Crate LS6 install problems (F-body)
Crate LS6 install problems (F-body) My '98 LS1 died. So I bought a LS6 from GM. My mechanic installed it and hooked up my old FAST intake, stock TB, EGR, and AIR. NOW, after about ten minutes of driving it will idle low/rough and will eventually stall.. He said it's not throwing any codes (besides the lack of cats). I'm running headers and that intake and that's it. Our plan is to put the original LS6 intake back on and remove all emissions gear. Ideas?
Teching In
Joined: Jan 2006
Posts: 13
Likes: 0
From: Chicago
Congrats on getting an LS6 put in, I was planning on doing that myself. It is a very difficult and may even be beyond this forum to try and troubleshoot this without being there. I had a similar problem when I pulled my EGR and Air off and put the block off plates on my 2000 T/A. I forgot to put one of the plates on 
along with a disconnected spark plug wire and I started it, the engine would start but it had a rough idle then stall, but didn't throw any codes. Once I blocked the other EGR hole up and plugged in the spark wire it was good to go.
Check:
-Spark plug wires on all cylinders and coils for connection and continuity
-you never mentioned how big of injectors you had on your fuel rail, you could be flooding the engine or not sufficient fuel from one or all injectors
-hopefully not, but there may be something caught in the intake runner of one of the cylinders. How much of the engine was taken appart? Or it came straight from the factory bad. (possibilty)
-Anything else that was moddified on the crate motor that needs to be double checked that you may not have mentioned
-Did your LS6 come with its own new intake w/injectors? If so, try that like you said.
-idle air control, mass air flow
If all else fails, hopefully by you modifying your engine already, you didn't void your warranty and you could just return it or get it installed by LS engine experienced mechanics that may be in your area.
Take any info on this forum with a grain of salt
along with a disconnected spark plug wire and I started it, the engine would start but it had a rough idle then stall, but didn't throw any codes. Once I blocked the other EGR hole up and plugged in the spark wire it was good to go.Check:
-Spark plug wires on all cylinders and coils for connection and continuity
-you never mentioned how big of injectors you had on your fuel rail, you could be flooding the engine or not sufficient fuel from one or all injectors
-hopefully not, but there may be something caught in the intake runner of one of the cylinders. How much of the engine was taken appart? Or it came straight from the factory bad. (possibilty)
-Anything else that was moddified on the crate motor that needs to be double checked that you may not have mentioned
-Did your LS6 come with its own new intake w/injectors? If so, try that like you said.
-idle air control, mass air flow
If all else fails, hopefully by you modifying your engine already, you didn't void your warranty and you could just return it or get it installed by LS engine experienced mechanics that may be in your area.
Take any info on this forum with a grain of salt
Might have your mech put a scanner on and monitor the sensors... and functions..
TPS, IAT, IAC, O2, etc... if not throwing any code, you may see one of the parms being way out of range. Make sure all of the sensor are within the operating ranges. Check the FSM for trouble shooting and step by step procedures.
Check all of the grounds and connectors to make sure they are tight and seated.
Good luck
TPS, IAT, IAC, O2, etc... if not throwing any code, you may see one of the parms being way out of range. Make sure all of the sensor are within the operating ranges. Check the FSM for trouble shooting and step by step procedures.
Check all of the grounds and connectors to make sure they are tight and seated.
Good luck
well the fast has a suck entry for the map sensor. Did you clamp it tight witha bracket? Make sure none of the wires are crossed.Something is not on right. A ls6 should run fine with no stalling on your stock computer.
Nice upgrade. Do you have the original LS1 tune in the computer or did you get an LS6 tune? That could be the issue considering the LS6 has better heads, bigger cam, plus you put on a bigger intake as well...you should have a tune after all those upgrades.
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11 Second Club
Joined: Jun 2008
Posts: 60
Likes: 1
From: Sayre, PA
I'm pretty sure its the tune, my car did the same thing until I got it flashed with a stock 04 ZO6 tune. Then it may take some minor tweaking from there since you have the FAST intake and TB like me.
i haven't had mine tuned yet and it runs really good. idk why yours would do that. did it start up and run fine or has it done it all along. could be bad plug or wire but that would prolly throw the mis fire code. and i don't think your intake and throttle body would just make it run lean. what octane you run? i would also say MAF but you said it's new. did you hook up the other pvc valve? i know on mine it had another vaccum port on the passenger valve cover
I'm thinking some of the stuff of the older LS1 needs to be tuned out, and the computer tuned in general. Like he said above the LS6 doesn't require the EGR, and you're running the older computer.....lots of possibilities.
My friends car ran rough after installing his ls6 but he put a 228r and larger injectors in his, but it didnt like to idle and was hard starting. On another note ed tuned it for him today and made 415/388 to the wheels.
