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Fast idle at startup


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1988 Deville

Today for first time, when I started the engine it raced very fast. The idle speed did not want to decrease even when I blipped the accelerator. Finally, it settled down, but the "Service Soon" light came on, went off, came on, went off. Every time I started the car, the engine idled fast initially, even when warm, but after a couple starts the "Service Soon" light did not come on. Through this site, I found the engine diagnostic code procedure. Retrieved the code E26. Does a particular part need replacement or could it be many different things? Would this be an easy repair or a dealer only repair?

Thanks for anyone's help.

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  • 3 weeks later...

Thanks to ba-ba-bbobynski and all those who responded to my problem. The new ISC motor is in and problem appears solved.

One point I would like to make for anyone else doing this repair. Repair procedures call for you to apply 12v to the motor terminals to fully extend or fully retract it the actuator. There are a total of 4 terminals on the ISC motor, two for the motor and 2 for the internal switch. You must know which are which because you have to avoid putting any voltage on the switch terminals. Some repair manuals such as Haynes refer to the motor terminals as C and D, but provide ambiguous illustrations of which terminals are C and D. Logically, you might think that terminals C and D are the bottom two as the motor is installed. The illustration in the Haynes manual reinforces that impression. However, the motor terminals are actually the top two. This is better illustrated in the Chilton's manual, which shows an upside down view of the ISC motor so c and D are the bottom two terminals. But who needs a manual, the terminal identification is engraved on the bracket that supports the motor, although it is very hard to see unless you know it is there. So forget the manuals and look at the bracket. What a surprise. :rolleyes:

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