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95 Eldorado high idle problems


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I have a 95 Eldorado with an idle issue, here is what it does. After start up, the idle will gently bounce between 1 and 2k rpms, and will only drop when the brake is applied. Once the brake is on, it idles where is should at about 700 rpms. If I take the brake off, it will creep back up to bouncing between 1 and 2. When the car is driving and gas is not applied the car will maintain speed, as the idle does not drop down, but once the brake is tapped or applied, the idle will drop down to where it needs to be. Its like of like an all time cruise control. Here are the codes that pop up. From what I have read this is some kind of Idle air control valve or Idle speed control actuator. Please let me know if you can help.

Powertrain Control Module (PCM) Codes (Engine/Transmission)

Engine Control Module (ECM) Codes*

P027(E027) ...... Open throttle signal switch

P036 (E036) ..... EGR Valve Pintle Position Out of Range

P039 (E039) ..... Torque Coverter Clutch/Viscous Converter Clutch Engagement Problem

P095 (E095) ..... Engine Stall Detected

P110 (E110) ..... Generator L-terminal Circuit Problem

No IPC

No ACP

Supplemental Inflatable Restraint (SIR) Codes

R017 .................................. Passenger Initiator Circuit Open

R026 .................................. Driver Initiator Circuit Open

R035 .................................. Discriminating Sensor Open or Missing

No TCS

No RSS

PCM?

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I've had three Northstar powered Sevilles over the last 4 years, and they have all had the same problem. An erratic idle that eventually turns into a steady high idle around 2000-2500 rpm. In all 3 cases, the idle speed actuator has been the culprit. Your P027 code tells you there's probably a problem with the switch inside the actuator. The actuator is a black device, about 3"x2"x2", with a plunger sticking out of it that pushes on the throttle linkage at the throttle body. If you're skilled in repairing small devices, sometimes the actuator can be dissasembled, cleaned and lubed, and it'll be fine again, otherwise you'll need a new one, about $125 to $150. It's only held on by 3 little nuts, but one of them is a bugger to get to. Also, the nuts are stainless, so if you drop one into a tight spot, you can't fish it out with a magnet. (yes, I dropped one down under the water pump housing)

Jeff

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I have a 95 Eldorado with an idle issue, here is what it does. After start up, the idle will gently bounce between 1 and 2k rpms, and will only drop when the brake is applied. Once the brake is on, it idles where is should at about 700 rpms. If I take the brake off, it will creep back up to bouncing between 1 and 2. When the car is driving and gas is not applied the car will maintain speed, as the idle does not drop down, but once the brake is tapped or applied, the idle will drop down to where it needs to be. Its like of like an all time cruise control. Here are the codes that pop up. From what I have read this is some kind of Idle air control valve or Idle speed control actuator. Please let me know if you can help.

Powertrain Control Module (PCM) Codes (Engine/Transmission)

Engine Control Module (ECM) Codes*

P027(E027) ...... Open throttle signal switch

P036 (E036) ..... EGR Valve Pintle Position Out of Range

P039 (E039) ..... Torque Coverter Clutch/Viscous Converter Clutch Engagement Problem

P095 (E095) ..... Engine Stall Detected

P110 (E110) ..... Generator L-terminal Circuit Problem

No IPC

No ACP

Supplemental Inflatable Restraint (SIR) Codes

R017 .................................. Passenger Initiator Circuit Open

R026 .................................. Driver Initiator Circuit Open

R035 .................................. Discriminating Sensor Open or Missing

No TCS

No RSS

PCM?

Hi, I'm having the same exact problem with my 95 sts....did you get the problem solved?

Thanks

Scott

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  • 1 month later...

Well, the acutuator or idle speed control seemed to do the trick. It worked right away and then I had some more idle issues, sometimes at 900 or 500. It has been working well all this week, idling at 600 - 700, so I'm hoping it continues to idle correctly. Thanks for all the help.

Does this device need to be set, or is it just plug in and go?

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  • 1 year later...

The ISC motor needs to be adjusted. Press on the plunger and it should retract. When it bottoms out, unplug it. Now set the gap to .060, plug it back in and you are good to go.

I'm having a similar problem relearning the ISC. It idels fine since I replaced the ISC motor. Howeverf, when I turn the ignition off the ISC motor starts thumping the throttle for about 20 seconds. It's loud and cannot be good for the ISC. Is it possible that I have the plunger set too far in. Do you think backing out the plunger might stop this?

Craig

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That seems to be somewhat common. I was once told that that meant it was failing, but I'm starting to doubt that, especially since yours was just replaced.

Actually I think I may have been wrong on the gap. Try setting it to .030. If that corrects it, please accept my apology and report back and let me know.

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  • 9 months later...

The reason the ISC motor is clicking after a turn off is the PCM is trying to relearn the throttle position and idle values. If you have a factory service manual, there is a procedure to get this to stop. It is the throttle position idle relearn override on your pcm.

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