Gary Lewis Posted April 19, 2020 Share Posted April 19, 2020 It is my understanding that there is only 1 O2 sensor right? Just want to make sure before I get the part. Yes, the 1985 EFI system only has one O2 sensor. The one shown below: Link to comment Share on other sites More sharing options...
railwayboiii Posted April 22, 2020 Author Share Posted April 22, 2020 Yes, the 1985 EFI system only has one O2 sensor. The one shown below: The "Unscrewing" continues... My new solenoid cluster came in with attached vacuum lines in tow. Upon a slight brushing of the lines, *snap!* They were brittle and bad. Curses were said, and beers were had. The next day, today, I went to Autozone to get soft line and connectors to make my own piping so this didn't happen again. After a hour of assembly, the lines came together like a dream and I was finally able to test the new part and see what it would do to the truck. I literally can not believe it, low and behold it runs WORSE! Not only does it run even RICHER, the engine isn't keeping a steady idle as it was before, even dying during the first 2 times. I have no clue what to do now, besides go on with the O2 replacement and new spark plugs, and pray the O2 sensor is just super bad. I feel like I should mention that I should put on new pigtails, the wires are exposed due to rot, but I have no clue if this would affect it THIS bad. I will also add that the engine ran this way before I replaced the MAP sensor, so now I am just double lost. I hear a clicking sound somewhere in the engine bay which sounds to me like a short, but I have no idea where and all of the fuses in the fuse box came back OK. The only thing I can think of is something related to the EGR, at this point, it has been the only thing I haven't touched. What are your first thoughts? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted April 22, 2020 Share Posted April 22, 2020 The "Unscrewing" continues... My new solenoid cluster came in with attached vacuum lines in tow. Upon a slight brushing of the lines, *snap!* They were brittle and bad. Curses were said, and beers were had. The next day, today, I went to Autozone to get soft line and connectors to make my own piping so this didn't happen again. After a hour of assembly, the lines came together like a dream and I was finally able to test the new part and see what it would do to the truck. I literally can not believe it, low and behold it runs WORSE! Not only does it run even RICHER, the engine isn't keeping a steady idle as it was before, even dying during the first 2 times. I have no clue what to do now, besides go on with the O2 replacement and new spark plugs, and pray the O2 sensor is just super bad. I feel like I should mention that I should put on new pigtails, the wires are exposed due to rot, but I have no clue if this would affect it THIS bad. I will also add that the engine ran this way before I replaced the MAP sensor, so now I am just double lost. I hear a clicking sound somewhere in the engine bay which sounds to me like a short, but I have no idea where and all of the fuses in the fuse box came back OK. The only thing I can think of is something related to the EGR, at this point, it has been the only thing I haven't touched. What are your first thoughts? I think the clicking is the solenoids opening and closing. Is there a diagnostic in the EVTM? Link to comment Share on other sites More sharing options...
railwayboiii Posted April 23, 2020 Author Share Posted April 23, 2020 I think the clicking is the solenoids opening and closing. Is there a diagnostic in the EVTM? I'm actually dumb, I kicked off the ignition coil lead to the distributor while working on it! Put it back on, runs much better, solid idle, but still rich. We'll see what happens post O2. Link to comment Share on other sites More sharing options...
swampedout Posted April 23, 2020 Share Posted April 23, 2020 I'm actually dumb, I kicked off the ignition coil lead to the distributor while working on it! Put it back on, runs much better, solid idle, but still rich. We'll see what happens post O2. Nice looking truck! Its always frustrating in the beginning but youll work all the little problems out. Early EFI systems can be confusing but its worth trying to pull codes on it. Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 23, 2020 Share Posted April 23, 2020 I'm actually dumb, I kicked off the ignition coil lead to the distributor while working on it! Put it back on, runs much better, solid idle, but still rich. We'll see what happens post O2. I think those happenings are meant to keep us humble. Happens to me all the time. Glad you found it! Link to comment Share on other sites More sharing options...
