LT1 wont idle
Thread Starter
Staging Lane
Joined: Aug 2014
Posts: 97
Likes: 0
LT1 wont idle Just did a heads and cam swap on my 97 firebird. Went with LE1 heads and a 224/230 cam with supporting mods and tune by Solomon@LT1pcmtuning. Did a break in on sunday and when I took my foot off the gas the car just died. Tried to start twice today with fresh oil in it and it just doesnt want to idle.
I am running open headers until I can drive to the exhaust shop. Did the break in with the O2's plugged in, messaged Solomon about my idle issue and he said to unplug the O2's and reset pcm. Did that today and took a video on second start up.
Am I missing anything? Using Pacesetter mids with egr hook ups and the egr pipe might not be sealed 100% but i planned on blocking it off fully after I smogged. Car threw 2 codes today on first start up before dying. P0336 crank sensor(Which ive read the opti detects the cam and timing and this sensor only helps detect misfires and cant be the reason?) and P0500 vehicle speed sensor. Wrote codes down and then cleared using scanner. Thanks guys
I am running open headers until I can drive to the exhaust shop. Did the break in with the O2's plugged in, messaged Solomon about my idle issue and he said to unplug the O2's and reset pcm. Did that today and took a video on second start up.
Am I missing anything? Using Pacesetter mids with egr hook ups and the egr pipe might not be sealed 100% but i planned on blocking it off fully after I smogged. Car threw 2 codes today on first start up before dying. P0336 crank sensor(Which ive read the opti detects the cam and timing and this sensor only helps detect misfires and cant be the reason?) and P0500 vehicle speed sensor. Wrote codes down and then cleared using scanner. Thanks guys
Thread Starter
Staging Lane
Joined: Aug 2014
Posts: 97
Likes: 0
Stock TB. Oil pump sensor seems to be working. Ive been adjusting the IAC screw a bit more and I think I almost got it but rpms were dipping to around 600 and then jumping back up to 1000. So idk either vacuum leak somewhere maybe or still need to fix IAC and TPS. Also seems like im leaking a little bit of oil from the crank hub so I guess ill need to pull that either this weekend or figure out the idle issue and then replace hub seal.
TECH Resident
Joined: Jun 2013
Posts: 853
Likes: 32
From: Kernersville, NC
Double and triple check all your sensor and component connections. Make sure you didn't leave something unplugged.
You may need to data log it and post up the log so we can look at what it's doing.
You may need to data log it and post up the log so we can look at what it's doing.
Thread Starter
Staging Lane
Joined: Aug 2014
Posts: 97
Likes: 0
Only thing unplugged are my o2 sensors because im running open headers. I still cant get the motor to idle on me. Been adjusting the IAC but doesnt seem to work. If i give the motor throttle it stays alive but when I take my foot off it slowly dies
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
without the 02 sensors being hooked up you are in open loop....don't f around with the TB screw until you get the exhaust/02's on
adjusting the TB screw (read don't do it) will change the TPS volts. More a problem with A4 vs T56 cars
what are your IAC readings at idle??
adjusting the TB screw (read don't do it) will change the TPS volts. More a problem with A4 vs T56 cars
what are your IAC readings at idle??
Thread Starter
Staging Lane
Joined: Aug 2014
Posts: 97
Likes: 0
no clue on exact IAC since my scanner doesnt read that. I tried to follow the guide from Golen engines. Just opening the screw very slightly
http://www.golenengineservice.com/do.../Adj%20TPS.pdf
Can you recomend a good scanner to use that will show IAC. Reason I didnt get one is cause i heard most scanners wont read IAC on an lt1.
Does the video sound like something is wrong mechanically? Its getting harder for me to really diagnose this since I dont have too much experience
http://www.golenengineservice.com/do.../Adj%20TPS.pdf
Can you recomend a good scanner to use that will show IAC. Reason I didnt get one is cause i heard most scanners wont read IAC on an lt1.
Does the video sound like something is wrong mechanically? Its getting harder for me to really diagnose this since I dont have too much experience
Trending Topics
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
IDK what scanners read IAC. Mine doesn't. I have AutoTap which does. It's PC software & cable. POS but I have had it for years. Can't change anything with it, just monitor stuff
yeah I am familiar with the Golen TB thing. That is for larger, aftermarket, TB's. I personally don't subscribe to that method. I did the TB "drill" mod but had the car hooked up to my Auto Tap when doing that. Your TB is stock but for H/C builds it may need the small IAC hole between blades opened 1/64th"...but DO NOT drill anything until you are hooked up to something that can read IAC counts. They want to be 32 at idle (30-35) with engine at operating temp and in closed loop
The fact you don't have your 02's hooked up yet keeps the PCM in open loop mode so not ideal to be tweaking TB while it is still in open loop
nothing I can hear in video from this side of the keyboard that is a problem other than it shuts off quick in 1st video.
yeah I am familiar with the Golen TB thing. That is for larger, aftermarket, TB's. I personally don't subscribe to that method. I did the TB "drill" mod but had the car hooked up to my Auto Tap when doing that. Your TB is stock but for H/C builds it may need the small IAC hole between blades opened 1/64th"...but DO NOT drill anything until you are hooked up to something that can read IAC counts. They want to be 32 at idle (30-35) with engine at operating temp and in closed loop
The fact you don't have your 02's hooked up yet keeps the PCM in open loop mode so not ideal to be tweaking TB while it is still in open loop
nothing I can hear in video from this side of the keyboard that is a problem other than it shuts off quick in 1st video.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo Thread Starter
Staging Lane
Joined: Aug 2014
Posts: 97
Likes: 0
I really appreciate the input. After messing with the IAC and TPS a bit more its more like the first video where it will idle for a few seconds and then die off. Im gonna replace one last hose on the intake just the give me a piece of mind. Other then that tho I might have to send it to a professional. Im hoping its maybe just the IAC and TPS but who knows at this point.
Thread Starter
Staging Lane
Joined: Aug 2014
Posts: 97
Likes: 0
If my TPS was bad would it be causing my symptoms? I get no reading off the blue wire but the other 2 read just fine. Sadly autozone doesnt carry a spare so ill have to special order to find out. Really hoping that this is my fix
Edit: seems maybe the wiring is bad? used the multimeter on the grey and black outlets and they measured only .18 and .01. Seems low. Got the car to idle again and not die, put it in gear and tried to go and it died on me and threw a p0200, checked injector plugs to make sure right one and found one that popped right off. Battery's dead again tho so gonna charge it and try again later
Edit: seems maybe the wiring is bad? used the multimeter on the grey and black outlets and they measured only .18 and .01. Seems low. Got the car to idle again and not die, put it in gear and tried to go and it died on me and threw a p0200, checked injector plugs to make sure right one and found one that popped right off. Battery's dead again tho so gonna charge it and try again later
Last edited by LT1Bird97; Nov 23, 2016 at 04:50 PM.