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2003 Deville
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62 Posts
Discussion Starter · #1 ·
My 2003 Deville as developed an odd starting problem: it only seems to happen after I have gassed up the car, and the greater the fraction of the tank that I fill the more pronounced the problem. The car cranks, catches, and immediately dies. Last time I had to let the car sit 5 or 10 minutes and then it started normally -- all other starts, cold or hot, seem to work flawlessly and the car runs flawlessly except for this one hiccup.

I hypothesized that the gas is colder than the fuel/air mixture above the gas in the tank and that some valve is failing after I seal the gas cap so when the vapor cools and contracts it pulls a partial vacuum and this prevents enough fuel from reaching the motor until the pressure equilibrates somehow. I don't recall it happening on very cold days.

My mechanic is skeptical, but can't figure it out. What has changed recently is that I was getting a code to do with the fuel tank and emissions which I was just clearing -- and like a dummy I didn't record it -- and recently if stopped. Secondly, I recently replaced the gas cap with an OEM gas cap in the bag mainly to replace the lanyard. These changes may have been in the last three or four months and the problem did not begin sharply, but it could have begun around then.

I can't rule out a behavioral problem -- maybe after I fill up the tank there is something subtly different about the way I depress the gas pedal as I turn the key.

What are your thoughts?
 

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2011 CTS4 Coupe, 2014 ELR, 2018 XT5 AWD
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721 Posts
It could be a cannister purge valve problem.
During refueling the cannister gets fuel in it that is then sucked into the engine if the purge valve is stuck open.
 

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2003 Deville
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Discussion Starter · #3 ·
It could be a cannister purge valve problem.
During refueling the cannister gets fuel in it that is then sucked into the engine if the purge valve is stuck open.
I found some old threads with a similar problem and the solution was replacing the "EVAP Purge Solenoid". Is this the same part?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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72,985 Posts
The fuel pump should run for 2 seconds at Key: ON - that brings fuel pressure in the rail up to about 45 pounds and the pump check valve holds that pressure for a while. When you attempt to START the pump runs and as the idle speed passes 450 rpm upward the fuel pump latches ON and runs constantly. After a fill-up - with power and signal - there's no way fuel could not reach the injectors - that pump will push over 100 psi into a dead head, thus the fuel pressure regulator on the fuel rail.

No need to touch the gas pedal when you start the car. Start-fast idle-idle is totally electronically controlled and doesn't need any outside help.

See if simply turning the key to START - no gas pedal - helps anything.

IF the EVAP purge solenoid at the throttlebody sticks open then it would create an excessive vacuum leak - lean fuel mixture - BUT low speed driveability would be horrible.

Check the green test port cap for tightness - in the black EVAP line near the brake booster.

2002 EVAP.gif
 

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2003 Deville
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62 Posts
Discussion Starter · #6 ·
Thank you! And thank you to CSIMME01

I had the EVAP Canister Purge Valve replaced and he problem stopped. I don't know if there was something wrong with the valve or if this was just an expensive way of checking the connections, but I repeated the triggering conditions twice: drove to 1/4 tank, filled up, no stalling.

But the code I thought was connected with this problem but had stopped, came back (P0446)
This code had been popping up for months prior and I had not tried to have it tracked down, just cleared it.
When the "stalls after fill up" problem started, the code stopped, but now the problem has stopped and the code returned.
It seems the problem condition masked the code, but what is their exact relation?

I love this car. Long trips in hilly PA, maintaining 80 on the upgrades, 22mpg. If I let the speed fall off to 65-70 on the upgrades, 25mpg average. Watching instantaneous fuel consumption I see just how expensive flying uphill like that is. But it's just so satisfying. They need to shave some of the hills out of PA, more like the Jersey Turnpike.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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P 0446 - System Vent Control circuit fault.

Vent valve, wiring, electrical connector.

Separate from the Purge Valve and lines.
 

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2003 Deville
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62 Posts
Discussion Starter · #8 ·
P 0446 - System Vent Control circuit fault.

Vent valve, wiring, electrical connector.

Separate from the Purge Valve and lines.
But... recurring code which stopped when the hard-start-on-refueling started, then started again after the hard-start problem was corrected, seemingly by replacing the purge valve. The causal connection may not be prima facie obvious or prima facie plausible, but however improbable seems less improbable than the possibility that this timing was purely coincidental.

As Sherlock Holmes was made to say by Conan Doyle -- when we have eliminated all other possibilities the remaining one, however improbable, must be the correct one. In this case we have two remaining.
 

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2011 CTS4 Coupe, 2014 ELR, 2018 XT5 AWD
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But... recurring code which stopped when the hard-start-on-refueling started, then started again after the hard-start problem was corrected, seemingly by replacing the purge valve. The causal connection may not be prima facie obvious or prima facie plausible, but however improbable seems less improbable than the possibility that this timing was purely coincidental.

As Sherlock Holmes was made to say by Conan Doyle -- when we have eliminated all other possibilities the remaining one, however improbable, must be the correct one. In this case we have two remaining.
FYI Certain codes will not set when other codes are present.
In this case the P0446 code will not set when there is a canister purge valve fault (P0443)
The dissaperance and reappearance of the P0446 is not coincidental at all.
 

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2011 CTS4 Coupe, 2014 ELR, 2018 XT5 AWD
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Thank you! And thank you to CSIMME01

I had the EVAP Canister Purge Valve replaced and he problem stopped. I don't know if there was something wrong with the valve or if this was just an expensive way of checking the connections, but I repeated the triggering conditions twice: drove to 1/4 tank, filled up, no stalling.

But the code I thought was connected with this problem but had stopped, came back (P0446)
This code had been popping up for months prior and I had not tried to have it tracked down, just cleared it.
When the "stalls after fill up" problem started, the code stopped, but now the problem has stopped and the code returned.
It seems the problem condition masked the code, but what is their exact relation?

I love this car. Long trips in hilly PA, maintaining 80 on the upgrades, 22mpg. If I let the speed fall off to 65-70 on the upgrades, 25mpg average. Watching instantaneous fuel consumption I see just how expensive flying uphill like that is. But it's just so satisfying. They need to shave some of the hills out of PA, more like the Jersey Turnpike.
The P0446 code was not able to set as long as there was a canister purge solenoid fault. (That info comes from the service manual)
Now that you fixed the canister purge problem you are now being told about another problem. As Submariner409 said you now need to look at the vent solenoid to see what's wrong.
 

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2003 Deville
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Discussion Starter · #11 ·
The P0446 code was not able to set as long as there was a canister purge solenoid fault. (That info comes from the service manual)
Now that you fixed the canister purge problem you are now being told about another problem. As Submariner409 said you now need to look at the vent solenoid to see what's wrong.
Well, thanks again for pointing me in the right direction to fix the refueling problem -- that was a solid base hit. I went ahead and had the vent solenoid replaced and that brought the batting average down to 500 as throwing this part at it did not keep the code away. I guess it will now require actual diagnosis.
 
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