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My Bronco Acceleration

SSDDBRONCO

Bronco Guru
Joined
Nov 12, 2009
Messages
2,170
Loc.
Los Angeles
Hey whats up. I was wondering why my bronco takes off pretty slow when i step on the gas. It is a stock 302 but has an exhaust, headers, new holly ta carb, c4 auto, 33 tires, 4.10 gears, and thats about it. Just wondering why it would accelerate slowly. What should i tune up or buy to make it accelerate faster. I know its not a Mustang Cobra ;D but i have seen other broncos that are stock (like mods i have) and take off way more faster than mine does. Help and ideas would be great.
Thanks:cool:
 

DonsBolt

Bronco Guru
Joined
May 5, 2005
Messages
5,249
Loc.
Chestnut Hill, Mass
which TA the 470 or the 670? If it is the 670 might be too rich, does it smell like gas?

Also whats your timing set at, depending where it is set you could bump up the timing a little and get some more power out of it
 
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SSDDBRONCO

SSDDBRONCO

Bronco Guru
Joined
Nov 12, 2009
Messages
2,170
Loc.
Los Angeles
i have the ta 470, and i never did anything to the timing since i bought it almost a year ago. Should i get it timed?
 

BronCowie

Contributor
Old Timer
Joined
Apr 24, 2007
Messages
8,024
Loc.
Vancouver, WA
Is your C4 down shifting to 1st when you stop? If not, starting from 2nd or even 3rd gear will feel like your driving through mud trying to get up to speed.

Try shifting to the "1st" position instead of "D" and see if there is a difference from a full stop. If that is what's going on, let us know and you'll get a bunch of C4 trouble shooting advice.
 

crab

Bronco Guru
Joined
Feb 23, 2004
Messages
2,264
What kind of RPM's are you building between shift points? Could be Tranny/TC issues??
 
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SSDDBRONCO

SSDDBRONCO

Bronco Guru
Joined
Nov 12, 2009
Messages
2,170
Loc.
Los Angeles
Is your C4 down shifting to 1st when you stop? If not, starting from 2nd or even 3rd gear will feel like your driving through mud trying to get up to speed.

Try shifting to the "1st" position instead of "D" and see if there is a difference from a full stop. If that is what's going on, let us know and you'll get a bunch of C4 trouble shooting advice.

well i recently put a lokar kick down cable thinking that it would help but is still the same and i do believe it does down shift to 1st.
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
Timing may help slightly but it sounds more like a tranny slippage issue. Could be wear in need of adjustment ect. Might be a good idea to change the fluid and filter.
 

crab

Bronco Guru
Joined
Feb 23, 2004
Messages
2,264
Did you install the Lokar kickdown because then tranny wasn't kicking down? To early to tell if you have tranny issues but sounds like it me. Should jump out of the hole if everything is working corectly.
 
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SSDDBRONCO

SSDDBRONCO

Bronco Guru
Joined
Nov 12, 2009
Messages
2,170
Loc.
Los Angeles
Did you install the Lokar kickdown because then tranny wasn't kicking down?

Well i installed it because the previous owner took off the kickdown and was manually shifting through the gears, which i have the B&M Quicksilver shifter
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
You never know what a PO did or didnt do. But you might try adjusting the bands, and kickdown and shift linkage. Might also want to replace the seals on the servo as it could be leaking and causing the issue as well. Might want to check to see what servo it has as well. There should be a letter cast into the cover H or R is good anthing else kinda debateable but I'm pretty sure that broncos came with the H servo.
But in the end its probably about time for a rebuild.
 

1970mule

Bronco Guru
Joined
Dec 20, 2007
Messages
1,515
almost sure its the TA, they are a pain if not impossible to properly tune. i never was able to get the dead spot out of mine so i went to EFI. will see how that works once i am done.
 

Explorer

Bronco Guru
Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
I'd still check some simple stuff before sending to the tranny shop. Make sure you're getting full throttle travel and yes, set the timing.
 

rsharpnm

Sr. Member
Joined
May 2, 2005
Messages
712
Loc.
Las Cruces
What he said

x3. Get a vacuum gauge and a 1/2" wrench. Loosen the distributor clamp and turn it until you get the maximum vacuum reading on the gauge. Tighten the clamp and see what that does. Listen for *ping* or engine rattle on acceleration. If you hear it, jump out, loosen the bolt, and turn the distributor very slightly back. Repeat as necessary (ping = bad; too much advance on timing)

You are now timed correctly. If the problem persists, check carb/mixture. I'm not a big fan of Holley, but I'm sure they can be tuned like any other carb. Again, vacuum gauge and now a screwdriver to adjust mixture. Go for maximum vacuum.

Now you're tuned. If the problem persists, look into transmission issues, but riddle me this: can you manually put it in first gear? If you've done all the above and your are SURE you're in first gear, then your problems may be bigger.

Go nuts!
 

BroncoDawg

Sr. Member
Joined
Mar 4, 2005
Messages
672
Loc.
Bishop, CA
"I do believe it does down shift to 1st" Make darn sure first by manually shifting down at a stop and see if you're in first. Will be a huge difference.
 
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SSDDBRONCO

SSDDBRONCO

Bronco Guru
Joined
Nov 12, 2009
Messages
2,170
Loc.
Los Angeles
thanks everyone for the help i will get my timing done and see if it continues. i will let you guys know if it is anything bad. GOD i hope not!
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
I'm going to kinda disagreee on setting timing to maximum vacuum as that doesnt always work on all engines. You want a high steady vacuum reading not nessearily the highest reading. Still a better method is just to use a timing light set the timing to around 10 degrees. You might be able to up it a few degrees from 10 as well. I can usually run about 12 degrees with no issues.
In either case you'll probably have to readjust the idle mixture screws this is where you will want to obtain the highest steady vacuum you can then verify it doesnt ping on hills.
 

bad 68

Sr. Member
Joined
Jul 1, 2010
Messages
921
Loc.
Northest Washington
Do you have a tack? First gear with those tires and 4.10 gears should be screaming at 30 mph. Ford automatics stay in second gear from a dead stop if the shifter is in second. You say you have a B&M shifter. Maybe out of adjustment. This would make it a turd.
 
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