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Something keeps smoking up in 1985 ranger.


85rngr4x4

Active Member
Joined
Jun 11, 2023
Messages
31
City
Ohio
Vehicle Year
1986
Transmission
Automatic
I’ve got a 1985 ranger 2.8 cologne and it seems to have a problem at full throttle where a relay mounted near the pcm in the passenger side keeps smoking. I thought it was a wire but after fixing that it did it again. Relay feels hot to the touch and smells bad, but visually looks ok. Any ideas?
image.jpg


image.jpg

I repaired the blue wire.
 
What does the plug look like where the relay plugs in? What does the relay prongs look like where the plug plugs into the relay? If there is any melting, you need a new relay and a new plug-in. Poor loose connections cause heat and smoking. Melted plastic that holds the metal prongs make the problem worse,, they do not hold the relay prongs and the plug-ins in the plug tight.
 
Thanks for the info, I’ll have to go take a look
 
Does the truck have AC?

If it only does it at WOT id say its the AC cut out relay.

Try replacing the relay
 
There is a lot of junk over there on an original 2.8 unit. There was a relay over there for the choke, among other things. I can't look and see now, I took it all out :)
 
I think the relay is directly tied to the pcm or tfi in some way, because whenever smokes out and dies, it make the truck loose power past 35mph.
 
I think the relay is directly tied to the pcm or tfi in some way, because whenever smokes out and dies, it make the truck loose power past 35mph.
I would do the conversion if you can find a distributor for it and get rid of all that stuff.
 
I’ll have to look into the a/c, I never even considered that. I also do plan on doing the conversion, I just have to find the parts for it. If I can figure out what my problem is then I’ll probably end up doing it soon.
 
I’ll have to look into the a/c, I never even considered that. I also do plan on doing the conversion, I just have to find the parts for it. If I can figure out what my problem is then I’ll probably end up doing it soon.
If you can find a distributor, the rest is easy. I am using a china knock-off carb on mine from ebay. Thing is, the conversion would most likely make your problem go away. Conversion means no relay, which would mean it can't smoke anymore if it's not there.
 
Duraspark 2.8 distributors are basically impossible to come by now...atleast from what ive seen on here.

2150's are as plentiful as dirt
 
Does the truck have AC?

If it only does it at WOT id say its the AC cut out relay.

Try replacing the relay

A/C cutout is on the inner fender in the engine bay.

Looks like it is the relay for the ECM.



There is a choke relay but it is under the hood.





Now the question of the day is if the relay getting hot is the problem or a symptom...
 
I once heard where there's smoke there's fire. Be careful with that mess man
 
I think the relay is directly tied to the pcm or tfi in some way, because whenever smokes out and dies, it make the truck loose power past 35mph.
Since it is the ECM relay, you probably are losing power to the ECM. The TFI has a limp mode where if the computer control is gone, it reverts to static timing which will lock it at 10 BTDC but still produce spark to keep the engine running.

These vehicles were old school, priority was to get you home if they could. Unlike now, if some sort of stupid emissions part fails, the vehicle quits in 50 miles.
 
Since it is the ECM relay, you probably are losing power to the ECM. The TFI has a limp mode where if the computer control is gone, it reverts to static timing which will lock it at 10 BTDC but still produce spark to keep the engine running.

These vehicles were old school, priority was to get you home if they could. Unlike now, if some sort of stupid emissions part fails, the vehicle quits in 50 miles.
Thats why I was pretty sure it was the eec relay, because it was in limp mode.
 
A/C cutout is on the inner fender in the engine bay.

Looks like it is the relay for the ECM.



There is a choke relay but it is under the hood.





Now the question of the day is if the relay getting hot is the problem or a symptom...
I’m not sure if it’s the relay itself or if the blue fusible wire that connects to those vacuum sensors and stuff is shorted. Would you have any idea where that wire would branch off? I’d prefer to not have to cut open the whole harness to search for them if anyone would already know.
IMG_3802.jpeg

It’s just the blue part of the wire that burns up. The red part of the wire past the insulator is undamaged as far as I can tell.
 

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