replaced TPS and now idle at 2000 rmp - Third Generation F-Body Message Boards

Go Back  Third Generation F-Body Message Boards > Tech Boards > Carburetors
Reload this Page >

replaced TPS and now idle at 2000 rmp

Carburetors Carb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.

replaced TPS and now idle at 2000 rmp

Old 10-17-2018, 09:09 PM
  #1  
Junior Member
Thread Starter
 
galwahh's Avatar
 
Join Date: Jun 2018
Location: Ohio
Posts: 23
Car: 1986 Berlinetta
Engine: 305
Transmission: automatic
replaced TPS and now idle at 2000 rmp

Hello - 86 305 - anything come to mind as a reason for a high idle after replacing my TPS? it started fine after i put it back together. There is a cam on the choke that appears to need some know-how for reassembly - any feedback would be great!
galwahh is offline  
Old 10-18-2018, 02:51 PM
  #2  
Supreme Member
iTrader: (11)
 
norcalz28's Avatar
 
Join Date: Jul 2003
Location: Brentwood, CA
Posts: 1,998
Car: 1989 Camaro IROC-Z
Engine: ZZZ# 0607 of 1200 produced
Transmission: Pro-Built 700R4/Vig.2400
Axle/Gears: 3.27 BW 9 Bolt PBR Disc
Re: replaced TPS and now idle at 2000 rmp

Check your alternator. I had a bad one on my LG4 that affected the choke. Would idle high and get stuck there.
norcalz28 is offline  
Old 10-19-2018, 08:10 AM
  #3  
Junior Member
Thread Starter
 
galwahh's Avatar
 
Join Date: Jun 2018
Location: Ohio
Posts: 23
Car: 1986 Berlinetta
Engine: 305
Transmission: automatic
Re: replaced TPS and now idle at 2000 rmp

thanks for the reply, interesting thought, but i'm pretty sure my alternator is good. Is there some setting on the choke plate rod when you put the air horn back together or something along that line? Would a screwed up choke even be able to cause an idle of over 2k rmp?
galwahh is offline  
Old 10-19-2018, 10:09 AM
  #4  
Supreme Member
iTrader: (11)
 
norcalz28's Avatar
 
Join Date: Jul 2003
Location: Brentwood, CA
Posts: 1,998
Car: 1989 Camaro IROC-Z
Engine: ZZZ# 0607 of 1200 produced
Transmission: Pro-Built 700R4/Vig.2400
Axle/Gears: 3.27 BW 9 Bolt PBR Disc
Re: replaced TPS and now idle at 2000 rmp

Its electric. Sensitive to changes in voltage. Look at the wiring diagram for the choke or carb. A bad diode in the alternator could cause this. I had to block my choke linkage with a spare Pcv valve until I could replace the alternator. It fit right down in there
norcalz28 is offline  
Old 10-20-2018, 06:35 PM
  #5  
Junior Member
Thread Starter
 
galwahh's Avatar
 
Join Date: Jun 2018
Location: Ohio
Posts: 23
Car: 1986 Berlinetta
Engine: 305
Transmission: automatic
Re: replaced TPS and now idle at 2000 rmp

i unplugged the TPS and it did idle down to about 1500 so it must need adjusted - which requires drilling out the cap on the adjustment screw - seems like a million things could go wrong - any tips on that procedure would be great..

Last edited by galwahh; 10-20-2018 at 08:36 PM.
galwahh is offline  
Old 10-23-2018, 07:29 PM
  #6  
Junior Member
Thread Starter
 
galwahh's Avatar
 
Join Date: Jun 2018
Location: Ohio
Posts: 23
Car: 1986 Berlinetta
Engine: 305
Transmission: automatic
Re: replaced TPS and now idle at 2000 rmp

So the TPS did not need adjusted after all, the issue was with the fast idle cam. I cleaned some gunk off of it which I think helped, but i'm not sure if it's 100% working correctly or not. It seems to drop one step but i had to manually push it down the second step to get the idle all the way down to about 700 rmp. Is the fast idle cam supposed to drop on it's own or is it released by stepping on the throttle?
galwahh is offline  
Old 10-24-2018, 08:02 AM
  #7  
Supreme Member
iTrader: (1)
 
Join Date: Sep 2005
Posts: 21,055
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: replaced TPS and now idle at 2000 rmp

When the choke stat heats up enough, it will literally pull the choke off, when you step on the throttle. A much more positive action than merely "release".

Did you get the link that works the choke blade hooked back up properly inside the passage that goes down the side of the carb?
sofakingdom is offline  
Old 10-27-2018, 12:45 PM
  #8  
Junior Member
Thread Starter
 
galwahh's Avatar
 
Join Date: Jun 2018
Location: Ohio
Posts: 23
Car: 1986 Berlinetta
Engine: 305
Transmission: automatic
Re: replaced TPS and now idle at 2000 rmp

Hi sofakingdom - thanks for chiming in. It seems to be working perfectly now, - starts up 1000 rpm, revs up to about 1200 after a couple minutes, and then idles down to about 650 with a quick tap on the throttle. I think it was just the high idle mechanism got gummed up from working on it just enough to cause the it to stick...it doesn't take much...and best of all the check engine light is not coming on now so the TPS was bad and this whole exercise was not a waste of time!

For my next question check out the electrical forum
galwahh is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
TransAm_85
Tech / General Engine
13
02-22-2009 06:06 PM
camaro05
TPI
7
01-02-2006 04:53 PM
TransAm86
Power Adders
6
05-02-2003 04:35 PM


Thread Tools
Search this Thread
Quick Reply: replaced TPS and now idle at 2000 rmp


Advertising
Featured Sponsors
Vendor Directory

Contact Us Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: