Generation III External Engine LS1 | LS6 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

Surging question from ported TB

Thread Tools
 
Search this Thread
 
Old 09-15-2004, 11:41 AM
  #1  
TECH Apprentice
Thread Starter
iTrader: (2)
 
shaneSS's Avatar
 
Join Date: Mar 2004
Posts: 317
Likes: 0
Received 0 Likes on 0 Posts
Default Surging question from ported TB

GUys,

Before I tore the car down to install teh F13, I have put on a Jantzer ported TB the previous week. After the install, the car started surging and idling very high.

I went back and checked for vacuume leaks and found none. I then took the TPS and IAT sensors off my stocker and swapped them thinking it may be the TPS. NO luck. still surged.

Im not sure what else can be wrong. I mean If i swapped the sensors It must be a vacuume leak that Im not picking up with the traditional gum-cuter test.

let me know what you may have seen in past experiances. Here is exactly what the car does.

start the car cold and it idles fine untill it goes into open loop. then it wants to idle at 1500.

driving along is fine then when I come to a light and depress the clutch the engine revs to 2k and hold for 4 sec, drops to 1500 and holds for 4 sec then dropps to 1k and stays.

THis sounds like a typical vacuume leak and the computer is trying to compensate but like I said, I cant find a leak.

The only code that auto tap pulled was idle higher than expected.

ANy help would be greatly apreciated. As I said the car is apart for the F13 install now so I wil probably have to deal with this again once its back together. I would hate to have to put the non ported one back on after the cam install. But the ideling issue is untolerable.


ANy thought appreciated.

Oh and yes I backed the set screw (throttle adj) all the way off and still idles high.



Thanks.
Old 09-15-2004, 12:35 PM
  #2  
TECH Apprentice
Thread Starter
iTrader: (2)
 
shaneSS's Avatar
 
Join Date: Mar 2004
Posts: 317
Likes: 0
Received 0 Likes on 0 Posts
Default

ANyone. or am I being retarded and just need to get out there and look harder for a vacuum leak. I just wnat to make sure no one has run into this before and Im not overloking something.

Thanks again.
Old 09-15-2004, 12:36 PM
  #3  
Moderator
iTrader: (11)
 
jimmyblue's Avatar
 
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes on 6 Posts

Default

I would inspect the IAC bore and plunger seat for residual
crud from the epoxy fill and powdercoating process. The
IAC that came with the TB may not be good either, can you
swap one from your stocker?
Old 09-15-2004, 01:25 PM
  #4  
TECH Apprentice
Thread Starter
iTrader: (2)
 
shaneSS's Avatar
 
Join Date: Mar 2004
Posts: 317
Likes: 0
Received 0 Likes on 0 Posts
Default

I swapped the IAC from teh stocker w/ no luck. I need to check the bore though. It looked clean at first glance but Ill look again.
Old 09-15-2004, 04:41 PM
  #5  
TECH Senior Member
iTrader: (4)
 
GuitsBoy's Avatar
 
Join Date: Apr 2003
Location: Long Island, NY
Posts: 6,249
Received 3 Likes on 3 Posts

Default

Also, make sure that the plate is sealing tightly against the bore. I had an issue with too much air causing surging. Try temporarily plugging the TB hole with a small screw and nut.

-T
Old 09-15-2004, 06:25 PM
  #6  
10 Second Club
iTrader: (15)
 
White Fire'99's Avatar
 
Join Date: Nov 2001
Location: Phx,Az
Posts: 356
Likes: 0
Received 0 Likes on 0 Posts

Default

check to see if your idle hole is bigger than the stock one....
Old 09-15-2004, 06:34 PM
  #7  
Launching!
 
LT1Burnout's Avatar
 
Join Date: Jul 2004
Location: HighDesert California
Posts: 273
Likes: 0
Received 1 Like on 1 Post
Default

check ur map sensor, could b faulty or clogged
Old 09-15-2004, 06:54 PM
  #8  
TECH Enthusiast
 
Hambone 7's Avatar
 
Join Date: Jan 2004
Location: Chattanoga TN
Posts: 574
Likes: 0
Received 0 Likes on 0 Posts
Default

does you ecu have a custom tune? i'd unplug mine and reset it if you have done some mods to the engine.
Old 09-15-2004, 08:25 PM
  #9  
TECH Apprentice
Thread Starter
iTrader: (2)
 
shaneSS's Avatar
 
Join Date: Mar 2004
Posts: 317
Likes: 0
Received 0 Likes on 0 Posts
Default

check check and check. forgeot to mention initally that I left the batery off over night, no custom tune yet, stock hole in throttle plate and I hope its not the MAP sensor as that wasnt changed. I havent however tried to plug the hole to check if the throttle plate may not be sealing enough when off throtle.

Ill try this friday, Thanks for the tips. Ill let you know what happenes after its back together. I cant wait




All times are GMT -5. The time now is 07:54 PM.