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replacement injectors '89 350 tpi

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Old May 6, 2014 | 09:16 PM
  #1  
johndinu's Avatar
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From: Montreal, QC, CANADA
Car: '89 GTA 350 hardtop
replacement injectors '89 350 tpi

Hi,
I think I want to replace my multecs (I have at least 2 bad ones) with a set of bosch gen3 24lbs.
I'm wondering once I have the plenum off, what else to replace once I'm there (besides injector o-rings and intake gaskets) fuel pressure regulator, egr?
thanks!
PS: car is almost stock besides a high flow cat and cat-back
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Old May 7, 2014 | 12:41 PM
  #2  
timfitz63's Avatar
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Joined: Aug 2012
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From: Lorena & San Antonio, TX
Car: 1989 Firebird Formula
Engine: 5.0L TPI (LB9)
Transmission: 5-speed Manual
Axle/Gears: 3.45 w/Limited Slip
Re: replacement injectors '89 350 tpi

Just went through this exact process with my '89 5.0L TPI Formula (coincidentally, I had two bad injectors too). I think you've got it mostly covered; in addition to the fuel injectors, I replaced the fuel rail O-rings, fuel regulator diaphragm, EGR valve, all of the related gaskets, and a small, U-shaped coolant hose that is at the front of the throttle body assembly on the plenum. You'll probably want to get yourself one of those hoses and just put on a new one; you'll be removing it anyway during the tear-down process to get to the injectors.

Good luck!
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Old May 7, 2014 | 08:42 PM
  #3  
johndinu's Avatar
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From: Montreal, QC, CANADA
Car: '89 GTA 350 hardtop
Re: replacement injectors '89 350 tpi

my car have a rough idle, almost like wanting to stall. cleaned up the throttle body and idle control valve.
how did your car acted after these refreshments?
PS: If you are referring to the hose which runs coolant thru the throttle body, I have bypassed that long time ago.
thanks
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Old May 8, 2014 | 11:49 AM
  #4  
timfitz63's Avatar
Member
10 Year Member
 
Joined: Aug 2012
Posts: 112
Likes: 3
From: Lorena & San Antonio, TX
Car: 1989 Firebird Formula
Engine: 5.0L TPI (LB9)
Transmission: 5-speed Manual
Axle/Gears: 3.45 w/Limited Slip
Re: replacement injectors '89 350 tpi

Originally Posted by johndinu
my car have a rough idle, almost like wanting to stall. cleaned up the throttle body and idle control valve.
how did your car acted after these refreshments...?
Mine had a rough idle too, but not so much to the point where it seemed like it would stall. But definitely rough. The real symptom of mine was it would want to quit when I put a load on it -- put it in gear to move it or even turn on the A/C compressor... And once the engine got warmed up, it was really bad...

Originally Posted by johndinu
... If you are referring to the hose which runs coolant thru the throttle body, I have bypassed that long time ago.
thanks
That's the one. Not really sure myself what the purpose of that hose is; but if you've got it capped off, I guess it's not all that crucial...
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