1986 Ranger runs rough cold

[Alaska Diesel]

I tried it in a different browser than Google Chrome and it worked.
I used Microsoft Edge

 

[Locotomb]

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]

I have another ECM that is good I've put that on it and it's still the same.

 

[Locotomb]

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.

 

[Alaska Diesel]

How would I test the TFI?
The TFI is on the distributor right?

 

[Locotomb]

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]

Ok thanks.

 

[Alaska Diesel]

I have an extra TFI module. What kind of grease is supposed to be used on it?

 

[Nez'sRanger]

I have an extra TFI module. What kind of grease is supposed to be used on it?

Heat sink grease. Don't use the dielectric grease.

 

[Alaska Diesel]

Ok thanks, I knew it was something different the dielectric grease.

 

[Alaska Diesel]

Is there something else I can use?
Napa doesn't have heat sink.

 

[Nez'sRanger]

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]

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]

No I don't have an autozone nearby.
I'll just use dielectric grease thanks.

 

[Locotomb]

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.