Car broke down and won’t start
Thread Starter
Teching In
Joined: Jun 2021
Posts: 16
Likes: 0
From: Maryland
Car broke down and won’t start I recently did a heads and cam swap on my ls1 camaro. I got it to fire up and even got it to idle although very roughly. After the spring break in I decided to take it down my short street and back to see if it would scrape because I also just lowered the car. I never went above 2300rpm but it was running very rich and poorly. When I went to turn around in a driveway the car sputtered and then stalled out. It now won’t start. It will crank over and it occasionally fires a cylinder or two but will not start even with a lil squirts of break clean to help it. I got a few codes that came up P0135 and P0122. I read a bad 02 sensor will make the car run like crap but it will still run. Could the combination of those 2 codes point me in the right direction or what could cause it to not want to start anymore? If I bought hp tuners and get a flash tune sent to me would that correct this issue? I have a dyno tune appointment Monday and I’m wondering if the tuner would be able to help me out or if he’d just say I’m **** out of luck since it doesn’t start. Any advice would be appreciated thank you.
Probably the worst thing anyone could do to potentially hurt an LS, is try to start their recently modded HCI engine before a tune. Patience is a virtue guys…surely you can hold out til the tuner gets the first flash into the ECM.
Thread Starter
Teching In
Joined: Jun 2021
Posts: 16
Likes: 0
From: Maryland
TECH Fanatic
Joined: Oct 2022
Posts: 1,775
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From: Louisiana
you always tune your car after your make mechanical upgrades, tow your car to a tuner and let him tune it or find a remote tuner and give him a list of all the parts you have installed on the car. I'm no tuner so I can't help you with that but I assure you that you need to get it done.
Thread Starter
Teching In
Joined: Jun 2021
Posts: 16
Likes: 0
From: Maryland
you always tune your car after your make mechanical upgrades, tow your car to a tuner and let him tune it or find a remote tuner and give him a list of all the parts you have installed on the car. I'm no tuner so I can't help you with that but I assure you that you need to get it done.
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Moderator
Joined: Aug 2010
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From: Ann Arbor, MI
By "cam swap" we assume you mean a hotter cam with more duration and overlap.
At lower RPMs this causes the engine is run too rich because the volumetric efficiency (VE) is lower. (With a higher duration cam it is higher at high RPM but lower at low RPM.)
THEN, it causes "unused/unburnt" oxygen to go out the exhaust; the O2 sensors sense this and think the engine is running too lean, causing them to enrichen the mixture even more, until your engine is pig rich, the spark plugs foul, your piston rings are no longer lubricated, and so on.
At lower RPMs this causes the engine is run too rich because the volumetric efficiency (VE) is lower. (With a higher duration cam it is higher at high RPM but lower at low RPM.)
THEN, it causes "unused/unburnt" oxygen to go out the exhaust; the O2 sensors sense this and think the engine is running too lean, causing them to enrichen the mixture even more, until your engine is pig rich, the spark plugs foul, your piston rings are no longer lubricated, and so on.
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12 Second Club
Joined: Apr 2015
Posts: 154
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From: West Coast
In a perfect world it would have a startup base tune.
That’s not always the case.
Put new plugs in, load it on a trailer or drive easy to the tuner.
You’re most likely fine, you couldn’t even guess the amount of LS engines that have had their first startup “untuned”.
It’s not ideal to start it untuned, but it’s also not gonna be the death of your engine.
Get it tuned and report back. I’m sure you’ll be pleased with the new setup 👍
That’s not always the case.
Put new plugs in, load it on a trailer or drive easy to the tuner.
You’re most likely fine, you couldn’t even guess the amount of LS engines that have had their first startup “untuned”.
It’s not ideal to start it untuned, but it’s also not gonna be the death of your engine.
Get it tuned and report back. I’m sure you’ll be pleased with the new setup 👍
I have a tuning appointment scheduled but ya I can definitely see it was dumb to try and drive it even the short distance. But are there any other problems that doing that could have caused besides it flooding? Seeing “yikes, big mistake” definitely scared me I can’t lie lol.
