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

90. fc with idle problem (video)

Thread Tools
 
Search this Thread
 
Old Feb 26, 2012 | 04:05 PM
  #1  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
MD 90. fc with idle problem (video)

https://www.youtube.com/watch?v=IPVH...e_gdata_player





it does the hole cold start. but as soon it finishes, it bounces. i pulled the plug from the throttle body. & it smooths out at cold start revs. 3500 rpms
Reply
Old Feb 26, 2012 | 04:46 PM
  #2  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
bump. edit video
Reply
Old Feb 26, 2012 | 06:08 PM
  #3  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
anybody ?? help
Reply
Old Feb 26, 2012 | 06:15 PM
  #4  
Logicalbomb's Avatar
I wanna go fast.
iTrader: (1)
 
Joined: Sep 2010
Posts: 142
Likes: 1
From: Coeur D' Alene Idaho
Alright the first thing to check is for ANY air leaks from the throttle body to the filter box. The second thing I would check is your two adjustment points on top of the upper manifold. There should be a screw directly on top of the throttle body that allows you to adjust the throttle intake. Try adjusting that lower to see if it decreases that throttle bobble.
Reply
Old Feb 26, 2012 | 06:57 PM
  #5  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
thanks any other suggestions?
Reply
Old Feb 26, 2012 | 07:37 PM
  #6  
Logicalbomb's Avatar
I wanna go fast.
iTrader: (1)
 
Joined: Sep 2010
Posts: 142
Likes: 1
From: Coeur D' Alene Idaho
TPS sensor perhaps, they go out constantly.
Reply
Old Feb 26, 2012 | 08:48 PM
  #7  
SpikeDerailed's Avatar
This sh*t burns oil!
Tenured Member: 15 Years
iTrader: (7)
 
Joined: Oct 2006
Posts: 1,239
Likes: 5
From: Charlotte, NC - USA
That thing is idling WAY to highfor being fully warmed up. First find the vacuum leak you have and fix that, then when you get it to idle at 750 fully warm set the narrow range tps to 1volt at the ecu.
Reply
Old Feb 27, 2012 | 02:02 AM
  #8  
-RotorDemon-'s Avatar
Rotary nut for 15 years.
 
Joined: Dec 2011
Posts: 118
Likes: 2
From: Gresham, OR
Check the codes and see what you find. TPS will do that, So will the IAT.
Reply
Old Feb 27, 2012 | 03:39 AM
  #9  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
thanks guys. more info the better!
Reply
Old Feb 27, 2012 | 06:53 AM
  #10  
Molotovman's Avatar
Ban Peak
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (50)
 
Joined: Jul 2002
Posts: 4,248
Likes: 550
From: Northern Virginia
Best way to check for vac leaks: Start it up and spray carb cleaner around the manifold mating surfaces and vacuum hoses. If it's sucking in unmetered air, the engine will suck in the carb cleaner at the location of the leak and speed up.

It could also be a stuck throttle plate, and is your timing correct? Did the car sit for a long time beofre you got it?
Reply
Old Feb 27, 2012 | 06:57 AM
  #11  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
yes. it sat for awhile. the second ports are stuck also.
Reply
Old Feb 27, 2012 | 06:58 AM
  #12  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
ill get a better video clip when i get off work.
Reply
Old Feb 27, 2012 | 09:46 AM
  #13  
spahn1's Avatar
240sx guru
 
Joined: May 2011
Posts: 108
Likes: 0
From: Jasper Alabama
not sure if this helps but i had a honda that did that, it was the mapping sensor
Reply
Old Feb 27, 2012 | 01:30 PM
  #14  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
https://www.youtube.com/watch?v=37dA...e_gdata_player


updated video!
Reply
Old Feb 27, 2012 | 01:39 PM
  #15  
spahn1's Avatar
240sx guru
 
Joined: May 2011
Posts: 108
Likes: 0
From: Jasper Alabama
holy **** dude........
Reply
Old Feb 27, 2012 | 01:53 PM
  #16  
Molotovman's Avatar
Ban Peak
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (50)
 
Joined: Jul 2002
Posts: 4,248
Likes: 550
From: Northern Virginia
Have you checked for vac leaks? Have you flushed the coolant?

