Help with start up tune
#1
Staging Lane
Thread Starter
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I have HP tuners but I have no clue what I'm doing yet. I have a Hummer that had a custom tune with the stock LQ4.
I have now built a LQ9 with 243 heads, a BTR stage II low lift cam and a TBSS intake with flex fuel injectors.
All I know about the last tune was that the tuner threw a bunch of fuel and timing at it. I am afraid to start this thing to take it to my local tuner. Am I being paranoid? I have looked at several email tune sites and they all want my current tune but I don't think it is safe with this engine. The compression should be 11 to 1 ish compared to stock 9.4 to 1 and I have no clue what the injector change will require.
Can anyone steer me in the right direction to get it started safely? I am willing to learn but don't know where to begin.
Tim
I have now built a LQ9 with 243 heads, a BTR stage II low lift cam and a TBSS intake with flex fuel injectors.
All I know about the last tune was that the tuner threw a bunch of fuel and timing at it. I am afraid to start this thing to take it to my local tuner. Am I being paranoid? I have looked at several email tune sites and they all want my current tune but I don't think it is safe with this engine. The compression should be 11 to 1 ish compared to stock 9.4 to 1 and I have no clue what the injector change will require.
Can anyone steer me in the right direction to get it started safely? I am willing to learn but don't know where to begin.
Tim
#2
TECH Enthusiast
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Do you have a wideband installed and configured to read in HP Tuners? If the "Flex Fuel" injectors are the popular gen4 36lb or the 50lb injectors (new to the LQ9 not installed in the previous LQ4 tune) the data needs to be converted to work with the gen3 LQ9. I have a similar build LQ9 TBSS and the gen4 (12613412) 50 lb/hr injectors. The converted data is in the injector sticky here on the forum. What are the part numbers for your injectors.
If you have a wideband to read air fuel and the correct injector data... I see no reason not to fire the engine and log some data in HP tuners. Then members here can see what is going on with the tune.
If you have a wideband to read air fuel and the correct injector data... I see no reason not to fire the engine and log some data in HP tuners. Then members here can see what is going on with the tune.
#4
TECH Enthusiast
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Guy with a Chevy (08-05-2023)
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timharber (03-21-2021)
#7
11 Second Club
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[QUOTE=timharber;20337737]I have HP tuners but I have no clue what I'm doing yet. I have a Hummer that had a custom tune with the stock LQ4.
I have now built a LQ9 with 243 heads, a BTR stage II low lift cam and a TBSS intake with flex fuel injectors. I am afraid to start this thing to take it to my local tuner. Am I being paranoid?
Your tuner should be able to provide you with a startup tune but they will need a read of the current file on the ECM with your HPtuner software. Just send them that hpt file and all the details on your build and they should be able to send you back the hpt file so you can then write it to the vehicle for start up.
I have now built a LQ9 with 243 heads, a BTR stage II low lift cam and a TBSS intake with flex fuel injectors. I am afraid to start this thing to take it to my local tuner. Am I being paranoid?
Your tuner should be able to provide you with a startup tune but they will need a read of the current file on the ECM with your HPtuner software. Just send them that hpt file and all the details on your build and they should be able to send you back the hpt file so you can then write it to the vehicle for start up.
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#8
Staging Lane
Thread Starter
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Initial start tune. Needs some work but sound good. I could not have gotten this far without my good buddy Chris Pedone from Brevard Discount transmission. He did the tuning to get it to this point. I have some things to button up before he tunes it some more. Thanks for all the help from this board! This thing is going to be fun
New LQ9 shortblock, 243 heads, BTR Stage II truck cam, NNBS intake with flex fuel injectors and GM 92mm throttle body. Built 4l65E with TBSS I6 converter.
Tim
New LQ9 shortblock, 243 heads, BTR Stage II truck cam, NNBS intake with flex fuel injectors and GM 92mm throttle body. Built 4l65E with TBSS I6 converter.
Tim