L99 doesn't start after refueling
Thread Starter
Teching In
Joined: Mar 2023
Posts: 45
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From: USA, Maine
L99 doesn't start after refueling Could anybody advise, any suggestions are very appreciated. 2011 camaro ss L99
2 times after refueling (1 time full tank, second time half a tank), car won't start after getting gas, Starter quits spinning the engine and engine starts 1 time of 10 attempts. When it starts, I have check engine light with fault code P0336 and with 'service stabilitrack' message along with ABS, Traction, ESP lights are come on. In this case I feel rough idle and shacking (as if 2 cylinders are off). No misfire codes in ECU.
Or... I can wait 10-15 mins and start car normally without any issues.
Could bad crackshaft sensor / and / or starter be a reason of this issue ? If yes, why after getting gas ?
P.S. On hot engine I sometimes have slow crank but engine always starts. On every engine run I see 'Service Stabilitrak' msg, even on cold engine in winter.
2 times after refueling (1 time full tank, second time half a tank), car won't start after getting gas, Starter quits spinning the engine and engine starts 1 time of 10 attempts. When it starts, I have check engine light with fault code P0336 and with 'service stabilitrack' message along with ABS, Traction, ESP lights are come on. In this case I feel rough idle and shacking (as if 2 cylinders are off). No misfire codes in ECU.
Or... I can wait 10-15 mins and start car normally without any issues.
Could bad crackshaft sensor / and / or starter be a reason of this issue ? If yes, why after getting gas ?
P.S. On hot engine I sometimes have slow crank but engine always starts. On every engine run I see 'Service Stabilitrak' msg, even on cold engine in winter.
Last edited by PlymouthBarracuda; Apr 3, 2023 at 04:40 AM.
If it only does it after filling the tank I'd start looking at EVAP(if its still hooked up). If a solenoid is stuck open, when you are filling up, it can push fuel into the engine which floods it out.
Thread Starter
Teching In
Joined: Mar 2023
Posts: 45
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From: USA, Maine
Thread Starter
Teching In
Joined: Mar 2023
Posts: 45
Likes: 1
From: USA, Maine
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Thread Starter
Teching In
Joined: Mar 2023
Posts: 45
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From: USA, Maine
Car starts great when cold. The hotter it gets, the slower the starter spins. Once I already changed the starter for this reason. Could you please advice what wheel this valve is located behind?
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Thread Starter
Teching In
Joined: Mar 2023
Posts: 45
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From: USA, Maine
How can I check this purge valve ? I don't have ECU error codes for it.
I remember on my past 2012 camaro RS 3.6 it made noise after starting the engine..
Staging Lane
Joined: Apr 2023
Posts: 84
Likes: 13
From: Ohio
The EVAP Purge valve is connected between intake manifold vacuum and the EVAP charcoal canister.
The computer decides when to pulse it open at a given percentage of the time it is commanded on. If it is electrically functional, you can touch it and feel this happening as the engine runs when the valve is being powered. Some are loud and can be heard as a rapid clicking type of noise.
This allows fuel vapor to be sucked out of the canister and into the intake and then burned as fuel.
They commonly get stuck open on some vehicles.
Common codes could be "flow during non-purge", P0300, EVAP leak of any variety can set if it is stuck open while the monitor is run, it can cause rich codes initially, lean codes if ignored and run for a long time. It is very possible to not have a code - or have a seemingly unrelated code - at least initially.
The most common symptom is a hard start after refueling, and then the car running rough for a short period.
The easiest way to check this is as follows:
- Locate your purge valve
- Disconnect electrical connector
- Disconnect the line/hose/tube coming from the tank. Leave the other side hooked up to the intake manifold.
- Start engine
- Place your finger over the opening you have created on the back of the purge valve
- If you feel vacuum, your purge valve is stuck open. Sometimes it can be only partially open and you would need to hold your finger there for 20 seconds or so, but usually it is obvious.
Thread Starter
Teching In
Joined: Mar 2023
Posts: 45
Likes: 1
From: USA, Maine
Hopefully you have resolved this, but I will explain.
The EVAP Purge valve is connected between intake manifold vacuum and the EVAP charcoal canister.
The computer decides when to pulse it open at a given percentage of the time it is commanded on. If it is electrically functional, you can touch it and feel this happening as the engine runs when the valve is being powered. Some are loud and can be heard as a rapid clicking type of noise.
