Gary Lewis Posted July 14, 2020 Share Posted July 14, 2020 From the picture I can see they've already installed a filter before the pump. It looks rather dark(dirty) though... And if it's only recently been done, then the tank might be nasty? You are right, Rob. I missed that. But it is hard to tell if it is really dirty or not as some of the filter elements are dark to start with. My issue with flushing a tank is that gasoline is fairly expensive and it doesn't take wasting much of it to account for an appreciable portion of the cost of a new tank. So maybe pour the old out, swishing the last bits of it around in the tank briskly, and see what you get? If there's much rust I'd opt for a new tank. Link to comment Share on other sites More sharing options...
1986F150Six Posted July 14, 2020 Share Posted July 14, 2020 As for the lack of power, I think that the truck may have the EEC-III system that controls engine timing and even the air/fuel ratio. And depending on what all they did they may have triggered limp-home mode on the ECU. Basically in that mode the ECU locks the timing to base or initial, meaning there is no advance. That kills power and economy. You can covert from what I suspect is the TFI ignition to the more simple DS-II ignition with not much trouble and that will eliminate the ECU. Or, if what they did can be put back, you may get it going again. Unless the Bronco was specified for California, the feedback system began in 1984 for the 4.9L engine. I believe the OP is looking at a 1983. Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 14, 2020 Share Posted July 14, 2020 As for the lack of power, I think that the truck may have the EEC-III system that controls engine timing and even the air/fuel ratio. And depending on what all they did they may have triggered limp-home mode on the ECU. Basically in that mode the ECU locks the timing to base or initial, meaning there is no advance. That kills power and economy. You can covert from what I suspect is the TFI ignition to the more simple DS-II ignition with not much trouble and that will eliminate the ECU. Or, if what they did can be put back, you may get it going again. Unless the Bronco was specified for California, the feedback system began in 1984 for the 4.9L engine. I believe the OP is looking at a 1983. Good point, David. Link to comment Share on other sites More sharing options...
FrazerJames Posted July 14, 2020 Author Share Posted July 14, 2020 Good point, David. This is going to be so much fun to fix up. Right now I have a long list in my head of things to do that I’m simply going to need to write out and prioritize. Sounds like (after getting it running and changing fluids), ignition and alternator are my first Mechanical priorities to upgrade. Anyone have any recommendations for second? I’m sure there’s a list somewhere but my search is not coming up with anything that is succinct although I imagine there are some opinions involved. Link to comment Share on other sites More sharing options...
1986F150Six Posted July 14, 2020 Share Posted July 14, 2020 This is going to be so much fun to fix up. Right now I have a long list in my head of things to do that I’m simply going to need to write out and prioritize. Sounds like (after getting it running and changing fluids), ignition and alternator are my first Mechanical priorities to upgrade. Anyone have any recommendations for second? I’m sure there’s a list somewhere but my search is not coming up with anything that is succinct although I imagine there are some opinions involved. Check everything, since it has been sitting so long! Don't take anything for granted. It will be a fun project! Link to comment Share on other sites More sharing options...
FrazerJames Posted July 14, 2020 Author Share Posted July 14, 2020 Check everything, since it has been sitting so long! Don't take anything for granted. It will be a fun project! That’s definitely the plan! I realize that I didn’t make it very clear that I was asking if there’s a list of upgrades that should be performed either for safety, reliability or performance improvements? Link to comment Share on other sites More sharing options...
85lebaront2 Posted July 14, 2020 Share Posted July 14, 2020 As for the lack of power, I think that the truck may have the EEC-III system that controls engine timing and even the air/fuel ratio. And depending on what all they did they may have triggered limp-home mode on the ECU. Basically in that mode the ECU locks the timing to base or initial, meaning there is no advance. That kills power and economy. You can covert from what I suspect is the TFI ignition to the more simple DS-II ignition with not much trouble and that will eliminate the ECU. Or, if what they did can be put back, you may get it going again. Unless the Bronco was specified for California, the feedback system began in 1984 for the 4.9L engine. I believe the OP is looking at a 1983. 1983 could have had the MCU system, and probably does. MCU = Mixture Control Unit and was made in both a CA spec and 49 state spec. EEC-III was never on the 300. 1984 is when the feedback carbs started and those systems are EEC-IV and do use the TFI ignition module. All my emission diagrams show either a single or dual diaphragm distributor which points toward a DS-II ignition. What I can get from my AllData is the MCU sits on top of the DS-II (or possibly DS-III) and there should be some vacuum switches on the top rear of the valve cover. I can pull up the MCU wiring, but the ignition diagrams say "without EEC" but Ford does not call this system an EEC so it may be correct, in which case it is the DS-II system which is usually pretty damn reliable. In the bottom right of the picture Gary enlarged, there appears to be a box with an electrical connector on top, if so it should be 24 pins and will be the MCU, under it should be the DS-II box. Link to comment Share on other sites More sharing options...
FrazerJames Posted July 14, 2020 Author Share Posted July 14, 2020 1983 could have had the MCU system, and probably does. MCU = Mixture Control Unit and was made in both a CA spec and 49 state spec. EEC-III was never on the 300. 1984 is when the feedback carbs started and those systems are EEC-IV and do use the TFI ignition module. All my emission diagrams show either a single or dual diaphragm distributor which points toward a DS-II ignition. What I can get from my AllData is the MCU sits on top of the DS-II (or possibly DS-III) and there should be some vacuum switches on the top rear of the valve cover. I can pull up the MCU wiring, but the ignition diagrams say "without EEC" but Ford does not call this system an EEC so it may be correct, in which case it is the DS-II system which is usually pretty damn reliable. In the bottom right of the picture Gary enlarged, there appears to be a box with an electrical connector on top, if so it should be 24 pins and will be the MCU, under it should be the DS-II box. That’s some great detective work, Bill! Just taking that in, it sounds like you’re saying there’s not necessarily any upgrade to be made there that will improve anything dramatically. Assuming the DS-II box is there. I’m going to see it Saturday. I’ll make sure to take a bunch of pics if I can’t drive it home. Link to comment Share on other sites More sharing options...
1986F150Six Posted July 14, 2020 Share Posted July 14, 2020 That’s some great detective work, Bill! Just taking that in, it sounds like you’re saying there’s not necessarily any upgrade to be made there that will improve anything dramatically. Assuming the DS-II box is there. I’m going to see it Saturday. I’ll make sure to take a bunch of pics if I can’t drive it home. Make sure the photos include close-ups of the distributor base as well as the driver side fender liner. Link to comment Share on other sites More sharing options...
grumpin Posted July 16, 2020 Share Posted July 16, 2020 Ah! Is that what that brown thing is in the line? I suppose sitting for 12 years could do that... I wonder if I just drop the tank and clean it out, if that’ll do it. Welcome! Link to comment Share on other sites More sharing options...
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