Gas pump stops

Adjustso3

Well-Known Member
#1
Hello everyone. I have a 2003 Trailblazer 4.2 LTZ. The very little time it was running last winter, when I went to fill up the tank the pump would stop every few seconds. This summer when I fixed the electrical problems, it filled up with no problems. Now that the weather is cold enough to snow, the pump is stopping every few seconds again. I did change the vent solenoid located at the back of the tank and the pump still stops every few seconds. Does anybody have any ideas why it would fill up fine in the summer and not in the winter ? I turn the engine off when I fill up all the time. I’m a bit confused why it only acts up when it’s cold outside. Any ideas ? Many thanks in advance.
 
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Adjustso3

Well-Known Member
#3
Thanks for your reply. I’ve actually tried different pumps and gas stations. I’ve also gone to the same pump at the same gas station and still get the pump nozzle stopping every few seconds. Gas never rushes back out, it just stops. This is very strange. The only difference is warm weather it’s good to go and cold weather it takes forever to fill.
 

Mike534x

Well-Known Member
#4
Could be the vent for the tank being blocked, or the filler neck. There is a post here from the OS with a bulletin regarding the problem and how to fix it. Had the same issue with my first Envoy, it would fight to fill up on cold days or cold starts. My problem ended up being the fuel filler neck.
 

Mike534x

Well-Known Member
#6
OS is referred to the "Old Site" before GMT became its own thing.
 
#7
Before Vertical Scope raped trailvoy and killed the site we all had worked so hard to build build. The OS is the library of what we did in the past, but most of the reference material has come here over the years.
 

Matt

Silver Supporter
#8
@Adjustso3 I had the same problem but it turned out that the upper filler neck was kinked on my 02. Went to the junkyard and every early model had the same issue but I found an 06 with a non-kinked neck and it fixed the problem. Might be worth a look.
 

Redbeard

Well-Known Member
#9
Same problem here on the '04. Seems to be pump related-those that can pump quick shut it down within a few moments of starting. When I start to fill slowwlly then I can increase the nozzle flow rate quicker. Mine doesn't seem to be temp related at all (but I am in florida though.) The WAWA's pumps seem to be the worse offenders tho.
I like the idea Matt has to check for a non-kinked neck. It's been years since I looked at the hose, but didn't recall being any kink on mine, but now I'll probably go look at it again.
 
#10
A windshield washer jug cap under the handle fixes the problem. The Sierra does this all the time but the utility body filler neck is long as hell and only about half inch in diameter. The cap slows it down just enough.
 

DocBrown

Well-Known Member
#11
I had the same issue with my old TB at some pumps. Occasionally with my Sierra. It's caused by splash back on the nozzle. Not sure why cold weather would cause it. The solution is to pull the nozzle out 1/4 to 1/2 inch. Then I could open the pump handle full.
 

BrianF

Well-Known Member
#13
I had the same issue, no associate codes. Was abysmal in the summer and even worse in the winter (brings back flashbacks of trying to fuel a 130 liter tank on a F250 gasser in -30 C one click at a time...) Anyways, I crawled under the Tb and tapped the vent solenoid with a wrench or something numerous times. A large amount of dirt and debris fell out. I then slid it off its clasp and tipped the vent side down and continued to empty dirt from it. Has been working great for months now.
 
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Adjustso3

Well-Known Member
#14
BrianF, are you talking about the solenoid located towards the back of the gas tank or the solenoid midway by the fuel filter in front of the tank ? I replaced the solenoid that’s located on the back of the tank with a new one.
 

Drec

Well-Known Member
#18
I have a similar problem with my 02 Envoy. What I do is turn the nozzle upside down, so the hose is pointing up and then the nozzle is resting on the top of the gas filler door. Since I started doing this, I haven't had the problem with it shutting off.
 
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Adjustso3

Well-Known Member
#21
Thanks Mooseman, so true ! What doesn’t make sense to me is it filled just fine on the same pumps I go to in the summer and fall. As soon as it got cold out ( snow temp ), the problem came back like last winter. It just doesn’t make sense to me.
 

budwich

Well-Known Member
#23
"holes" get smaller when cooled... law of physics... :smile: during the summer, there is "enough expansion" to allow proper air and liquid flows. In cooler temps, the "passages" (somewhere) have restricted enough to cause those same flows a "bit of resistance" which the sensor / vacuum diaphram in the pump is detecting and shutting off the flow. Your "mission" is to find that restriction... which is maybe in the hose.

Maybe replace the vent solenoid hose itself or run a wire (aviation wire) into it to try clean it out a bit.

As a side note, just saw an inspection camera at costco here for $50ish. :smile:
 
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Adjustso3

Well-Known Member
#24
Thanks Budwich. I never thought of checking the vent solenoid hose. Maybe there’s something in there. It’s snowing like crazy where I live and the snow is piling up. Yes I have checked the filler neck to the tank and all looks normal. No kinks. I just may have to deal with it for the winter and check it out in the spring. Thanks for all the reply’s.
 
#25
My old '03 Envoy was doing the same thing and it was also the filler neck. I got under and inspected the original filler neck, and it looked completely normal. Rusted to crap, but looked fine from the outside.

Anyhow, I bought one of * these on ebay * and installed it. Filled up fine after that.

One thing that happened though was the plate and screw(s) holding the assembly behind the fuel door rotted away and I had to make my own brace from a piece of sheet metal to re-secure it to the frame. Wasn't pretty, but wasn't visible, so I didn't mind.
 

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