This allows fuel vapor to be sucked out of the canister and into the intake and then burned as fuel.
They commonly get stuck open on some vehicles.
Common codes could be "flow during non-purge", P0300, EVAP leak of any variety can set if it is stuck open while the monitor is run, it can cause rich codes initially, lean codes if ignored and run for a long time. It is very possible to not have a code - or have a seemingly unrelated code - at least initially.
The most common symptom is a hard start after refueling, and then the car running rough for a short period.
The easiest way to check this is as follows:
The EVAP Purge valve is connected between intake manifold vacuum and the EVAP charcoal canister.
The computer decides when to pulse it open at a given percentage of the time it is commanded on. If it is electrically functional, you can touch it and feel this happening as the engine runs when the valve is being powered. Some are loud and can be heard as a rapid clicking type of noise.
This allows fuel vapor to be sucked out of the canister and into the intake and then burned as fuel.
They commonly get stuck open on some vehicles.
Common codes could be "flow during non-purge", P0300, EVAP leak of any variety can set if it is stuck open while the monitor is run, it can cause rich codes initially, lean codes if ignored and run for a long time. It is very possible to not have a code - or have a seemingly unrelated code - at least initially.
The most common symptom is a hard start after refueling, and then the car running rough for a short period.
The easiest way to check this is as follows:
- Locate your purge valve
- Disconnect electrical connector
- Disconnect the line/hose/tube coming from the tank. Leave the other side hooked up to the intake manifold.
- Start engine
- Place your finger over the opening you have created on the back of the purge valve
- If you feel vacuum, your purge valve is stuck open. Sometimes it can be only partially open and you would need to hold your finger there for 20 seconds or so, but usually it is obvious.
Does this test also check the Vapor Canister Vent Valve / Solenoid ? In any case I bought both, purge valve and vent valve, plus a fuel pump with a new starter...
As you already noticed, "hard start after refueling, and then the car running rough for a short period". In my case this period is pretty long, about 20 mins. I can start engine hard with applying some throttle, but now transmission falls into the backup mode (not shift from 3 to 4), check engine light comes on with Crankshaft Position Sensor fault. Starter just rejects to crank in my case, looks like that some signal disconnect it from battery. First it start to slooooooowly rotate then stops. I tried refuel without engine shutdown and had no problems at all
Staging Lane
Joined: Apr 2023
Posts: 84
Likes: 13
From: Ohio
Thank you very much for such a detailed answer!
No problem!
Does this test also check the Vapor Canister Vent Valve / Solenoid ? In any case I bought both, purge valve and vent valve, plus a fuel pump with a new starter...
This does not test the vent valve, but the only likely symptom of a faulty vent valve (other than codes and MIL) is difficulty refueling. As in, the pump keeps shutting off before the tank is full. This would be in the case of a stuck closed vent valve or clogged filter if it has one. Stuck open just results in fuel vapor exiting to the atmosphere and a vent/EVAP leak code with a light.
I wouldn't go replacing all of those parts right away. You could end up building in more problems by replacing parts that aren't the issue. NEW stands for "Never Ever Worked before", you know.
As you already noticed, "hard start after refueling, and then the car running rough for a short period". In my case this period is pretty long, about 20 mins. I can start engine hard with applying some throttle, but now transmission falls into the backup mode (not shift from 3 to 4), check engine light comes on with Crankshaft Position Sensor fault. Starter just rejects to crank in my case, looks like that some signal disconnect it from battery. First it start to slooooooowly rotate then stops. I tried refuel without engine shutdown and had no problems at all
I would attempt to keep the car running for a minute or two when this happens, using the throttle. If it clears up, it's possible that it's all related. Does the car start and then stall initially? This in itself can cause erroneous codes like CKP codes if the computer expects the engine to be running and it stops.
On the other hand, the slow cranking leads me to believe this might be a coincidence as far as happening when refueling. Any other slow cranking incidents? I would definitely check your battery terminals. Don't check with a wrench, but try to rotate the cables by hand and see if you are able to move the terminal on the post easily.
Do you have a voltmeter to check battery voltage and charging system? Or a built in one?
If these checks don't yield any results, you may need to get a scan tool hooked up that can read codes in your other modules after this happens.
No problem!
Does this test also check the Vapor Canister Vent Valve / Solenoid ? In any case I bought both, purge valve and vent valve, plus a fuel pump with a new starter...
