Stumble on acceleration
Thread Starter
|
Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
Stumble on acceleration
Hey guys
So my Civic is down for the count and my powerstroke is getting a heart transplant.... That means Big Green is my daily commuter!!
Problems I ran into today:
Died on me while cruising at 55 mph, felt like fuel starvation, changed the fuel filter, started right up!
Now, when I accelerate very smoothly and gradually, no problem. Idles like a top. If I accelerate a little harder, it hiccups, bucks, and wants to die. What could be going on?
I have no history on the fuel pump, spark plugs, distributor (cap and rotor look good), or anything else really. It just started doing this after it sat for about 3 months. Common sense would be to measure fuel pressure, which I will do when I get a gauge and the plumbing to hook it in.
Thanks guys for any help... I am confident working on the powerstroke but haven't had much experience with gas motors.
So my Civic is down for the count and my powerstroke is getting a heart transplant.... That means Big Green is my daily commuter!!
Problems I ran into today:
Died on me while cruising at 55 mph, felt like fuel starvation, changed the fuel filter, started right up!
Now, when I accelerate very smoothly and gradually, no problem. Idles like a top. If I accelerate a little harder, it hiccups, bucks, and wants to die. What could be going on?
I have no history on the fuel pump, spark plugs, distributor (cap and rotor look good), or anything else really. It just started doing this after it sat for about 3 months. Common sense would be to measure fuel pressure, which I will do when I get a gauge and the plumbing to hook it in.
Thanks guys for any help... I am confident working on the powerstroke but haven't had much experience with gas motors.
Elder User
Joined: Oct 2016
Posts: 712
Likes: 1
From: Mesa, AZ
I've got a thread going titled "stumble" that's up to 3 pages of stuff you can check....last post was a week or so ago.
I haven't gotten to the bottom of mine yet, but things I've checked so far:
Things I haven't yet done is:
Replace fuel filter (next on the list)
Carb rebuild or at least a partial rebuild (have a kit)
Possible fuel pump? Mine looks newish though (not that that means anything)
I still have the stumble on mine as well, including the occasional backfire through the carb if I really step on it in 3rd or 4th gear.
I'll be following your thread. Your symptoms sound exactly like what I'm experiencing with my truck. I just have very limited time to work on it on weekends, so my progress is slow.
I haven't gotten to the bottom of mine yet, but things I've checked so far:
- Adjusted carb mixture to achieve maximum vacuum at idle
- Chased down and fixed any and all vacuum leaks (cracked hoses, bad seals, etc)
- Checked base timing
- Adjusted arm on accelerator pump
- Checked vacuum advance on distributor to ensure it's working
Things I haven't yet done is:
Replace fuel filter (next on the list)
Carb rebuild or at least a partial rebuild (have a kit)
Possible fuel pump? Mine looks newish though (not that that means anything)
I still have the stumble on mine as well, including the occasional backfire through the carb if I really step on it in 3rd or 4th gear.
I'll be following your thread. Your symptoms sound exactly like what I'm experiencing with my truck. I just have very limited time to work on it on weekends, so my progress is slow.
Senior User
Joined: Dec 2014
Posts: 279
Likes: 0
From: spokane
If it was a holley I would be of more use, but I've never run an edelbrock before, so in general, make sure all vac lines are good. If you have an auto I believe there is a vacuum solenoid that goes to the trans that is known for going bad. Check the base timing. Make sure all your plugs are in good shape as well as wires cap and rotor.
Just eliminate all the basics before tearing into anything basically.
Edit: noticed you said it sat for a little while, so it just might be time to rebuild the carb, but before doing that, you should definitely make sure the timing is correct and try to get the carb dialed in with a vacuum gauge.
Just eliminate all the basics before tearing into anything basically.
Edit: noticed you said it sat for a little while, so it just might be time to rebuild the carb, but before doing that, you should definitely make sure the timing is correct and try to get the carb dialed in with a vacuum gauge.
Thread Starter
|
Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
I started looking at some of the vac lines and they're starting to dry rot. I bet that's the problem, or at least one of the problems. I'll start there and work my way down the list. Thanks for the responses!
More Turbo
Joined: Apr 2007
Posts: 656
Likes: 5
From: Salisbury, PA
Your throttle return "spring" scares the crap out of me to the point I would not drive that thing even one block. I would not trust that thing to return the throttle and you may find yourself stuck at wide open throttle at a moments notice and the only way to stop that is to immediately shut the ignition off or somehow pull the gas pedal off the floor. There are many ways a more proper setup with an actual real spring can be installed.
Like krazyness I am only familiar with Holleys, but if you never had these issues with the truck before then I would suspect something like a vacuum hose is cracked or something minor in that regards. Not sure if Edelbrocks have accelerator pumps to assist the engine from getting from partial throttle to hard throttle without a stumble. The rubber diaphragms in these can crack on Holleys.
Some carb cleaner fuel treatment dumped in the gas tank can help fairly quickly to clean out any gunk in the carb that has built up over the years, but that from my experience has typically caused idling problems.
Like krazyness I am only familiar with Holleys, but if you never had these issues with the truck before then I would suspect something like a vacuum hose is cracked or something minor in that regards. Not sure if Edelbrocks have accelerator pumps to assist the engine from getting from partial throttle to hard throttle without a stumble. The rubber diaphragms in these can crack on Holleys.
Some carb cleaner fuel treatment dumped in the gas tank can help fairly quickly to clean out any gunk in the carb that has built up over the years, but that from my experience has typically caused idling problems.
Trending Topics
Thread Starter
|
Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
Yeah, I thought the spring looked sketchy but that's how the po had it, and I haven't had any problems. I'll get a new one tomorrow on my way to work.
I'll also pick up some vacuum lines and carb cleaner to check for vacuum leaks.
I'll also pick up some vacuum lines and carb cleaner to check for vacuum leaks.
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
Senior User
Joined: Dec 2014
Posts: 279
Likes: 0
From: spokane
Good catch on that return spring, that is scary... I think you're heading in the right direction with replacing old vacuum lines. Sometimes they look fine at a glance, but in actuality have a bunch of little cracks from getting brittle that you won't see until you start trying to remove them or play around with them.
Laughing Gas
Joined: Mar 2015
Posts: 885
Likes: 2
From: Pittsburgh
Power valve in the carb possibly? That would likely require a rebuild. Start with the easier stuff listed first though. Replacing rotting vac hoses will make the whole thing run better, made a huge difference for me.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
All carbs are dependent on good fuel delivery, proper pressure and volume, and then float height. Dying at highway cruise, is certainly possible a filter could do that but I'm wondering if maybe the fuel pump is wonky. In any case that's the first step, make sure pressure and volume is within spec.
Senior User
Joined: Dec 2014
Posts: 279
Likes: 0
From: spokane
Carbs can seem overwhelming, but if you take your time and keep everything organized on a nice big table or something it makes it a lot easier. Just go slow, watch plenty of videos on you tube and find a good step by step guide and you'll get it rebuilt in no time.