high shift points and SES light on.. FIXED :)

Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's, Olds 98 91-96, Buick Lesabres and Park Avenue 91-96. Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.
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mhobryan
SLE Member
SLE Member
Posts: 25
Joined: Sat Sep 08, 2012 8:27 am
Year and Trim: 1995 Bonneville SE

high shift points and SES light on.. FIXED :)

Post by mhobryan »

Replaced the IAC yesterday on my 1995 Bonnie (SE w/ series II). Also cleaned MAF and TPS with electrical cleaner. Think I FINALLY fixed a nagging warm hard start problem. As soon as I started it up the CES light came on. Also noticed that the shift points on the transmission are now a lot higher - even at partial throttle have to let up in order for it to up shift. down shifts are fine.

My theory is that some of the electric cleaning fluid got into the vacuum actuated diaphragm thingy (what is this called?) on the transmission....your folks thoughts? I doubt seriously the IAC would affect shift points on the trans...but... :dontknow:
Last edited by mhobryan on Mon Jan 14, 2013 3:37 pm, edited 1 time in total.
Jrs3800
Retired Admin/Techinfo Admin
Retired Admin/Techinfo Admin
Posts: 26009
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Year and Trim: 03 SLE, 95 SE, 95 TS SE
Location: Space Coast, or at least it used to be

Re: high shift points and SES light on..

Post by Jrs3800 »

Sounds like a bad TPS... The Vac Modulator is only used to control line pressure( shift feel ) not shift timing... shift timing is all done by load factor a.k.a TPS values.. Now you need to know what the PCM is seeing from the TPS..
mhobryan
SLE Member
SLE Member
Posts: 25
Joined: Sat Sep 08, 2012 8:27 am
Year and Trim: 1995 Bonneville SE

Re: high shift points and SES light on.. FIXED :)

Post by mhobryan »

^^^^ You were right. I pulled the TPS out and recleaned it. I suspect I had the little tang in front of the "T" instead of behind it when I first installed after cleaning yesterday. Thanks!
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