This does not test the vent valve, but the only likely symptom of a faulty vent valve (other than codes and MIL) is difficulty refueling. As in, the pump keeps shutting off before the tank is full. This would be in the case of a stuck closed vent valve or clogged filter if it has one. Stuck open just results in fuel vapor exiting to the atmosphere and a vent/EVAP leak code with a light.
I wouldn't go replacing all of those parts right away. You could end up building in more problems by replacing parts that aren't the issue. NEW stands for "Never Ever Worked before", you know.
As you already noticed, "hard start after refueling, and then the car running rough for a short period". In my case this period is pretty long, about 20 mins. I can start engine hard with applying some throttle, but now transmission falls into the backup mode (not shift from 3 to 4), check engine light comes on with Crankshaft Position Sensor fault. Starter just rejects to crank in my case, looks like that some signal disconnect it from battery. First it start to slooooooowly rotate then stops. I tried refuel without engine shutdown and had no problems at all
I would attempt to keep the car running for a minute or two when this happens, using the throttle. If it clears up, it's possible that it's all related. Does the car start and then stall initially? This in itself can cause erroneous codes like CKP codes if the computer expects the engine to be running and it stops.
On the other hand, the slow cranking leads me to believe this might be a coincidence as far as happening when refueling. Any other slow cranking incidents? I would definitely check your battery terminals. Don't check with a wrench, but try to rotate the cables by hand and see if you are able to move the terminal on the post easily.
Do you have a voltmeter to check battery voltage and charging system? Or a built in one?
If these checks don't yield any results, you may need to get a scan tool hooked up that can read codes in your other modules after this happens.
Thread Starter
Teching In
Joined: Mar 2023
Posts: 45
Likes: 1
From: USA, Maine
thanks a lot..
Does the car start and then stall initially? No, it makes 2-3-4 extremely slow turns and stall. Immediately after that, the second attempt to start the engine and get out of a gas station usually is "good", car starts with extremely rough idle, like a truck diesel engine, feeling shaking, loss of power, nervous, you know... Can't drive in this mode . After that when I moved away from gas station, all attempts to crank make just 1 -1.5 slow turn and starter stops. I can start it with some throttle applied and get in this case check engine light with Crankshaft position sensor fault, Service Stabilitrak with all 3 lights (abs, Traction). With these active faults transmission rejects to shift more than 3.
Any other slow cranking incidents? Yes, every time when the engine is hot enough, especially after long driving in downtown in hard traffic. I replaced starter motor to the low price one (wai global) 1 year ago. That time new starter corrected this issue. But I never had a troubles after getting gas.
What is the connections between the battery, starter and refueling? It's 14V on charging and 12V in normal. I remove battery for recharging every 3-4 moths. Negative terminal is tight enough but sometimes I have a water near battery and in the inner side of the cover that lies on top .
Could you please advise if relearn procedure is required when crankshaft position sensor is replaced ? Is GM 12703627 good enough ? I tried Delphi SS11397 yesterday, but the car refused to start, now OK with original old one. I believe that ls3 and l99 have the same sensors
Does the car start and then stall initially? No, it makes 2-3-4 extremely slow turns and stall. Immediately after that, the second attempt to start the engine and get out of a gas station usually is "good", car starts with extremely rough idle, like a truck diesel engine, feeling shaking, loss of power, nervous, you know... Can't drive in this mode
. After that when I moved away from gas station, all attempts to crank make just 1 -1.5 slow turn and starter stops. I can start it with some throttle applied and get in this case check engine light with Crankshaft position sensor fault, Service Stabilitrak with all 3 lights (abs, Traction). With these active faults transmission rejects to shift more than 3.Any other slow cranking incidents? Yes, every time when the engine is hot enough, especially after long driving in downtown in hard traffic. I replaced starter motor to the low price one (wai global) 1 year ago. That time new starter corrected this issue. But I never had a troubles after getting gas.
What is the connections between the battery, starter and refueling? It's 14V on charging and 12V in normal. I remove battery for recharging every 3-4 moths. Negative terminal is tight enough but sometimes I have a water near battery and in the inner side of the cover that lies on top .
Could you please advise if relearn procedure is required when crankshaft position sensor is replaced ? Is GM 12703627 good enough ? I tried Delphi SS11397 yesterday, but the car refused to start, now OK with original old one. I believe that ls3 and l99 have the same sensors
Last edited by PlymouthBarracuda; Apr 27, 2023 at 12:26 AM.