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Wierd idle fluctuation issue maybe cause by ECU

 
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Old 01-18-2009, 09:57 AM
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Wierd idle fluctuation issue maybe cause by ECU

So lets start out by saying I am running a 4 plug auto P13 ECU in my 5 speed H22 Prelude. The issue is/was when I turn on my heater and or headlights the idle would jump up too far and I would get a bouncy idle which couln't be reversed until I relieved the electrical load. I couldn't set the idle low enough without a load so that it would stay below the 1100 mark with a load (at 1100 and above honda ecu's cut the injectors with the throttle shut for fuel economy) so every time I give it an electrical load I get the bouncy idle.

So after trying most everything humanly possible I grabbed my old Auto P28 that was fake JUN chipped and I removed two resistors and jumped one connection making it a manual ECU. I then plugged it in and started it up, then had to adjust the idle up a ways to get it right. Now when I turn on the headlights/heater it doesn't go crazy with the idle and start bouncing.

Now I am debating if I should sell the auto p13 and get a manual p13 or what? The p28's vtec doesn't kick in till around 6 grand with no rev limiter and is a lot weaker than the p13's vtec although the p28 feels like it pulls harder before vtec than the p13.
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emblems, Stock si wheels atm, Tokico Blues,
Tein lowering springs, MSD Cap
and coil, NGK IRIDIUM IX Spark Plugs, NGK Wires,
6000K Hid's,5 speed swap, fidanza 8lb flywheel,
Walbro 190lph fuel pump, Vtec front brakes,
Powerstop drilled/slotted rotors,
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Vibrant StreetPower Axleback

1993 Impreza
RIP 1990 Nissan 240SX Coupe w/redtop SR20DET
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Last edited by ididdy; 01-18-2009 at 11:02 AM.
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Old 01-18-2009, 05:01 PM
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Re: Wierd idle fluctuation issue maybe cause by ECU

Did you tighten the idle screw like I suggested in the other thread? Mine idled at 1100 too before I tightened it. Now it idles at 750, and I don't have any problems with lights on or whatever.
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Old 01-18-2009, 10:19 PM
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Re: Wierd idle fluctuation issue maybe cause by ECU

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Originally Posted by bdmski View Post
Did you tighten the idle screw like I suggested in the other thread? Mine idled at 1100 too before I tightened it. Now it idles at 750, and I don't have any problems with lights on or whatever.

Yes I have tried that, I had also noticed after removing the TB that the throttle plate wasn't closing completely and fixed that. None of that worked as whenever a load occurs my RPM's would jump up 500 rpm or so. Not with the P28 tho.
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1992 Prelude si 4ws H22A swap
WingsWest Big Mouth Kit,Shaved Handles,
emblems, Stock si wheels atm, Tokico Blues,
Tein lowering springs, MSD Cap
and coil, NGK IRIDIUM IX Spark Plugs, NGK Wires,
6000K Hid's,5 speed swap, fidanza 8lb flywheel,
Walbro 190lph fuel pump, Vtec front brakes,
Powerstop drilled/slotted rotors,
Powerstop ceramic pads, 70mm OP Throttle body
Vibrant StreetPower Axleback

1993 Impreza
RIP 1990 Nissan 240SX Coupe w/redtop SR20DET
2007 Subaru Forester
1995 Ford Ranger
!990 Integra DA
1951 Ford Hardtop
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Old 01-18-2009, 10:30 PM
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Re: Wierd idle fluctuation issue maybe cause by ECU

I went ahead and got a grounding kit by buddy club. It equalizes all the electrical loads, and minimizes electrical surges. That might help you too. That's weird that your RPMs jump as high as 1100. Mine only jumps about 50-100 max.
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Old 01-19-2009, 02:36 AM
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Re: Wierd idle fluctuation issue maybe cause by ECU

lmao dang mine is idling at around 1200 right now,,,
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Old 01-19-2009, 02:37 AM
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Re: Wierd idle fluctuation issue maybe cause by ECU

..........(idk how to delete this comment)
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Old 01-19-2009, 02:38 AM
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Re: Wierd idle fluctuation issue maybe cause by ECU

