Surging idle. Fix?
03-19-04, 04:48 PM
#1
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Surging idle. Fix?
Before you move this to the PFC forum, please know that I have read every thread in there and tried every method of fixing to no avail.. I figure there might be more response in the 3rd gen forum, although this IS PFC related I believe.
Car: 93 FD
Motor: Lg streetport 13BREW
Turbo: TO4R
Fuel: 850/1680 SX reg, dual walboros @ 12V
ECU: PFC/Commander
Full exhaust, fmic... etc
I have done the learn mode 3 times. I have unplugged the Idle motor from the back of the UIM. I have loaded Chuck Westbrooks fuel maps and relearned the idle.
I've done it all SEVERAL times. No luck. I can't get the goddamn surge to go away.. Ive adjusted the air bleed, the idle screw, and tried a new TPS..
Does ANYONE have any other ideas? I've been fighting this thing for 2 weeks. I must be missing something, but I don't know where to look.
It is my understanding that tuning for the streetport has to be done, but I was under the impression that the maps I loaded (manually I might add) would cure the problem.
I'm on the verge of offering $$ for a fix action, so if you have ideas let me have the.. A running car is worth it to me.
Thanks for the time.
Justin
Car: 93 FD
Motor: Lg streetport 13BREW
Turbo: TO4R
Fuel: 850/1680 SX reg, dual walboros @ 12V
ECU: PFC/Commander
Full exhaust, fmic... etc
I have done the learn mode 3 times. I have unplugged the Idle motor from the back of the UIM. I have loaded Chuck Westbrooks fuel maps and relearned the idle.
I've done it all SEVERAL times. No luck. I can't get the goddamn surge to go away.. Ive adjusted the air bleed, the idle screw, and tried a new TPS..
Does ANYONE have any other ideas? I've been fighting this thing for 2 weeks. I must be missing something, but I don't know where to look.
It is my understanding that tuning for the streetport has to be done, but I was under the impression that the maps I loaded (manually I might add) would cure the problem.
I'm on the verge of offering $$ for a fix action, so if you have ideas let me have the.. A running car is worth it to me.
Thanks for the time.
Justin
03-19-04, 05:12 PM
#2
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It would help if you can discribe how the idle is surging. Is it dropping low to the point of almost dying, is it going high, a better discription would help.
03-19-04, 05:17 PM
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Surging Idle
The following worked for me.
1- Turn the air bleed screw under the elbow all the way in (clockwise) and then back out 1/4 turn.
2- Back out the idle speed adjust screw on the front of the throttle body till it no longer touches. I backed it out untill i saw clearance under the screw, turned it in by hand until I could feel it touch, and then backed out a half a turn. When you tighten the nut to lock it down this adjustment may change. The end result is that you do not want this adjustment doing anything.
3- In the PFC commander set the fuel in cells N1-N4 to P01-P05 as follows. This will smooth the loopy idle.
N1 N2 N3 N4 N5
P01 105 105 100 100 105
P02 105 105 100 100 105
P03 100 100 100 100 105
P04 100 100 100 100 105
P05 105 100 100 100 100
Let me know how you make out. I assume you have the Idle Control Valve still hooked up.
1- Turn the air bleed screw under the elbow all the way in (clockwise) and then back out 1/4 turn.
2- Back out the idle speed adjust screw on the front of the throttle body till it no longer touches. I backed it out untill i saw clearance under the screw, turned it in by hand until I could feel it touch, and then backed out a half a turn. When you tighten the nut to lock it down this adjustment may change. The end result is that you do not want this adjustment doing anything.
3- In the PFC commander set the fuel in cells N1-N4 to P01-P05 as follows. This will smooth the loopy idle.
N1 N2 N3 N4 N5
P01 105 105 100 100 105
P02 105 105 100 100 105
P03 100 100 100 100 105
P04 100 100 100 100 105
P05 105 100 100 100 100
Let me know how you make out. I assume you have the Idle Control Valve still hooked up.
03-19-04, 06:47 PM
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Originally posted by Trexthe3rd
It would help if you can discribe how the idle is surging. Is it dropping low to the point of almost dying, is it going high, a better discription would help.
