• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

How to adjust Idle on 2.8 v6?

Forlorn

New Member
Joined
Oct 7, 2022
Messages
12
Reaction score
2
Points
3
Location
47362
Vehicle Year
1985
Make / Model
Ford Bronco II
Transmission
Manual
I got an 85 bronco ii that I am fixing up as a project car, got the car running now it's adjusting the high idle, it probably idles around 2k at the moment when it should be 800-900 is what the hood label says.
being new to carbed engines this looks like a lot to me, anyways I was on step num #74 where is the tach test terminal? if I even have one, and not go by ear.
IMAG0920.jpg
IMAG0921.jpg
 


Forlorn

New Member
Joined
Oct 7, 2022
Messages
12
Reaction score
2
Points
3
Location
47362
Vehicle Year
1985
Make / Model
Ford Bronco II
Transmission
Manual
clicked on 2.9 when I meant .8 still would appreciate any help.
 

snoranger

Forum Stuff Member
Forum Moderator
Supporting Member
ASE Certified Tech
TRS Event Participant
GMRS Radio License
Joined
Nov 25, 2007
Messages
12,091
Reaction score
11,640
Points
113
Location
Jackson, NJ
Vehicle Year
'79,'94,'02,'20
Make / Model
All Fords
Transmission
Manual
2WD / 4WD
2WD
My credo
I didn't ask for your life story, just answer the question!
I moved it to the correct forum for you.
 

AndyB.

Active Member
Joined
May 26, 2014
Messages
430
Reaction score
124
Points
43
Location
Cincinnati, OH
Transmission
Automatic
Green and yellow wire on the coil, I use an alligator clip to connect to the terminal, then clip the tach to the alligator clip.
 

Forlorn

New Member
Joined
Oct 7, 2022
Messages
12
Reaction score
2
Points
3
Location
47362
Vehicle Year
1985
Make / Model
Ford Bronco II
Transmission
Manual
Green and yellow wire on the coil, I use an alligator clip to connect to the terminal, then clip the tach to the alligator clip.
IS the Dk GRN/YEl the negative wire going to the coil then?
85_B2_28.jpg
 

Angie

Well-Known Member
V8 Engine Swap
Joined
May 18, 2008
Messages
1,476
Reaction score
338
Points
83
Location
Vancouver area BC Canada
Vehicle Year
92 & 83 project
Make / Model
Ford
Engine Type
V8
Engine Size
4.0L 302
Transmission
Automatic
One thing to check and be positive about is that you don't have any vacuum leaks, they will send you idle settings out of whack even before you touch the carb.
 

Forlorn

New Member
Joined
Oct 7, 2022
Messages
12
Reaction score
2
Points
3
Location
47362
Vehicle Year
1985
Make / Model
Ford Bronco II
Transmission
Manual
One thing to check and be positive about is that you don't have any vacuum leaks, they will send you idle settings out of whack even before you touch the carb.
I may have some, but I've been pretty thorough in making sure they're capped if not connected.
another thing I noticed is it revs at 2.5k and if I rev the engine through the carb, like push the accelerator or whatever it called on it, it goes back down to idle at 900ish, maybe something is stuck from it sitting, probably just really need to clean the carb
 

AndyB.

Active Member
Joined
May 26, 2014
Messages
430
Reaction score
124
Points
43
Location
Cincinnati, OH
Transmission
Automatic
I may have some, but I've been pretty thorough in making sure they're capped if not connected.
another thing I noticed is it revs at 2.5k and if I rev the engine through the carb, like push the accelerator or whatever it called on it, it goes back down to idle at 900ish, maybe something is stuck from it sitting, probably just really need to clean the carb
Probably not.

It sounds like you’re in over your head. There could be a number of causes for the high idle, you’re just going to get a bunch of guesses here. You’ll wind up replacing your coolant temperature sensor, throttle position sensor, idle speed control motor. Then you’ll decide you need a rebuilt carburetor. Someone will tell you to remove the EGR valve and the smog pump for more horsepower. Eventually you’ll give up, install a Chinese carburetor, rig up an ignition system from a GM vehicle, the complain you get 13 miles to the gallon.

Try to find someone capable of working on these that will go through the diagnostic steps to find and repair the root cause rather than guessing.
 

fastpakr

Forum Staff Member
Forum Moderator
Supporting Member
Article Contributor
U.S. Military - Veteran
V8 Engine Swap
TRS 20th Anniversary
TRS Event Participant
Joined
Aug 6, 2007
Messages
7,553
Reaction score
2,354
Points
113
Location
Roanoke, VA
Vehicle Year
1999
Make / Model
Ford
Engine Type
V8
Engine Size
5.0
Transmission
Automatic
2WD / 4WD
4WD
Tire Size
285/75-16
Probably not.

It sounds like you’re in over your head. There could be a number of causes for the high idle, you’re just going to get a bunch of guesses here. You’ll wind up replacing your coolant temperature sensor, throttle position sensor, idle speed control motor. Then you’ll decide you need a rebuilt carburetor. Someone will tell you to remove the EGR valve and the smog pump for more horsepower. Eventually you’ll give up, install a Chinese carburetor, rig up an ignition system from a GM vehicle, the complain you get 13 miles to the gallon.

Try to find someone capable of working on these that will go through the diagnostic steps to find and repair the root cause rather than guessing.
That's a remarkably cynical take when no one has suggested shotgunning parts at the problem to date.
 

Angie

Well-Known Member
V8 Engine Swap
Joined
May 18, 2008
Messages
1,476
Reaction score
338
Points
83
Location
Vancouver area BC Canada
Vehicle Year
92 & 83 project
Make / Model
Ford
Engine Type
V8
Engine Size
4.0L 302
Transmission
Automatic
Ok, I really don't want to get too involved in this thread, however, there are a couple things i would look into. on the couple 2.8's engines i have come into contact with in these trucks, they are at the start of the "electric, and sensor" era ... with all the small hoses and gizmos on the fender skirt. are all these connected properly? and can you take a couple pics of them all. as from what i can gather they are what control the engine, and control the settings. myself I don't have a running truck with these things still attached, but i am thinking we need to know if yours are still there.

Second, can all your troubles be that the high idle screw is not working properly and is just sticking? something sounds like it is a mechanical problem and not a carb problem where you need to tear into "rebuilding" and going into the troubles you are seeming to want to take.

carbs are really not that complicated once you understand the basic functions of them.

give you an example, i recently bought a 84 truck with 2.8 that had a crazy idle problem.... after checking all the vacuum lines and such i was able to decipher that the brake booster was blown. Hence the vacuum leak and off, missing idle.

cheers and post up what it is you are looking at.

post #5 has a picture of what i am talking about. not saying yours is shot, however, this is something that is over looked on older trucks. they do rot and these are close to 40 year old rigs.


 
Last edited:

4x4prepper

Active Member
Joined
Feb 2, 2015
Messages
479
Reaction score
195
Points
43
Location
Atlanta
Vehicle Year
1985
Make / Model
Ford
Transmission
Manual
How about a picture of the engine from the passenger side and a picture from the front of the carb with the air cleaner removed? No sense in trouble shooting a system step by step if it is not stock going "by the book".

If it was me, I would let it warm up and once I was sure the thermostat was open, I would test it for base timing (no advance), vacuum at idle with base timing, and see where teh RPM range is then.
 

Angie

Well-Known Member
V8 Engine Swap
Joined
May 18, 2008
Messages
1,476
Reaction score
338
Points
83
Location
Vancouver area BC Canada
Vehicle Year
92 & 83 project
Make / Model
Ford
Engine Type
V8
Engine Size
4.0L 302
Transmission
Automatic
Any follow ups on this problem?
 

Sponsored Ad


Sponsored Ad

Top