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Originally Posted by bdmski View Post
Did you tighten the idle screw like I suggested in the other thread? Mine idled at 1100 too before I tightened it. Now it idles at 750, and I don't have any problems with lights on or whatever.
dang...and at 750 it doesnt feel like it wants to give out??
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Old 01-19-2009, 03:21 AM
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Re: Wierd idle fluctuation issue maybe cause by ECU

Idle at 450-500 it idles so damn quiet.
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Old 01-19-2009, 09:33 AM
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Re: Wierd idle fluctuation issue maybe cause by ECU

750 is what i believe its supposed to idle at.
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Old 01-19-2009, 05:56 PM
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Re: Wierd idle fluctuation issue maybe cause by ECU

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Originally Posted by si96Lude View Post
750 is what i believe its supposed to idle at.
That would be correct + or - 50
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1992 Prelude si 4ws H22A swap
WingsWest Big Mouth Kit,Shaved Handles,
emblems, Stock si wheels atm, Tokico Blues,
Tein lowering springs, MSD Cap
and coil, NGK IRIDIUM IX Spark Plugs, NGK Wires,
6000K Hid's,5 speed swap, fidanza 8lb flywheel,
Walbro 190lph fuel pump, Vtec front brakes,
Powerstop drilled/slotted rotors,
Powerstop ceramic pads, 70mm OP Throttle body
Vibrant StreetPower Axleback

1993 Impreza
RIP 1990 Nissan 240SX Coupe w/redtop SR20DET
2007 Subaru Forester
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Old 01-19-2009, 07:30 PM
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Re: Wierd idle fluctuation issue maybe cause by ECU

try and find a usdm p13 so you wont have the speed cut.
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Old 01-19-2009, 07:49 PM
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Re: Wierd idle fluctuation issue maybe cause by ECU

Quote:
Originally Posted by mizlude View Post
try and find a usdm p13 so you wont have the speed cut.
That is exactly what I am going to do.
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1992 Prelude si 4ws H22A swap
WingsWest Big Mouth Kit,Shaved Handles,
emblems, Stock si wheels atm, Tokico Blues,
Tein lowering springs, MSD Cap
and coil, NGK IRIDIUM IX Spark Plugs, NGK Wires,
6000K Hid's,5 speed swap, fidanza 8lb flywheel,
Walbro 190lph fuel pump, Vtec front brakes,
Powerstop drilled/slotted rotors,
Powerstop ceramic pads, 70mm OP Throttle body
Vibrant StreetPower Axleback

1993 Impreza
RIP 1990 Nissan 240SX Coupe w/redtop SR20DET
2007 Subaru Forester
1995 Ford Ranger
!990 Integra DA
1951 Ford Hardtop
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Old 01-20-2009, 07:12 AM
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Re: Wierd idle fluctuation issue maybe cause by ECU

Quote:
Originally Posted by bdmski View Post
I went ahead and got a grounding kit by buddy club. It equalizes all the electrical loads, and minimizes electrical surges. That might help you too. That's weird that your RPMs jump as high as 1100. Mine only jumps about 50-100 max.
Yea with the P28 it only jumps up about 50-100 like you say. It is also strange to me that I didn't get a CEL with the auto ecu after the 5 speed swap. Everywhere I read said you had to get a manual ecu.
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1992 Prelude si 4ws H22A swap
WingsWest Big Mouth Kit,Shaved Handles,
emblems, Stock si wheels atm, Tokico Blues,
Tein lowering springs, MSD Cap
and coil, NGK IRIDIUM IX Spark Plugs, NGK Wires,
6000K Hid's,5 speed swap, fidanza 8lb flywheel,
Walbro 190lph fuel pump, Vtec front brakes,
Powerstop drilled/slotted rotors,
Powerstop ceramic pads, 70mm OP Throttle body
Vibrant StreetPower Axleback

1993 Impreza
RIP 1990 Nissan 240SX Coupe w/redtop SR20DET
2007 Subaru Forester
1995 Ford Ranger
!990 Integra DA
1951 Ford Hardtop
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