[ELDORADO2K]

I found a this post online from a guy who said he was having problems at the gas pump. His issue involved the gas pump continuously stopping the way it does when the tank is full. I sometimes have this same issue when pumping gas in my 02’ DTS.

Anyways, can someone help clarify what exactly he’s talking about?
The next post will be a copy/paste of the exact words from the thread I found online.

 

[ELDORADO2K]

[OP]

I try to fuel my 97 Deville and all it does it keep kicking off the nozzle. It took me forever to pump 18 gallons the other night. I ended up barely squeezing the trigger just enough to get it to flow otherwise it would just pop.

It has done this before at the beginning of the season but seems to improve throughout the season. Well this year I want to figure it out. IIRC the canister is at the left rear somewhere. I had the tank down when I replaced the fuel pump module and there was nothing obvious there. I know I am not the only one that has had the issue. This is the first cadillac I have run into this issue with. Not sure if it is the vent solenoid, hose, canister... Hopefully just a blockage in a hose somewhere.


[someone replies to him]


I occasionally get an early click-off if I'm fueling and the gas nozzle is at an up and down (12 o'clock/6 o'clock) position; if I tilt the nozzle to about 10 o'clock/4 o'clock my fill usually does a lot better. Certain nozzles, also, seem to be more prone to doing this (if you typically fuel up at the same station, same nozzle, try a different one). This happens (sometimes) on my '04 Olds Bravada as well as my '17 XT5. Hope this helps; may or may not be your problem.


[Original poster next, he posts this]


Today I finally took a few minutes to work on the fuel issue and I found a very obvious problem but have no idea if it can be related to the fuel fill issue.

I replaced the purge valve(engine bay) which is the only sensor I found listed and when I went to replace it I found that the nipple that comes off the valve and goes to the intake was broken off and had cracks throughout it.

I guess I will find out tomorrow if it makes any difference.

Surely must have caused a vacuum leak as the vacuum comes from the intake.

Next step is to pull the lines off the canister and see if there is any issues there.

Did I mention I dont know what time is?

Update. Fueled up this morning. never clicked off at full flow. 17 gallons. Will have to keep my fingers crossed

 

[ELDORADO2K]

What does he mean by “purge valve”?
Is he talking about the purge line that goes to the coolant reservoir tank? Or?

 

[Submariner409]

It's all in the GM/Cadillac service manuals - a www.alldatadiy.com online service. Or, you could Google "cadillac forums northstar evap system" or something close.

You're confusing the EVAP system with part of the cooling system. EVAP stores fuel tank vapor for later burning, then sends it to the intake manifold by opening a purge valve on the throttlebody and opening a fresh air vent at the charcoal canister - the resulting vacuum then moves fresh air through the charcoal canister to move the vapor into the intake manifold for mixing with the air/fuel charge. EVAP operates at steady speeds over 30 mph.

A clogged EVAP canister vent solenoid line will cause premature fuel pump shutoff - not at all common in our cars. Common in Escalades because the charcoal canister isolation screens break and the pressure/vent/suction/vent action moves charcoal granules throughout the system.

You need to get into the service manuals to find out how all this stuff works ......... "it's in the book" !

Our fuel fill pipes have flow restrictors in them - mainly to prevent siphoning fuel from the tank - it's either a small orifice or a fine screen. High fuel pump flow can trip the auto shutoff. Our fill pipes also have an internal vent pipe that runs from the tank top top the upper end of the filler pipe - inside the pipe, after the cap. Look at the pictures in RockAuto, INFO tabs.

 

[rodnok01]

My 97 is a picky SOB on fill ups, kicks off before full every time and has done so since 30k when I aquired it. There must have been a design change in 98 as the 98 isn't picky at all.