3.1L fuel injectors
3.1L fuel injectors
I have a 1990 firebird 3.1L. My injectors are original with over 110k miles on them. I have a strong fuel smell from the exhaust and running rich. My fuel regulator is running good and I've gone over everything else and injectors seem to be the last possible issue. I want to replace them. Ive reviewed several other posts from over 15yrs ago about injectors and what works best for the 3.1L but those companies or injectors are no longer available. Does anyone have any ideas on what would be a good replacement?
Joined: Dec 2004
Posts: 16,694
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: 3.1L fuel injectors
Here you go. These injectors are made by bosch. Have 4 hole spray
https://www.southbayfuelinjectors.co...-1992-tpi.html
https://www.southbayfuelinjectors.co...-1992-tpi.html
Re: 3.1L fuel injectors
Here you go. These injectors are made by bosch. Have 4 hole spray
https://www.southbayfuelinjectors.co...-1992-tpi.html
https://www.southbayfuelinjectors.co...-1992-tpi.html
Does anyone have any experience with the Southbay injectors. If so, how are they.
Re: 3.1L fuel injectors
Awesome, thank you. I see that there are also 17lb "upgraded" injectors for the 3.1L but only has Camaro 3.1L listed for fitment on the description but not Firebird 3.1L (like the 15lb injectors do). Isn't it the same 3.1L for both cars in the 1985-1992 models years? If so, would the 17lb injectors work on the Firebird 3.1L? Also, what would be the benefit of the 17lb injectors over the 15lb for a stock 3.1L?
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Re: 3.1L fuel injectors
Update. I purchased the 15lb injectors from Southbay and installed them the same day I received them. After speaking to Frank at Southbay, these injectors install just like the factory ones using the clips on the fuel rail. It was simply plug and play. I didn't have any leaks. Once I started the engine, I could tell it already seemed to be running smoother. Once I drove it around, I could also tell the acceleration had vastly improved and the throttle response was awesome. Great purchase!
Junior Member

Joined: May 2019
Posts: 39
Likes: 5
From: berlin
Car: camaro 91 z28
Engine: 305
Transmission: AT
Re: 3.1L fuel injectors
Update. I purchased the 15lb injectors from Southbay and installed them the same day I received them. After speaking to Frank at Southbay, these injectors install just like the factory ones using the clips on the fuel rail. It was simply plug and play. I didn't have any leaks. Once I started the engine, I could tell it already seemed to be running smoother. Once I drove it around, I could also tell the acceleration had vastly improved and the throttle response was awesome. Great purchase!
Junior Member
Joined: Sep 2025
Posts: 2
Likes: 0
From: Central Maryland
Car: 1991 Camaro RS
Engine: 3.1 V6
Re: 3.1L fuel injectors
Here you go. These injectors are made by bosch. Have 4 hole spray
https://www.southbayfuelinjectors.co...-1992-tpi.html
https://www.southbayfuelinjectors.co...-1992-tpi.html
I was reading the Chilton manual and it indicated for the 3.1L that a scan tool needed to be used to relearn the IAC after it's been disconnected. Has anyone done this?
Last edited by FyrLt01; Mar 19, 2026 at 05:38 PM.
Re: 3.1L fuel injectors
I did the following two procedures back to back and they worked.
FIRST:
Cleaned throttle body with B-12 throttle body cleaner. Carbon melted off the throttle body. That stuff really works much better than CRC and the other brands I've used over the years. Put everything back together and connected IAC and TPS. I would get new throttle body gaskets before you start this. Clean IAC also unless you buy a new one.
PROCEDURE 1:
Disconnected battery for 15mins to drain any residual power and reset ECM codes. Reconnected battery. Turn on ignition but DO NOT start engine. After 1min disconnect IAC plug from throttle body. Turn off ignition with IAC still disconnected at throttle body. Once ignition is off, reconnect IAC plug. DO NOT touch steering wheel or throttle at any point throughout the procedure. If you do, you have to start over from disconnected battery.
PROCEDURE 2:
Disconnect battery, wait one minute, and reconnect.
Turn off A/C.
Turn off Backlight Heater (rear window defroster).
Do Not Touch The Throttle at Any Point.
Do Not Touch The Steering Wheel at Any Point.
Set parking brake and chuck tires.
Start engine, let settle a bit (about 3-5mins) and put trans in drive (while parking brake on and tires chucked).
Let engine run until fan cycles on then off TWO times. This will take about 20-25mins to accomplish.
Turn off engine.