It would help if you can discribe how the idle is surging. Is it dropping low to the point of almost dying, is it going high, a better discription would help.
03-19-04, 06:50 PM
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Originally posted by ulost2my7
throttle position sensor, isc?
throttle position sensor, isc?
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03-19-04, 08:02 PM
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Do you still have the fuel pressure regulator. This dramatically improved my idle. Also is this when cold or after hot. Because when its cold I have a hard time starting up and get some surge but as it gets hot, it settles down.
03-19-04, 08:51 PM
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After you unplug the Idle Control your idle will not adjust to either ELD or AC loads. The additional load on the engine will cause the idle to decrease as there is no compensation via the ISC. However, this might work if you set the idle high enough, like 900-1000 RPM.
BTW..my idle is rock steady at 750, with the adjustments described above. Also, the behavior is such that the engine speed drops to about 1100 for about 15 seconds before then dropping to 750. At either speed the idle is constant with no hunting or surging. My Idle Control is plugged in.
I am convinced that the issue is to much air. Driving the air bleed screw almost all the way in and shutting the throttle plates as far as they go, certainly reduces this condition. Before I made these adjustments my idle was all over the board as you described, 800-1500.
BTW..my idle is rock steady at 750, with the adjustments described above. Also, the behavior is such that the engine speed drops to about 1100 for about 15 seconds before then dropping to 750. At either speed the idle is constant with no hunting or surging. My Idle Control is plugged in.
I am convinced that the issue is to much air. Driving the air bleed screw almost all the way in and shutting the throttle plates as far as they go, certainly reduces this condition. Before I made these adjustments my idle was all over the board as you described, 800-1500.
Last edited by mklinger; 03-19-04 at 08:58 PM.
03-20-04, 10:08 AM
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Originally posted by clayne
Was the ISC connected when you did the idle learn ?
Was the ISC connected when you did the idle learn ?
03-20-04, 10:09 AM
#14
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Originally posted by Fatman0203
Do you still have the fuel pressure regulator. This dramatically improved my idle. Also is this when cold or after hot. Because when its cold I have a hard time starting up and get some surge but as it gets hot, it settles down.
Do you still have the fuel pressure regulator. This dramatically improved my idle. Also is this when cold or after hot. Because when its cold I have a hard time starting up and get some surge but as it gets hot, it settles down.
03-20-04, 10:10 AM
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Originally posted by RX7WEEE
could be a vacum leak. thats what mine was. it was on the LIM
could be a vacum leak. thats what mine was. it was on the LIM
03-20-04, 10:11 AM
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Originally posted by mklinger
After you unplug the Idle Control your idle will not adjust to either ELD or AC loads. The additional load on the engine will cause the idle to decrease as there is no compensation via the ISC. However, this might work if you set the idle high enough, like 900-1000 RPM.
BTW..my idle is rock steady at 750, with the adjustments described above. Also, the behavior is such that the engine speed drops to about 1100 for about 15 seconds before then dropping to 750. At either speed the idle is constant with no hunting or surging. My Idle Control is plugged in.
I am convinced that the issue is to much air. Driving the air bleed screw almost all the way in and shutting the throttle plates as far as they go, certainly reduces this condition. Before I made these adjustments my idle was all over the board as you described, 800-1500.
After you unplug the Idle Control your idle will not adjust to either ELD or AC loads. The additional load on the engine will cause the idle to decrease as there is no compensation via the ISC. However, this might work if you set the idle high enough, like 900-1000 RPM.
BTW..my idle is rock steady at 750, with the adjustments described above. Also, the behavior is such that the engine speed drops to about 1100 for about 15 seconds before then dropping to 750. At either speed the idle is constant with no hunting or surging. My Idle Control is plugged in.
I am convinced that the issue is to much air. Driving the air bleed screw almost all the way in and shutting the throttle plates as far as they go, certainly reduces this condition. Before I made these adjustments my idle was all over the board as you described, 800-1500.
03-20-04, 02:26 PM
#18
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Originally posted by rfreeman27
Are you sure your IAC is working? I had to take mine out and soak the valve deal in brake cleaner.
Are you sure your IAC is working? I had to take mine out and soak the valve deal in brake cleaner.
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