Basic Tuning of the LU5 Crossfire?
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Junior Member
Joined: Oct 2014
Posts: 76
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From: Seattle, Washington
Car: 83 Firebird Trans Am
Engine: 305 LU5 Crossfire Injection
Basic Tuning of the LU5 Crossfire?
Hey guys 'n gals,
I've got an '83 Trans Am with CFI I've picked up as a daily... 175K, great oil pressure, just needs valve stem seals which I will address.
I set base timing at 6 BTDC as my engine bay instructed, reconnected the wire, and that has been about it. My high idle works wonders ~1400RPM, but it does take quite a long time to warm up and kick down. Then it wants to idle closer to 900-1000RPM
When it kicks down, and is fully warm, it can do one of two things... Idle a bit low, as if it's not getting enough fuel and actually stall out [very, VERY rarely, usually after a semi-warm start], or idle a bit on the high side and really test my new brakes when I'm cruising less than 15 MPH.
At any rate, I know there's a MAF[??], TPS, and the fuel pressure regulator is inside of the throttle bodies.. Right? Is there any resource for tuning this? Set base idle, timing, checking voltage/impedance of sensors, etc. I'm afraid the previous owner claimed that he tuned it, and I'm not sure how many screws he randomly turned...
It's also had its air pump pulley removed, and the EGR system isn't even hooked up right now... He claims it needs a new EGR, but not sure why smog pump was disabled. I'd like for it to burn clean and get a bit better gas mileage, this is not a race car!
I also hear these crossfires really desire the OEM system in perfect working order, which is about right. My TB's are very clean, and the engine does look to be taken care of.
For any insight, links to tuning [I've searched already] or any books I should pick up, I'd appreciate it. After tuning and examining, I'll be adding my results to my thread for others to access as well.
I have a carb and intake sitting around, but I would MUCH RATHER stick with the CFI injection. It's just too cool. Anything can be modified to run correctly, it just depends on the lengths of which you're willing to travel.
THANK YOU!
For fun, here's a video of it running in a warmer day [50 degrees]
-TunaTrky
I've got an '83 Trans Am with CFI I've picked up as a daily... 175K, great oil pressure, just needs valve stem seals which I will address.
I set base timing at 6 BTDC as my engine bay instructed, reconnected the wire, and that has been about it. My high idle works wonders ~1400RPM, but it does take quite a long time to warm up and kick down. Then it wants to idle closer to 900-1000RPM
When it kicks down, and is fully warm, it can do one of two things... Idle a bit low, as if it's not getting enough fuel and actually stall out [very, VERY rarely, usually after a semi-warm start], or idle a bit on the high side and really test my new brakes when I'm cruising less than 15 MPH.
At any rate, I know there's a MAF[??], TPS, and the fuel pressure regulator is inside of the throttle bodies.. Right? Is there any resource for tuning this? Set base idle, timing, checking voltage/impedance of sensors, etc. I'm afraid the previous owner claimed that he tuned it, and I'm not sure how many screws he randomly turned...
It's also had its air pump pulley removed, and the EGR system isn't even hooked up right now... He claims it needs a new EGR, but not sure why smog pump was disabled. I'd like for it to burn clean and get a bit better gas mileage, this is not a race car!
I also hear these crossfires really desire the OEM system in perfect working order, which is about right. My TB's are very clean, and the engine does look to be taken care of.
For any insight, links to tuning [I've searched already] or any books I should pick up, I'd appreciate it. After tuning and examining, I'll be adding my results to my thread for others to access as well.
I have a carb and intake sitting around, but I would MUCH RATHER stick with the CFI injection. It's just too cool. Anything can be modified to run correctly, it just depends on the lengths of which you're willing to travel.
THANK YOU!
For fun, here's a video of it running in a warmer day [50 degrees]
-TunaTrky
Last edited by tunatrky; Nov 15, 2014 at 01:34 PM. Reason: no iFrame for video
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From: Chasing Electrons
Car: check
Engine: check
Transmission: check
Re: Basic Tuning of the LU5 Crossfire?
No MAF, has a MAP sensor.
Check the TBI board here there are quite a few threads on the x-fire systems.
RBob.
Check the TBI board here there are quite a few threads on the x-fire systems.
RBob.
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