2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Problem with idle in my S5 turbo

Thread Tools
 
Search this Thread
 
Old Sep 13, 2004 | 03:54 AM
  #1  
Noodlebut's Avatar
Thread Starter
Junior Member
Tenured Member 20 Years
 
Joined: Apr 2003
Posts: 19
Likes: 0
From: Sydney
Problem with idle in my S5 turbo

Hi, recently my car had been running very bad at idle... the gauge was reading approx 200rpm at idle and car sounded like as if it was about to stall sometimes... so i decided to take off the dynamic chamber + TB and clean them out. i done that yesterday.

today when i started it it was all good, but on my way to work i noticed that the idle stayed at about 1300rpm, this is after i set the idle through the BAC valve to about 800rpm. When i noticed that it stayed high, at the lights i pulled up the handbrake and let the clutch out abit so as to let the revs drop but not stall... then i put it back in and found that the idle dropped and stayed at 800rpm.
and it just keeps repeating... after driving it stays at 1300rpm... and sometimes it will go back down to 800rpm...

could this be the TPS sensors? .. i checked their resistance and they seemed to be ok. according to the manual...

although it may not be related, something i just noticed was when at a stop i was reving it to 5000rpm+ and then let it drop to idle, it sounded rough for about 5 sec then went back to normal. there was something like "pops" coming out the exhaust but after a few seconds went back to a nice purr and a "pop" every now and then

cheers.
Reply
Old Sep 13, 2004 | 06:37 AM
  #2  
SureShot's Avatar
Seduced by the DARK SIDE
Tenured Member 15 Years
 
Joined: Apr 2001
Posts: 7,323
Likes: 2
From: Orange Park FL (near Jax)
Some possible causes:

Dirty/sticking BAC.
BAC connector problem.
Throttle linkage/shafts sticking near idle - not always closing completely.
A crack/leak in the TID.
Reply
Old Sep 13, 2004 | 09:13 AM
  #3  
Turbonut's Avatar
Eats, Sleeps, Dreams Rotary
iTrader: (1)
 
Joined: Feb 2002
Posts: 3,993
Likes: 68
From: NJ
Originally Posted by SureShot
Some possible causes:

Dirty/sticking BAC.
BAC connector problem.
Check the BAC inner seal for leakage. Remove BAC and either blow through the air inlet tube, or spray some WD40 into the tube to see if inner seal is operating properly. If air or lube goes past the seal get a new BAC.
Also on the TPS make certain it's set properly after warmup. Set 1K ohm then set via Mazda checker. You'll find that 1K ohm only a good starting point, but in my experience I've found it needs to be fine tuned using the Mazda checker. Too many problems leaving the setting at 1k Ohms.
Reply
Old Sep 13, 2004 | 09:20 AM
  #4  
powrdby13B's Avatar
i'll blow YOUR valve off
Tenured Member 05 Years
 
Joined: May 2004
Posts: 1,064
Likes: 0
From: KC MF MO
BAC? Cold start system? I'd do the TB mod and see what happens.
And did you port your intake when you took it off?
How's your AFM doing? Do you have a stock filter?
Reply
Old Sep 13, 2004 | 01:32 PM
  #5  
Cybaster's Avatar
I think I'm addicted
 
Joined: Feb 2004
Posts: 749
Likes: 2
From: Castro Valley
Originally Posted by Noodlebut
Hi, recently my car had been running very bad at idle... the gauge was reading approx 200rpm at idle and car sounded like as if it was about to stall sometimes... so i decided to take off the dynamic chamber + TB and clean them out. i done that yesterday.

today when i started it it was all good, but on my way to work i noticed that the idle stayed at about 1300rpm, this is after i set the idle through the BAC valve to about 800rpm. When i noticed that it stayed high, at the lights i pulled up the handbrake and let the clutch out abit so as to let the revs drop but not stall... then i put it back in and found that the idle dropped and stayed at 800rpm.
and it just keeps repeating... after driving it stays at 1300rpm... and sometimes it will go back down to 800rpm...

could this be the TPS sensors? .. i checked their resistance and they seemed to be ok. according to the manual...
EXACTLY what my car is doing..... i check the tension of the throttle cable.....
didn't check by BAC yet, but this is EXACTLY what my car is doing.......
someone help us...
Reply
Old Sep 13, 2004 | 01:35 PM
  #6  
SonicRaT's Avatar
Super Raterhater
Tenured Member: 20 Years
iTrader: (6)
 
Joined: Dec 2001
Posts: 10,630
Likes: 3
From: NY, MA, MI, OR, TX, and now LA or AZ!
Usually caused by a BAC that seals completely sometimes, and then others doesn't seal completely. Take it off and clean it thouroghly (I just soaked mine in a parts cleaner bucket overnight), and it fixed my problems right up.
Reply
Old Sep 13, 2004 | 09:31 PM
  #7  
Versatile's Avatar
Full Member
Tenured Member 05 Years
 
Joined: May 2004
Posts: 86
Likes: 0
From: West Valley
Sorta a newb. How do you adjust the BAC?
I replaced my whole engine harness and put everything back together, now when I start my car, my engine idles very rough and died when I drove it around the block once. Sometimes it doesnt even start. What could be my problem? When I first started it, it didnt cold start and idled at about 750, but pretty rough, the whole car vibrated. Can somebody help?
Reply
Old Sep 14, 2004 | 01:49 AM
  #8  
Versatile's Avatar
Full Member
Tenured Member 05 Years
 
Joined: May 2004
Posts: 86
Likes: 0
From: West Valley
bump
Reply
Old Sep 14, 2004 | 02:29 AM
  #9  
Noodlebut's Avatar
Thread Starter
Junior Member
Tenured Member 20 Years
 
Joined: Apr 2003
Posts: 19
Likes: 0
From: Sydney
is there a gasket or seal i need to buy from mazda to replace it if i take off the BAC?

also how can i get one of those checkers? you mean the checker lamp right? can i buy it from mazda?
Reply
Old Sep 14, 2004 | 12:41 PM
  #10  
Cybaster's Avatar
I think I'm addicted
 
Joined: Feb 2004
Posts: 749
Likes: 2
From: Castro Valley
http://www.teamfc3s.org/info/article...odes/main.html

man... that was a long search.... =P next time do your own =D

https://www.rx7club.com/showthread.p...ght=BAC+gasket

people use Black or Blue RTV gasket maker
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
Jul 1, 2023 04:40 PM
Kyo
2nd Generation Specific (1986-1992)
6
Apr 13, 2019 09:24 AM
alphawolff
1st Generation Specific (1979-1985)
17
Nov 17, 2015 05:57 PM
rkhanso
2nd Generation Specific (1986-1992)
1
Aug 13, 2015 11:40 AM




All times are GMT -5. The time now is 05:48 AM.