new PFC idle sticking problem solving strategy (ISC installed)
08-14-09, 02:39 PM
#26
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well, i thought it was only acting up when it was cold but i drove it for the last two days and it stall even when the water temp is 95c.
my setting are
850
850 EL
950 A/C
F/C speeds to
1100
1100 EL
1150 A/C
my setting are
850
850 EL
950 A/C
F/C speeds to
1100
1100 EL
1150 A/C
08-14-09, 02:56 PM
#27
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Okay here's an update, I was looking around and noticed my tps is unplugged. When I plug it in it like to stall when I let off the gas.
2mm seals
half bridgeport
1600/850
single t-62
power fc
2mm seals
half bridgeport
1600/850
single t-62
power fc
08-14-09, 09:38 PM
#28
09-01-09, 12:16 AM
#30
one thing I want to throw out here: loosening the dashpot to the point where it has no effect on the throttle shouldn't necessarily be done on every single car. It's one of those things you have to fiddle with. Careful adjustment of the dashpot can help fix stalling problems when parking etc. because there are so many different combinations of porting as well as throttlebody settings and clutch/flywheel combos, there is no one surefire way to get your car to idle perfect. Sometimes the dashpot is helpful, and sometimes it causes problems.
08-07-10, 12:44 AM
#32
Red box.
For the sticking idle you adjust things in this basic order, trying them one at a time:
1) air adjusting screw under the TB (close it all the way and then back it out anywhere from 1/4 to 1 full turn).
2) lower fuel cut settings "F/C" under PFC rev/idle screen (red box in the pic above)
3) adjust dashpot on throttlebody--loosen the locknut and rotate it away some
4) lower the idle speed settings under PFC rev/idle screen (green box in the pic above).
It may take some combination of all four approaches. Also note that idle behavior does change with the weather some... you may have to tinker with it a couple times so that it's at a happy medium which won't flake out on you too much as the seasons come and go. You can also try re learning the idle but in my experience that doesn't help the sticking problem very much. It's kind of a dead end for solving that.
For the sticking idle you adjust things in this basic order, trying them one at a time:
1) air adjusting screw under the TB (close it all the way and then back it out anywhere from 1/4 to 1 full turn).
2) lower fuel cut settings "F/C" under PFC rev/idle screen (red box in the pic above)
3) adjust dashpot on throttlebody--loosen the locknut and rotate it away some
4) lower the idle speed settings under PFC rev/idle screen (green box in the pic above).
It may take some combination of all four approaches. Also note that idle behavior does change with the weather some... you may have to tinker with it a couple times so that it's at a happy medium which won't flake out on you too much as the seasons come and go. You can also try re learning the idle but in my experience that doesn't help the sticking problem very much. It's kind of a dead end for solving that.
08-07-10, 11:58 AM
#33
Red box.
For the sticking idle you adjust things in this basic order, trying them one at a time:
1) air adjusting screw under the TB (close it all the way and then back it out anywhere from 1/4 to 1 full turn).
2) lower fuel cut settings "F/C" under PFC rev/idle screen (red box in the pic above)
3) adjust dashpot on throttlebody--loosen the locknut and rotate it away some
4) lower the idle speed settings under PFC rev/idle screen (green box in the pic above).
It may take some combination of all four approaches. Also note that idle behavior does change with the weather some... you may have to tinker with it a couple times so that it's at a happy medium which won't flake out on you too much as the seasons come and go. You can also try re learning the idle but in my experience that doesn't help the sticking problem very much. It's kind of a dead end for solving that.
For the sticking idle you adjust things in this basic order, trying them one at a time:
1) air adjusting screw under the TB (close it all the way and then back it out anywhere from 1/4 to 1 full turn).
2) lower fuel cut settings "F/C" under PFC rev/idle screen (red box in the pic above)
3) adjust dashpot on throttlebody--loosen the locknut and rotate it away some
4) lower the idle speed settings under PFC rev/idle screen (green box in the pic above).
It may take some combination of all four approaches. Also note that idle behavior does change with the weather some... you may have to tinker with it a couple times so that it's at a happy medium which won't flake out on you too much as the seasons come and go. You can also try re learning the idle but in my experience that doesn't help the sticking problem very much. It's kind of a dead end for solving that.
03-07-11, 12:30 PM
#34
Bump for an informative post.
I recently went through this process after setting my idle. I was having the idle sticking problems so I followed arghx's process to fix the sticking but I ran into some problems.
After setting the idle at 850 and going through the learning process I started adjusting the "F/C" settings. I was able to get the sticking to go away while sitting and blipping the throttle, but once I went for a drive around the block the idle would stick again... regardless of "F/C" setting. After lots of adjusting with no luck I decided to check my throttle body adjustments one more time. Turns out I had my AAS adjusted at about 1 full turn from closed. I turned it in to about 1/2 turn from closed and re-learned my idle. Sure enough, that did the trick. I was then able to use the "F/C" settings to permanently tune out the idle sticking issue.
My final settings ended up being:
850
950 EL
950 A/C
F/C speeds to
1150
1150 EL
1150 A/C
Car has a street port w/ 3mm seals, stock twins (NS), and 550/1680 injectors using an FJO driver.
For anyone else working on an idle sticking issue, be sure not to overlook throttle body adjustments.
Arghx, my car thanks you for all your informative posts regarding drive-ability. Your posts have helped me countless times to fix annoying issues regarding my tune that most other people overlook.
I recently went through this process after setting my idle. I was having the idle sticking problems so I followed arghx's process to fix the sticking but I ran into some problems.
After setting the idle at 850 and going through the learning process I started adjusting the "F/C" settings. I was able to get the sticking to go away while sitting and blipping the throttle, but once I went for a drive around the block the idle would stick again... regardless of "F/C" setting. After lots of adjusting with no luck I decided to check my throttle body adjustments one more time. Turns out I had my AAS adjusted at about 1 full turn from closed. I turned it in to about 1/2 turn from closed and re-learned my idle. Sure enough, that did the trick. I was then able to use the "F/C" settings to permanently tune out the idle sticking issue.
My final settings ended up being:
850
950 EL
950 A/C
F/C speeds to
1150
1150 EL
1150 A/C
Car has a street port w/ 3mm seals, stock twins (NS), and 550/1680 injectors using an FJO driver.
For anyone else working on an idle sticking issue, be sure not to overlook throttle body adjustments.
Arghx, my car thanks you for all your informative posts regarding drive-ability. Your posts have helped me countless times to fix annoying issues regarding my tune that most other people overlook.
03-07-11, 03:45 PM
#36
I made this thread a while ago and there are a couple things I've figured out since then, which I will explain briefly.
If you have a Datalogit, the ISC valve duty cycle can in fact be logged. The parameter is Advance "??? (2)" . Units are 0-1000, where 1000 appears to be 100% duty cycle and 0 is 0 duty cycle. So a value of 500 would be 50% duty cycle.
After observing ISC valve duty behavior in this and in the Nissan Sylvia SR20DET Power FC's, I have come to the conclusion that the "F/C" settings have a greater effect on the igniting timing logic than I realized. The SR20DET idle control system is almost identical to the FD's.
Often when you encounter a sticking idle problem, you will see that the throttle is closed, the ISC duty is relatively low, yet the timing is high. Timing control is part of the electronic dashpot logic. These are general observations however. As many of you have found out, the air adjusting screw, engine vacuum, throttle plate opening angle, and other factors still play a big role.
If you have a Datalogit, the ISC valve duty cycle can in fact be logged. The parameter is Advance "??? (2)" . Units are 0-1000, where 1000 appears to be 100% duty cycle and 0 is 0 duty cycle. So a value of 500 would be 50% duty cycle.
After observing ISC valve duty behavior in this and in the Nissan Sylvia SR20DET Power FC's, I have come to the conclusion that the "F/C" settings have a greater effect on the igniting timing logic than I realized. The SR20DET idle control system is almost identical to the FD's.
Often when you encounter a sticking idle problem, you will see that the throttle is closed, the ISC duty is relatively low, yet the timing is high. Timing control is part of the electronic dashpot logic. These are general observations however. As many of you have found out, the air adjusting screw, engine vacuum, throttle plate opening angle, and other factors still play a big role.
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