
Replies
Last Post
ghunt
General Automotive Discussion
4
Nov 18, 2007 12:42 AM
Shane269
Fuel Injection, Carburetion & Fuel System
3
Jul 3, 2005 05:36 PM