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I recently built my first LS for my 1998 Camaro SS, but I'm having major issues getting the motor to idle. I've tried many tune adjustments to get it to work, but I haven't had any luck. The car will crank and start perfectly fine, then die 1-2 seconds later. There are a few things I've noticed happening:
-IAC circuit is almost maxed out at ~175 steps compared to a desirable 40-60 step
-As timing ramps in from 0deg to 18deg, RPM drops and eventualy the motor dies
-Me operating the throttle will not keep the motor alive; opening the throttle drops RPM. When the throttle closes, RPM increases slightly
-Sometimes RPM seems uncontrollable and will shoot up to 3000RPM, then dies
I'm thinking this is an issue with the size of the idle air circuit(Too small for the engine), causing the IAC to be open +170 steps. I can adjust where the throttle blade stops, but the adjustments seem to make no positive change. Would anyone be able to point me in the correct direction?
I've included a image of my datalog, datalog file, and tune file. I've copied the LS2 injector data onto this tune as best I can.
The build is as follows:
~10.0 Compression Ratio BTR Stage 2 V1 NA Camshaft AFR 230cc CNC ported heads
LS2 Intake
LS2 Injectors
103mm Chinese throttle body
Long tube headers
AEM WB02 30-0300 tied into the EGR circuit
Hp Tuners MPVI4
Other sensors or things I didn't mention are stock(MAP sensor, MAF sensor, etc)
I'll admit to being wrong a lot, so it could be the case here. I think I see why a vacuum leak was suggested. Looking at my recent LS1 HCI Logs, I see similar trends with Map and IAC values, keep in mind there's only a few seconds of log here. The biggest thing I see in the tune is you have larger than stock injectors (by a little bit) and a cam, but the VE looks completely stock. My suggestion, disable VE (Airflow -> Dynamic -> High RPM Disable = 0) and see if it'll run with just the MAF. I just wonder if it's flooding out and dying from too much fuel. I attached a recent log from my setup with fast 36 lb injectors and a 102/102 setup that starts and runs every time.
I was able to get to run once, setting High RPM disable to 0. Thank you!
The issue now is it's running lean, or I think it is. Also, the throttle response is extremely odd: once you tap the throttle, it rises uncontrollably after I've let off the pedal. I have an AEM wideband hooked into the EGR circuit, and the gauge goes full lean during idle. I tested the sensor with the butane and a starting fluid-soaked rag, and it worked fine. I also did a quick vacuum leak check and came up with nothing major. I messed with the VE table, and it doesn't seem to have an effect.
I was able to get to run once, setting High RPM disable to 0. Thank you!
The issue now is it's running lean, or I think it is. Also, the throttle response is extremely odd: once you tap the throttle, it rises uncontrollably after I've let off the pedal. I have an AEM wideband hooked into the EGR circuit, and the gauge goes full lean during idle. I tested the sensor with the butane and a starting fluid-soaked rag, and it worked fine. I also did a quick vacuum leak check and came up with nothing major. I messed with the VE table, and it doesn't seem to have an effect.
I spent 5 weeks with similar issues, chasing odd readouts etc
my problem was getting the main engine harness to connect to the ecu correctly. I ended up connecting to ecu and hitting the plug with the back of a hammer to get it to seat properly
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LS1 Starts then Dies 
