ReneH Posted March 15, 2023 Share Posted March 15, 2023 Hi together, while wating for my resistors for the emissions control, I'll checked my TPS...that's what I've got: Throttle opening by idle screw of 0,3mm (0.0118") Closed throttle value of the TPS: Fully opened value of the TPS: As far as I know the TPS values are in range. About the closed throttle opening I'm not sure...I don't find a value for this... Another question: I use an IAC from a 1990th truck...for what the hell is this black plastic cap? Something for adjustment? Link to comment Share on other sites More sharing options...
mat in tn Posted March 16, 2023 Share Posted March 16, 2023 i would back the throttle screw down a little more to get a little further from the 1 volt setting at least until other tuning points are corrected. only creep up on the 1v value while all else is good. Link to comment Share on other sites More sharing options...
85lebaront2 Posted March 16, 2023 Share Posted March 16, 2023 i would back the throttle screw down a little more to get a little further from the 1 volt setting at least until other tuning points are corrected. only creep up on the 1v value while all else is good. Good point, since he isn't using the 1986 ECU, it shouldn't be as sensitive to not being very close to 1 volt. Link to comment Share on other sites More sharing options...
ReneH Posted March 16, 2023 Author Share Posted March 16, 2023 i would back the throttle screw down a little more to get a little further from the 1 volt setting at least until other tuning points are corrected. only creep up on the 1v value while all else is good. Ok...so if I turn the screw a bit more out, also the plates will close more. Is there no mechanical closed throttle distance value for the base setup? I also can change the TPS closed value by loosen the screws and turning the TPS some degrees... And what's about the IAC plastic cap? Before installing I have tried to carefully remove it, cause I thought there may something below...but I can only turn it... So as I don't know what it is, I may have misaligned something... Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 16, 2023 Share Posted March 16, 2023 Ok...so if I turn the screw a bit more out, also the plates will close more. Is there no mechanical closed throttle distance value for the base setup? I also can change the TPS closed value by loosen the screws and turning the TPS some degrees... And what's about the IAC plastic cap? Before installing I have tried to carefully remove it, cause I thought there may something below...but I can only turn it... So as I don't know what it is, I may have misaligned something... I hate to jump in here as you've been getting good advice and I don't want to slow the others down. But you need to have the throttles closed enough that the IAC is in the middle of its range so the ECU can adjust properly. And that takes some throttle opening, so you don't want to close the throttle too much. Maybe try turning the TPS a bit to drop the voltage? As for the plastic thing, I don't know what it is, but lots of IAC's have it. And it spins but doesn't do anything. Link to comment Share on other sites More sharing options...
mat in tn Posted March 16, 2023 Share Posted March 16, 2023 I hate to jump in here as you've been getting good advice and I don't want to slow the others down. But you need to have the throttles closed enough that the IAC is in the middle of its range so the ECU can adjust properly. And that takes some throttle opening, so you don't want to close the throttle too much. Maybe try turning the TPS a bit to drop the voltage? As for the plastic thing, I don't know what it is, but lots of IAC's have it. And it spins but doesn't do anything. I cannot say for certain as many have this cap but not all brands. if I were to guess given its design and position it is the cover for a vented solenoid to prevent condensation from forming. no adjustments here. also there are two basic types of iac's. one which most trucks that i have seen use which uses a spool valve through a tunnel design and the plunger design which lifts a valve on and off of a seat to adjust needed air trim. I have seen both used many times and i have seen cases where one controls better than the other. just experience and I'm still sorting out the how's and whys. maybe a good discussion. Idk. Link to comment Share on other sites More sharing options...
ReneH Posted March 16, 2023 Author Share Posted March 16, 2023 I hate to jump in here as you've been getting good advice and I don't want to slow the others down. But you need to have the throttles closed enough that the IAC is in the middle of its range so the ECU can adjust properly. And that takes some throttle opening, so you don't want to close the throttle too much. Maybe try turning the TPS a bit to drop the voltage? As for the plastic thing, I don't know what it is, but lots of IAC's have it. And it spins but doesn't do anything. Hey Gary, I think you won't slow down the others. It's good to get different experiences together in my mind. Ok, so there is no distance value of the plate to the throttle body given by ford? Interesting...how have they made the setup after installing the plates... About my IAC...one from FSB told me that the type I currently use maybe doesn't needs the diode anymore...could this be? So when my IAC not moving, maybe cause of the diode, it also can explain why the engine only starts with unplugged vacuum hose... Is there a way to check if the IAC works without unmounted it? Link to comment Share on other sites More sharing options...
85lebaront2 Posted March 16, 2023 Share Posted March 16, 2023 Hey Gary, I think you won't slow down the others. It's good to get different experiences together in my mind. Ok, so there is no distance value of the plate to the throttle body given by ford? Interesting...how have they made the setup after installing the plates... About my IAC...one from FSB told me that the type I currently use maybe doesn't needs the diode anymore...could this be? So when my IAC not moving, maybe cause of the diode, it also can explain why the engine only starts with unplugged vacuum hose... Is there a way to check if the IAC works without unmounted it? The diode, is wired as a "snubbing" device, it is connected so a voltage "spike" caused when power is shut off to a solenoid is dumped through the diode, but in normal usage it is an open circuit. Essentially and electronic check valve. Link to comment Share on other sites More sharing options...
ReneH Posted March 16, 2023 Author Share Posted March 16, 2023 The diode, is wired as a "snubbing" device, it is connected so a voltage "spike" caused when power is shut off to a solenoid is dumped through the diode, but in normal usage it is an open circuit. Essentially and electronic check valve. Hi Bill, Ok, thanks. So if nobody knows the factory opening of the throttle plate, I have to figure it out. Regarding the IAC testing I will unmount it to check if it moves... My resistors haven't arrived me today, so I hope I will get them tomorrow. I will open another thread with the things left to do on my bronco...I have some urgent and also some secondary aims. So you can see, what's left. I also will post my progress there. For the open questions or problems, i will open a thread for each them. I hope this acting will not declared as spam... Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 16, 2023 Share Posted March 16, 2023 Hi Bill, Ok, thanks. So if nobody knows the factory opening of the throttle plate, I have to figure it out. Regarding the IAC testing I will unmount it to check if it moves... My resistors haven't arrived me today, so I hope I will get them tomorrow. I will open another thread with the things left to do on my bronco...I have some urgent and also some secondary aims. So you can see, what's left. I also will post my progress there. For the open questions or problems, i will open a thread for each them. I hope this acting will not declared as spam... Your posts won't be considered spam, so don't worry. On the throttle opening, I don't think there is a specified one. But it isn't an exact science. You need enough throttle opening so the IAC isn't running 100% duty cycle or the IAC may burn out and the ECU won't be able to control very well. On the other hand, if you have too much throttle opening and the IAC doesn't have to run at all then the ECU will be hampered on that end as well. So if I were you I'd get things working pretty well and then start playing with throttle opening. I'd use my DVM to infer duty cycle on the IAC since if you see battery voltage when on the DC scale you know you have 100% duty cycle, and zero voltage means you have 0% duty cycle. And I'd shoot for something in the 30 - 40% range. Link to comment Share on other sites More sharing options...
Recommended Posts