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SPARK CHASER

By SPARK CHASER
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SPARK CHASER Enthusiast

SPARK CHASER

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I removed the distributor on my old reliable 1993 Silverado 5.7L to replace the pickup coil. Reinstalled distributor after new coil,cap,rotor, and ignition module installed. It went back in with no problems-all marks lined right back up. Fired up the truck. It fired up beautifully. Idle air control was working fine. I let the truck warm up to temperature. I then shut the truck off to disconnect the Tan and Black wire to bypass the spark control to set timing at 0 degrees. Upon restart I checked and set the timing. Shut the truck off again to reconnect the wire. I then disconnected the battery to reset the SES. Reconnected the battery and attempted to restart and the truck will barely idle and the IAC will not step up the idle when the A/C is engaged. Truck does not run right and I know it's because the IAC is not working. Is there some special procedure I missed? I'm not getting an SES light either. This problem has me baffled. I hope I didn't fry something by accident.

RCH Enthusiast

RCH

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You may need to double check your timing, I had a 1991 Sierra when reading up on the EST, the manual stated that the EST will correct up to 15 degrees. If you didn't mess with the IAC that shouldn't be the issue. Hope this helps.

SPARK CHASER Enthusiast

SPARK CHASER

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You may need to double check your timing, I had a 1991 Sierra when reading up on the EST, the manual stated that the EST will correct up to 15 degrees. If you didn't mess with the IAC that shouldn't be the issue. Hope this helps.

 

Thanks for the reply. I removed the IAC valve and shoved the pintle all the way back in and then reinstalled the IAC. Truck fired right up and now everything is working correctly. I guess this IAC valve just got stuck in the fully closed position. I forgot to mention this is a Holley TBI unit. The IAC is slightly different. The "outer shell" is made of plastic, instead of metal, but the pintle design is the same as the Rochester.

RCH Enthusiast

RCH

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Glad you solved it, I had an issue with the 1991 Sierra I used to own, nothing major it just bothered me. Things like this can be frustrating, but it feels great when you solve it. LOL.

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