Wait five minutes.
Start engine and place in gear just like before.
Let idle for five minutes.
Shut off engine.
End of procedure.
The following is very important to remember......
If the throttle is touched at anytime during this you have to start from the 'disconnect battery' again.
If the steering wheel has pressure applied you have to start from the 'disconnect battery' again.
If the engine stalls at any point just restart and placeback into gear.
Last edited by 1990FirebirdV6; Mar 19, 2026 at 07:03 PM.
Junior Member
Joined: Sep 2025
Posts: 2
Likes: 0
From: Central Maryland
Car: 1991 Camaro RS
Engine: 3.1 V6
Re: 3.1L fuel injectors
You do not need the scan tool. I was having problems with my IAC for a couple of weeks and tried almost everything and nothing worked until I did the below. My car runs so much better now as a result of the injectors and cleaning and relearn.
I did the following two procedures back to back and they worked.
FIRST:
Cleaned throttle body with B-12 throttle body cleaner. Carbon melted off the throttle body. That stuff really works much better than CRC and the other brands I've used over the years. Put everything back together and connected IAC and TPS. I would get new throttle body gaskets before you start this. Clean IAC also unless you buy a new one.
PROCEDURE 1:
Disconnected battery for 15mins to drain any residual power and reset ECM codes. Reconnected battery. Turn on ignition but DO NOT start engine. After 1min disconnect IAC plug from throttle body. Turn off ignition with IAC still disconnected at throttle body. Once ignition is off, reconnect IAC plug. DO NOT touch steering wheel or throttle at any point throughout the procedure. If you do, you have to start over from disconnected battery.
PROCEDURE 2:
Disconnect battery, wait one minute, and reconnect.
Turn off A/C.
Turn off Backlight Heater (rear window defroster).
Do Not Touch The Throttle at Any Point.
Do Not Touch The Steering Wheel at Any Point.
Set parking brake and chuck tires.
Start engine, let settle a bit (about 3-5mins) and put trans in drive (while parking brake on and tires chucked).
Let engine run until fan cycles on then off TWO times. This will take about 20-25mins to accomplish.
Turn off engine.
Wait five minutes.
Start engine and place in gear just like before.
Let idle for five minutes.
Shut off engine.
End of procedure.
The following is very important to remember......
If the throttle is touched at anytime during this you have to start from the 'disconnect battery' again.
If the steering wheel has pressure applied you have to start from the 'disconnect battery' again.
If the engine stalls at any point just restart and placeback into gear.
I did the following two procedures back to back and they worked.
FIRST:
Cleaned throttle body with B-12 throttle body cleaner. Carbon melted off the throttle body. That stuff really works much better than CRC and the other brands I've used over the years. Put everything back together and connected IAC and TPS. I would get new throttle body gaskets before you start this. Clean IAC also unless you buy a new one.
PROCEDURE 1:
Disconnected battery for 15mins to drain any residual power and reset ECM codes. Reconnected battery. Turn on ignition but DO NOT start engine. After 1min disconnect IAC plug from throttle body. Turn off ignition with IAC still disconnected at throttle body. Once ignition is off, reconnect IAC plug. DO NOT touch steering wheel or throttle at any point throughout the procedure. If you do, you have to start over from disconnected battery.
PROCEDURE 2:
Disconnect battery, wait one minute, and reconnect.
Turn off A/C.
Turn off Backlight Heater (rear window defroster).
Do Not Touch The Throttle at Any Point.
Do Not Touch The Steering Wheel at Any Point.
Set parking brake and chuck tires.
Start engine, let settle a bit (about 3-5mins) and put trans in drive (while parking brake on and tires chucked).
Let engine run until fan cycles on then off TWO times. This will take about 20-25mins to accomplish.
Turn off engine.
Wait five minutes.
Start engine and place in gear just like before.
Let idle for five minutes.
Shut off engine.
End of procedure.
The following is very important to remember......
If the throttle is touched at anytime during this you have to start from the 'disconnect battery' again.
If the steering wheel has pressure applied you have to start from the 'disconnect battery' again.
If the engine stalls at any point just restart and placeback into gear.
I’ll give this a go after I put the new injectors in.
Re: 3.1L fuel injectors
Thanks,
Re: 3.1L fuel injectors
Hey sorry for the late reply. These injectors are hard to come by these days. We were able to get a couple of sets. If you still need them please give us a call in the shop tomorrow?
ask for Frank
516-442-4707
ask for Frank
516-442-4707
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