[DougD]

I have an '01 that was acting up for quite some time. It would start up very easily -- idle nicely for about 10 seconds -- then stop -- just as if it had been turned off.
I thought it was to do with the primary and booster fuel pumps -- perhaps the primary was not working and the engine was startiing on the booster pump -- then dying when the booster pump shut down after cycling at start up??

Somewhat by accident, I started the engine after a friend disconnected the fuel tank pressure sensor - thinking he had disconnected the fuel pumps.

The engine not only started (I was surprised - as I thought the pumps were disconnected!) but it continued to run - idling very nicely for several minutes.

I purchased a new fuel tank pressure sensor (AC Delco #16238399 $8.16) and installed it today. Temperature outside was warm enough to permit the garage door to remain open - so I started the car and it started nicely -- and continued to run!

Something for others to check if they run into this start - then stall issue

 

[G8nightman]

:clap:

 

[jtrealty]

From looking at the manual it doesn't make sense that a bad tank pressure sensor would prevent the motor from running. Many sensors can fail and cause an error code but the motor will still run, maybe not in "Closed Loop" but still operate. I suspect you touched something else that is the real problem like a bad connection to the fuel pumps. On start-up both fuel pumps are run to "exercise" the secondary pump. If the primary pump is not working the motor would shut down quickly just as soon as the secondary pump stopped. Shake the wires to the fuel pumps and see if the motor stops.
David Teitelbaum

 

[DougD]

I thought the same thing, David.
I have had this issue for quite some time. I had connected/disconnected the fuel pump connector several times.
I was getting no CEL's.
It was a bit of a fluke that the Fuel Tank Pressure Sensor was un-plugged - then the car started (and ran). I did, then, get a CEL with 3 codes, all related to the fuel tank pressure.
Like you - I couldn't believe this faulty sensor could lead to an engine shut down.
It may not have been the culprit -- however, the timing and apparent fix certainly coincided!

 

[carbuff]

Glad you found it, Doug.

And you may have helped others who could disconnect that sensor as a diagnostic.


HERE'S AN APPROPRIATE COMMENT FOR TODAY (St Patrick's Day):


Why shouldn't you iron a Shamrock?

















WAIT FOR IT....
















You don't want to "press" your luck! rotfl rotfl

 

[Viggen]

Lol..... That's really bad

 

[jtrealty]

I thought the same thing, David.
I have had this issue for quite some time. I had connected/disconnected the fuel pump connector several times.
I was getting no CEL's.
It was a bit of a fluke that the Fuel Tank Pressure Sensor was un-plugged - then the car started (and ran). I did, then, get a CEL with 3 codes, all related to the fuel tank pressure.
Like you - I couldn't believe this faulty sensor could lead to an engine shut down.
It may not have been the culprit -- however, the timing and apparent fix certainly coincided!

One way to confirm the diagnosis would be to reinstall the old sensor and see what happens. I mention this because often in "mucking about" you disturb things and what seems like the "fix" doesn't last because it wasn't. In any case it isn't the first undocumented failure mode and surely won't be the last. Maybe the ECU plug wasn't in just right or the plug to the fuel pumps, there is a lot going on in that area.
David Teitelbaum

 

[s2kseven]

Well...as far as i know the fuel tank sensor measure the over pressure of the tank and relay it to the ECM. If there is excessive fuel tank pressure, it will force the system to purge.
So...if the fuel tank pressure sensor is not connected -- somewhere along the line the ECM was not receiving input and going default.....and that default could be engine stall.

 

[Wayne Ellison]

The pressure sensor is part of the evaporation control system. The ECU needs to calculate the acceptable pressure leak down rate to in order to detect small/large leaks. Purging is done to purge the gas fumes captured in the charcoal canister.