Starliner Posted May 2, 2020 Share Posted May 2, 2020 I'm not sure if this should be connected or not. These plugs are right near the ICM. Any guesses out there? I'm banging my head trying to sniff out rough idle issue so I wanted to cover all bases. After sitting in dry climate for 10 years, I replaced: ICM, Coil, plugs, wires, cap, rotor, most vac lines, I've blocked off the brake booster, rebuilt the carb, replaced the ignition switch, Still rough. Carb clean isnt helping find a vac leak. Besides idle, the truck runs great. Any ideas would be appreciated. Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 3, 2020 Share Posted May 3, 2020 That looks like one of the connectors to the ignition module. Show me the wire colors? Link to comment Share on other sites More sharing options...
Starliner Posted May 3, 2020 Author Share Posted May 3, 2020 Hi Gary They are green and black. Thanks. Link to comment Share on other sites More sharing options...
Starliner Posted May 3, 2020 Author Share Posted May 3, 2020 Better picture Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 3, 2020 Share Posted May 3, 2020 Better picture The better picture did it. I believe you are looking at C169, and those are the two wires going to the tach. See the right side of the first page below, from the 1985 EVTM, that shows the wire colors, and the second page that shows where the connector is, its color, and the # of pins. Link to comment Share on other sites More sharing options...
Starliner Posted May 3, 2020 Author Share Posted May 3, 2020 The better picture did it. I believe you are looking at C169, and those are the two wires going to the tach. See the right side of the first page below, from the 1985 EVTM, that shows the wire colors, and the second page that shows where the connector is, its color, and the # of pins. Ok, I see it there. Since I dont have a tach, I guess it is normal for that to be disconnected. Do you thing there is any downside to plugging it in? I have to get a factory service manual on CD for sure. Thank you. Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 3, 2020 Share Posted May 3, 2020 Ok, I see it there. Since I dont have a tach, I guess it is normal for that to be disconnected. Do you thing there is any downside to plugging it in? I have to get a factory service manual on CD for sure. Thank you. There's no downside to plugging it in. As for getting the factory service manual, it is a good thing to have. However, those schematics are from the EVTM. But in reality much of the FSM is on-line on the site, and all of the 1981, '85, and '86 EVTM's are. Link to comment Share on other sites More sharing options...
swampedout Posted May 3, 2020 Share Posted May 3, 2020 There's no downside to plugging it in. As for getting the factory service manual, it is a good thing to have. However, those schematics are from the EVTM. But in reality much of the FSM is on-line on the site, and all of the 1981, '85, and '86 EVTM's are. Look up DIY smoke machines. Cheap and easy to make and much more effective than spraying carb cleaner. I cant tell you how many trucks Ive sprayed and figured didnt have leaks even with continued rough idle, only to later smoke them and find the problem in seconds. Link to comment Share on other sites More sharing options...
LARIAT 85 Posted May 3, 2020 Share Posted May 3, 2020 Ok, I see it there. Since I dont have a tach, I guess it is normal for that to be disconnected. Do you thing there is any downside to plugging it in? I have to get a factory service manual on CD for sure. Thank you. Yes, that connector is for a factory tachometer. Plug it in and get yourself a replacement cluster that has a tachometer in it. Link to comment Share on other sites More sharing options...
Starliner Posted May 3, 2020 Author Share Posted May 3, 2020 Yes, that connector is for a factory tachometer. Plug it in and get yourself a replacement cluster that has a tachometer in it. You are all so very helpful, thank you. Of course I will be DYI-ing a smoker right away and will post an update. Link to comment Share on other sites More sharing options...
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