From the video it just seems like the thermowax in your TB isn't functioning right. My car hunts like that until it's warmed up all the way.

Your throttle plates could be stuck too.

You physically need to make an attempt to work on it, taking the suggestions we've made, and tell us the results.

You keep on asking "What's wrong" and have never made a post reflecting that you've tested our suggestions. Sorry but we can't help you unless you make an attempt.
Reply
Old Feb 28, 2012 | 02:43 PM
  #17  
SpikeDerailed's Avatar
This sh*t burns oil!
Tenured Member: 15 Years
iTrader: (7)
 
Joined: Oct 2006
Posts: 1,239
Likes: 5
From: Charlotte, NC - USA
That plug you pulled is the throttle position sensor. If the car doesnt see the tps signal it ignores it and uses the maf, map, cas, and h20 temp for timing and fueling needs. The car SHOULD NOT be idling at over 2000rpms. You have a air leak somewhere, be it metered(thermowax failed open, bavc open, aws open, throttle cable binding) or an unmetered vacuum leak...and a large one at that. Ignore the 6pi and vdi right now, even of those are stuck it wont cause the problem you currently have.
Reply
Old Feb 28, 2012 | 03:04 PM
  #18  
boosted414's Avatar
547hp at the flywheel
Tenured Member 10 Years
iTrader: (30)
 
Joined: Oct 2008
Posts: 1,223
Likes: 0
From: Chicago
its definitely a vac leak combined with the TPS being most likely bad or out of adjustment
Reply
Old Feb 28, 2012 | 04:51 PM
  #19  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
where's the "tps" located?
Reply
Old Feb 28, 2012 | 05:55 PM
  #20  
boosted414's Avatar
547hp at the flywheel
Tenured Member 10 Years
iTrader: (30)
 
Joined: Oct 2008
Posts: 1,223
Likes: 0
From: Chicago
its the 2 black plungers on the side of the throttle body connected to that plug you are disconnected.

http://atkinsrotary.com/store/images...91T-TPS-01.jpg
Reply
Old Feb 28, 2012 | 08:13 PM
  #21  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
i tryed the curb cleaner with ever hose & seal i saw. nothing happend,still did the bounceing. coolant looks soo nasty & smells bad. gotta change it. the tps is bad, i believe because when i push down on the throttle, the rpms drop alot. but still bounce. im taking it to dave at speed1 for a rebuild/streetport anyways.
Reply
Old Feb 28, 2012 | 11:27 PM
  #22  
esjoson1126's Avatar
TyrannosaurusRX7
Tenured Member 10 Years
 
Joined: Jan 2007
Posts: 110
Likes: 0
From: Southern California
check UIM, LIM for vacuum leak, check TPS, check BAC, extra ground etc. good luck!
Reply
Old Mar 1, 2012 | 08:29 PM
  #23  
87FCna's Avatar
Thread Starter
Stoned
Tenured Member 15 Years
iTrader: (3)
 
Joined: Apr 2007
Posts: 500
Likes: 2
From: Arbutus ,Maryland
when i do replace my tps. how do i reset my idle?
Reply
Old Mar 5, 2012 | 07:44 AM
  #24  
rotoman2's Avatar
Full Member
Tenured Member: 15 Years
 
Joined: Feb 2006
Posts: 145
Likes: 0
From: Michigan/ Florida
bad aws

My 91 NA did exactly the same thing all of a sudden. The accelerated warm up valve (aws on the driver's side of the UIM) was Stuck open or something. I just plugged up the hose and everything was fine.
Reply
Old Mar 7, 2012 | 02:19 PM
  #25  
SystemIDx's Avatar
My **** keeps breaking.
Tenured Member 10 Years
iTrader: (2)
 
Joined: Jul 2005
Posts: 86
Likes: 0
From: Columbia, Maryland
Edit: Nevermind someone already posted my solution.
Reply



All times are GMT -5. The time now is 07:45 PM.