1986 Ranger runs rough cold


Alaska Diesel

Member
Joined
Sep 22, 2019
Messages
52
Reaction score
8
Points
8
Location
Palmer Ak
Vehicle Year
1986, 1987
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
I tried it in a different browser than Google Chrome and it worked.
I used Microsoft Edge
 


Rock Auto 5% Discount Code: 32B05A80BF19AF Expires: July 1st, 2020

Locotomb

Active member
Joined
Jul 26, 2017
Messages
114
Reaction score
51
Points
28
Location
Puyallup, WA
Vehicle Year
1988, 1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Engine Size
351w
Transmission
Automatic
2WD / 4WD
2WD
Total Lift
6inch custom fab lift/86
Total Drop
3 inch drop beams/88
Tire Size
35/12.5/r18
My credo
Fords and Drums
When the engine is cold the IAC should be open. When you start it up cold, pull the connector off the IAC. It's basically a solenoid that engages when cold, and allows fresh air to by-pass the throttle body (which would be closed). If you don't hear the solenoid disengaging and engaging when you disconnect/connect the connector (engine cold) there's an issue with it. Check the pdf file I attached earlier and see if you got a later model IAC. If so, according to the pdf, swapping the two wires should fix it.

You could also connect 12 volts to the IAC to test the solenoid. If it doesn't work, switch the wires and try again. If it doesn't engage with the polarity either way, it's bad. With 80 miles on it, it can't be clogged up.
Good info, it's surprising how often ford decides to change something that isn't broken. After this procedure and all others are exhausted, check your ECM. Mine was good except for the cold start scenario. Which made it seem like a bad IAC. You can loose data over time in different parts of the ecm.
 

Alaska Diesel

Member
Joined
Sep 22, 2019
Messages
52
Reaction score
8
Points
8
Location
Palmer Ak
Vehicle Year
1986, 1987
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
I have another ECM that is good I've put that on it and it's still the same.
 

Locotomb

Active member
Joined
Jul 26, 2017
Messages
114
Reaction score
51
Points
28
Location
Puyallup, WA
Vehicle Year
1988, 1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Engine Size
351w
Transmission
Automatic
2WD / 4WD
2WD
Total Lift
6inch custom fab lift/86
Total Drop
3 inch drop beams/88
Tire Size
35/12.5/r18
My credo
Fords and Drums
Sorry, you already mentioned that. From what I understand, the Engine while cold takes readings from the ECT, Airtemp, Map and the TFI at start to set the Cold Crank Scenario (Closed loop, computer controls timing and uses preset fuel ratios.). Then after it warms, it starts to read the O2 sensor and switches to an Open loop (Sets timing and ratios by the sensors) to control the idle/Fuel Ratio. Which is a warm cruise scenario (Cant remember the name actually). In conclusion, if its running like crap while its cold, first start of the day, then you either have vacuum issues, or could even be a lack of coolant in the system, so your ect doesn't get a correct reading. That's what I love about these trucks. It could be anything. One piece out of place and it runs like crap but alls good and it's a great little motor. I hope that helps.
 
Last edited:

Alaska Diesel

Member
Joined
Sep 22, 2019
Messages
52
Reaction score
8
Points
8
Location
Palmer Ak
Vehicle Year
1986, 1987
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
How would I test the TFI?
The TFI is on the distributor right?
 

Locotomb

Active member
Joined
Jul 26, 2017
Messages
114
Reaction score
51
Points
28
Location
Puyallup, WA
Vehicle Year
1988, 1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Engine Size
351w
Transmission
Automatic
2WD / 4WD
2WD
Total Lift
6inch custom fab lift/86
Total Drop
3 inch drop beams/88
Tire Size
35/12.5/r18
My credo
Fords and Drums
Yeah, Its horizontally located on the firewall side of distrib. Mine was going out for awhile and had the same symptoms then one day it just quit. I was going 45 and the truck just shut off. I thought it was the fuel pump at first and after I changed that out, and to no avail, figured out it was the module. Can't remember how but yeah. I run a 180 or 185 thermostat now to keep the engine bay cooler and haven't had an issue since. As far as testing it goes, Get a chiltons manual and follow their tests. Theres a certain window of numbers per wire that you should be within (ohm resistance test I believe) for it to pass. You'll have to take the module off to get to the connectors that are hiding. If I remember right, I had to thin out a 7 mm socket to get it off.
 

Alaska Diesel

Member
Joined
Sep 22, 2019
Messages
52
Reaction score
8
Points
8
Location
Palmer Ak
Vehicle Year
1986, 1987
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD

Alaska Diesel

Member
Joined
Sep 22, 2019
Messages
52
Reaction score
8
Points
8
Location
Palmer Ak
Vehicle Year
1986, 1987
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
I have an extra TFI module. What kind of grease is supposed to be used on it?
 

Alaska Diesel

Member
Joined
Sep 22, 2019
Messages
52
Reaction score
8
Points
8
Location
Palmer Ak
Vehicle Year
1986, 1987
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Ok thanks, I knew it was something different the dielectric grease.
 

Alaska Diesel

Member
Joined
Sep 22, 2019
Messages
52
Reaction score
8
Points
8
Location
Palmer Ak
Vehicle Year
1986, 1987
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Is there something else I can use?
Napa doesn't have heat sink.
 

Nez'sRanger

Active member
Joined
Oct 6, 2018
Messages
187
Reaction score
49
Points
28
Location
Los Angeles, CA
Vehicle Year
1989
Make / Model
Ford
Engine Size
2.9L V6
Transmission
Manual
Is there something else I can use?
Napa doesn't have heat sink.
I don't think so. The whole point of it is to conduct heat off the tfi module and onto the distributor. I'm not sure if anything else can transfer the heat properly, and there's a chance it could overheat.

Do you have an AutoZone nearby? That's the only place I could find it.
 

Paulos

Active member
Joined
May 7, 2018
Messages
326
Reaction score
134
Points
43
Location
North Carolina
Vehicle Year
1987 STX
Make / Model
Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Just get dielectric grease. They should have that. The argument of what is best to use will continue until the end of time. I personally have a hard time believing that the distributor runs cooler than the ignition module, which would be the whole purpose of using heat sink grease/paste/TIM. If the distributor is hotter, you will be transferring heat from the distributor to the module. I'm using dielectric grease on mine; no issues.
 

Alaska Diesel

Member
Joined
Sep 22, 2019
Messages
52
Reaction score
8
Points
8
Location
Palmer Ak
Vehicle Year
1986, 1987
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
No I don't have an autozone nearby.
I'll just use dielectric grease thanks.
 

Locotomb

Active member
Joined
Jul 26, 2017
Messages
114
Reaction score
51
Points
28
Location
Puyallup, WA
Vehicle Year
1988, 1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Engine Size
351w
Transmission
Automatic
2WD / 4WD
2WD
Total Lift
6inch custom fab lift/86
Total Drop
3 inch drop beams/88
Tire Size
35/12.5/r18
My credo
Fords and Drums
The grease also ensures a good ground for the module. I am under the impression that heat sink IS dielectric grease. Unless you go to the parts store. They try to sell petroleum jelly as dielectric grease. Which its not. It is good for connectors and spark plug wires but doesn't transfer heat properly. Its freeking Vasoline.
 


Top