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

Bad missing under boost

Thread Tools
 
Search this Thread
 
Old 03-05-05, 12:23 PM
  #1  
Senior Member

Thread Starter
 
Spoolerr's Avatar
 
Join Date: Jan 2005
Location: Oakville
Posts: 360
Likes: 0
Received 1 Like on 1 Post
Bad missing under boost

I have an 87 TII, no mufflers but stock exhaust. I find under boost it misses and surges pretty badly, just like its blowing out spark however the plugs are pretty new, wires are new. I am running stock boost with 94 octane, everything else stock.

I am not really sure where to go as i have done a full tune-up and the problem still occurs.

If anyone could help i would appreciate it

thanks
brandon
Old 03-05-05, 02:29 PM
  #2  
Sharp Claws

iTrader: (30)
 
RotaryEvolution's Avatar
 
Join Date: Oct 2003
Location: Central Florida
Posts: 5,107
Likes: 0
Received 41 Likes on 40 Posts
make sure you do not have any vacuum leaks in the system and that the intake hose to the throttle body is tight and do not have any cracks/tears in it as well as the IC hoses.

if that does not help or nothing is found then clean your negative battery terminal end and post and be sure it is nice and snug. remove and clean your negative ground wire where it bolts to the starter and clean the spot where it bolts to the starter. try this and see if it helps, if not then you may have to clean the ECU grounding wire on the top of the rear rotor housing.

if none of those help then you may be having fuel pressure/flow problems, dirty injectors or a semi plugged up fuel filter can cause this as well.

Last edited by RotaryEvolution; 03-05-05 at 02:31 PM.
Old 03-05-05, 02:46 PM
  #3  
Old Fart Young at Heart

iTrader: (6)
 
trochoid's Avatar
 
Join Date: Apr 2004
Location: St Joe MO
Posts: 15,145
Likes: 0
Received 7 Likes on 7 Posts
Start your car up in the dark, pop the hood and bring your rpms up. Look for 'leaking' spark, starting with the coils, working down to the plugs. Friend of mine had the same problem above 5k rpms, he had a crack in the coil tower where the spark plug wire boot connected.
Old 03-05-05, 11:54 PM
  #4  
I'm a boost creep...

 
NZConvertible's Avatar
 
Join Date: Jan 2002
Location: Auckland, New Zealand
Posts: 15,608
Likes: 0
Received 8 Likes on 8 Posts
Same here. I cured a full-load miss by replacing one spark plug wire.
Old 03-06-05, 12:26 AM
  #5  
PIMP

 
therotaryrocket's Avatar
 
Join Date: Feb 2004
Location: Greensboro, NC
Posts: 1,012
Likes: 0
Received 0 Likes on 0 Posts
maybe your wastegate is malfunctioning, and hitting boost-fuel cut. what is the reading on the boost gauge? what kind of plugs do you have? best be ngk. i tried autolites in my old 12a and they had a slight misfire under high load, i used the plugs for less than 60 miles only to get the car running.
Old 03-06-05, 01:04 AM
  #6  
Full Member

 
5252's Avatar
 
Join Date: Feb 2005
Location: Sweet Home Alabama!!!
Posts: 137
Likes: 0
Received 0 Likes on 0 Posts
If your wires and plugs are good, it sounds like it could be the crank angle sensor. Check that, if you have a friend with a turbo II just pull his, swap them real quick and see if it works then.

Last edited by 5252; 03-06-05 at 01:09 AM.
Old 03-06-05, 08:38 AM
  #7  
Senior Member

Thread Starter
 
Spoolerr's Avatar
 
Join Date: Jan 2005
Location: Oakville
Posts: 360
Likes: 0
Received 1 Like on 1 Post
I found it... I changed the vacume line from the im to boost sensor and neglected to re-install the little restrictor in the new line... i just used a bleeder valve and its all cool now

It Has developed a very severe case of the 3800 rpm hesitation tho, so i gotta check that out

thanks
brandon
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
cristoDathird
Introduce yourself
28
05-30-19 08:47 PM
Queppa
New Member RX-7 Technical
8
09-02-18 09:53 AM
CaptainKRM
2nd Generation Specific (1986-1992)
15
08-29-15 01:33 PM
befarrer
Microtech
3
08-22-15 05:52 PM
Wolf_
Single Turbo RX-7's
3
08-11-15 04:23 PM



Quick Reply: Bad missing under boost



All times are GMT -5. The time now is 07:09 AM.