idle setting and the est wire?

[Volkspanzer]

I have read on this forum about setting base idle and have used that procedure. Today I was searching around the net and found almost the exact same procedure except disconnecting the est wire was included along with unplugging the IAC.The reason being was the computer will try to adjust timing to compensate for the idle change. So which is it?? Unplug EST or not?

 

[speedmaster4]

i've been told that unplugging the est was not part of the 85 service manual but came in for 86 & up (sorry i don't have an 85 manual)....86 up the ecm responds to tps position/maf input/distributor rpm and advances spark (just like your grandpa's vacuum advance)---you can unplug/plug your 85 est and watch with a timing light to see if 85 does this (let us know if you try it)...with the spark advanced, idle speed increases and idle speed screw setting will not be correct,causing tps to be adjusted improperly.
if its not in the 85 manual, it may not be necessary, or maybe they goofed and it does need to be disconnected..85 ecm is much different from 86+ ecm...guess you get to re-engineer this one
i'm not much help on this one,just trying to add a little background that might help you, sorry

 

[Volkspanzer]

Anyone else????

 

[tigmaned]

go by what your emission sticker says. the sticker on my 86 is on the driverside of the rad.
when i checked mine with the timeing light with the est wired plugged in i didn't even see the mark on the balancer, but when i un-plugged it i did. 86 is seta 6 tdc.

 

[vetteboy86]

The only advice I can offer is to try it. You may get the results you are after, or you may not. Either way hopefully you will learn and have a better outcome then when you started. I cannot see it hurting things.

Craig

 

[Agent 86]

My 86 manual does not mention the EST wire in the base idle/TPS adjustment