Hesitation on acceleration

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

europtics

New member
Joined
Aug 7, 2007
Messages
3
Reaction score
0
I have an 85 Bronco II, 2.8, auto, and have had this problem for some time. When I accelerate from a stopped position, it almost stalls and have to jiggle the peddle to get it to go. Also, when I slow for a turn and try to accelerate out of it, it almost stalls. I just had the carburetor rebuilt and the fuel pump replaced. What now?

 

madmax

Member
Joined
Apr 5, 2007
Messages
211
Reaction score
7
Location
quakertown pa
did it do that before the carb rebuild? are you flooring it to take off or hitting the gas lightley, you might be drowning the engine.

 
OP
OP
E

europtics

New member
Joined
Aug 7, 2007
Messages
3
Reaction score
0
did it do that before the carb rebuild? are you flooring it to take off or hitting the gas lightley, you might be drowning the engine.

Yes, I've had this problem for some time and thought it was the carberator. Had it rebuilt by a good source and still have the problem. Just depressing the pedal slightly as normal take-off and it wants to stall. Have to jiggle the peddle a little and it will "wake-up" and go. On turns, it will want to do the same thing accelerrating out of it. Please reply soon as I need to find out the truth about if its the carb guys or?

Thank you,

Doug

 
OP
OP
E

europtics

New member
Joined
Aug 7, 2007
Messages
3
Reaction score
0
did it do that before the carb rebuild? are you flooring it to take off or hitting the gas lightley, you might be drowning the engine.

Yes, I've had this problem for some time and thought it was the carberator. Had it rebuilt by a good source and still have the problem. Just depressing the pedal slightly as normal take-off and it wants to stall. Have to jiggle the peddle a little and it will "wake-up" and go. On turns, it will want to do the same thing accelerrating out of it. Please reply soon as I need to find out the truth about if its the carb guys or?

Thank you,

Doug

 

madmax

Member
Joined
Apr 5, 2007
Messages
211
Reaction score
7
Location
quakertown pa
Ill assume youve cleaned your air filter, the carburator could have been rebuilt just fine but need adjustment.

You could be having ignition issues (Have you checked the plugs, cap and rotor?)

You could have a fuel pump that is on its way out taking a moment to respond - You'll need to check the fuel pressure as the engine stumbles.

I can't remember if those engines have EGR valves but that could be opening up when you first hit the gas causing it to drown the engine in exhaust.

You could also have wet gasoline, gasoline does absorb some water, and as it ages it loses the light fractions (mostly the octane), if you've not got a full tank try draining it and filling it with high test.

Also check the crank case breather where it runs into the carb, it could be fouling stuff up happened on my father's 78 F150 with a 302, he just ran the damn breather down, to **** with using the engine to burn off the tiny bit of oil fumes coming from the crankcase.

 
Last edited by a moderator:

vak74

New member
Joined
Sep 18, 2007
Messages
1
Reaction score
0
If the problem is the same whether the engine's cold or hot, I think it's way more likely to be in the accelerator pump adjustment. In the couple of seconds accelerating away from a stop, the carb feeds out of the gas in the float bowl, so the fuel pump isn't an issue. If it's breathing badly (dirty air cleaner etc.) it's just gonna run crappy all the time, not just on acceleration. It could also be vacuum advance, but that would generally show up if you were having problems when flooring it, or as a stumble in acceleration after the RPMs come up and the tranny shifts, not so much in mild acceleration from a stop where engine vacuum doesn't come into play much. If you don't fiddle the gas pedal and push it just a bit further down does the engine spit out the tailpipe? If so, it's almost surely not enough fuel on acceleration.

If it's a stock Ford carb, there's two key adjustments that vary carb-by-carb: the accelerator pump lever adjustment, and the accelerator pump stroke adjustment. The lever adjustment is done with the throttle held wide open (engine off) and measuring the gap between the lever and the adjusting *****. Don't know the exact gap for the Ford carb (for a Holley it's .015). The stroke adjustment is all about making sure that the cam that pushes on the accelerator pump is indexed to the same hole as it was before the rebuild ... or you're in for simple trial and error with different settings until the car runs right.

 
Last edited by a moderator:

White90Bronco

New member
Joined
May 2, 2005
Messages
89
Reaction score
1
I have an 87 Ranger that's doing the same thing listed here...hesitating on takeoff...mine has 2.9 w/ fuel injection...it has new cap, plugs, rotor, air & fuel filter, the truck only has 53,000 original miles on it...my dad has been a mechanic all his life and he's leaning towards the egr valve...any other suggestions?

Thanks,

Casey

 

BroncoJoe19

Active member
Joined
Dec 26, 2007
Messages
2,092
Reaction score
12
Location
New Jersey
Sorry, but I know nothing about the particulars of a 85 BII. You may want to put some info in your sig file, obtainable through the "my controls" section.

Have you checked for vacuum leaks?

Do you have a vacuum advance?

IF so, is it working properly?

IF you do not have a vacuum advance, is your SPOUT conector connected?

Are the connections clean?

I'm guessing that I won't get a response to this question... I just noted that the thread is nearly a year old!

 
Last edited by a moderator:

Members online

No members online now.

Latest posts

Forum statistics

Threads
22,509
Messages
135,880
Members
25,108
Latest member
Utahstroke
Top