railwayboiii Posted May 27, 2020 Author Share Posted May 27, 2020 I think the clicking is the solenoids opening and closing. Is there a diagnostic in the EVTM? THE UNSCREWING CONTINUES! I am not dead! Significant work was accomplished this week, after a seized O2 sensor and exhaust leak were discovered, new piping, manifolds, a CAT, and new plugs and a O2 sensor were installed. One dang thing after another though! At first, it sounded good until, the engine's idle just got higher and HIGHER AND HIGHER!!! I literally have NO clue where to start with this! It isn't even going down! It never did this before the work was done on it! Any ideas?! Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted May 27, 2020 Share Posted May 27, 2020 THE UNSCREWING CONTINUES! I am not dead! Significant work was accomplished this week, after a seized O2 sensor and exhaust leak were discovered, new piping, manifolds, a CAT, and new plugs and a O2 sensor were installed. One dang thing after another though! At first, it sounded good until, the engine's idle just got higher and HIGHER AND HIGHER!!! I literally have NO clue where to start with this! It isn't even going down! It never did this before the work was done on it! Any ideas?! Intake leak? IAC? Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 27, 2020 Share Posted May 27, 2020 Intake leak? IAC? Yes, it could be either an intake leak or the idle air controller. But, the fact that it is getting worse, meaning the idle is getting higher, suggests that something is leaking progressively more and more. I wouldn't think an intake leak would do that. But the IAC might. Or a vacuum hose may have cracked and be getting worse? But, it could also be a throttle position sensor. And let's explain what appears to be going on. The EFI system wants the air/fuel mix to be about 14:1. And, it wants the idle to be ~650 RPM. However, it takes its cue for RPM from the throttle position sensor. So if the TPS, or the throttle itself, isn't going back to idle then the computer thinks that you want a higher RPM than idle and adjusts the IAC and the fuel injector pulses accordingly. But if the TPS is going back to idle and yet there's a vacuum leak the computer will add fuel to keep the air/fuel ratio at 14:1, which increases the RPM. Adjustment of the idle speed is shown on Page 74 here: http://www.garysgaragemahal.com/1985-1986-fuel-system-adjustments.html Perhaps a better description of adjusting the idle speed is given on Page 168 here: http://www.garysgaragemahal.com/efi-idle-speed-adjustment.html And a description of the system is given here, although you probably don't need that: http://www.garysgaragemahal.com/efi.html Link to comment Share on other sites More sharing options...
85lebaront2 Posted May 28, 2020 Share Posted May 28, 2020 Yes, it could be either an intake leak or the idle air controller. But, the fact that it is getting worse, meaning the idle is getting higher, suggests that something is leaking progressively more and more. I wouldn't think an intake leak would do that. But the IAC might. Or a vacuum hose may have cracked and be getting worse? But, it could also be a throttle position sensor. And let's explain what appears to be going on. The EFI system wants the air/fuel mix to be about 14:1. And, it wants the idle to be ~650 RPM. However, it takes its cue for RPM from the throttle position sensor. So if the TPS, or the throttle itself, isn't going back to idle then the computer thinks that you want a higher RPM than idle and adjusts the IAC and the fuel injector pulses accordingly. But if the TPS is going back to idle and yet there's a vacuum leak the computer will add fuel to keep the air/fuel ratio at 14:1, which increases the RPM. Adjustment of the idle speed is shown on Page 74 here: http://www.garysgaragemahal.com/1985-1986-fuel-system-adjustments.html Perhaps a better description of adjusting the idle speed is given on Page 168 here: http://www.garysgaragemahal.com/efi-idle-speed-adjustment.html And a description of the system is given here, although you probably don't need that: http://www.garysgaragemahal.com/efi.html Ok, a few items from dealing with my son's 1986 F150 EFI 302. First, the 1985/86 EFI system uses the TPS voltage as the idle set point, not rpm. The set point is pretty sensitive as it is 1.0 VDC +/- .05 VDC. This is critical as the EGR controls start at 1.10 VDC and too much throttle opening will cause a solenoid "chatter" or a surging idle as the EGR opens than closes. The 1987 up systems use a "duty cycle" solenoid rather than the Vacuum/Vent system in 85-86. The wiring harnesses on these were also horrible quality, frayed insulation to the point of shorts and grounds. I was able to retrieve the harness(s) I had obtained for him and have perfect set of solenoids for the system. I will not be able really lay these out and do a full inspection/photos until probably 1 June as I am not at home nor will be till Sunday afternoon at the earliest. Link to comment Share on other sites More sharing options...
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