tmillz1293

Hello! I have a ‘92 G30 Sport Van and since I bought it the fuel tank is very hard to fill up. As in the pump keeps clicking off. The fuel filler neck looks in good shape and pretty simple as well so I’m not exactly sure why this would happen.

I have been seeing online that in later vehicles the EVAP system can get clogged up and cause vapors to not vent properly during fill up but I’m not sure if this van even has that system. And I can’t find any info on where that would even be located on the van. Anyone have any insight on this issue??

mountainmanjoe

EVAP systems have been required on gasoline powered vehicles since the 1970s.
If you look in any online part catalog for your van model, you will find EVAP system parts (such as Vapor Canister Vent Valve)



The problem is the fuel tank vent. The nozzles at your gas station operate on pressure. When your tank can't vent, filling it up causes the vapor pressure inside to rise, triggering the nozzle to turn off the gasoline flow.

The EVAP system can fail in several places. There can be a blockage in the vent lines, the charcoal canister, the vent valve, etc..
The components should be right next to the fuel tank. I'm sure you can find some Youtube videos. Make sure that they flow freely. Some people use smoke machines.
Unfortunately your van predates OBDII, which makes things harder to diagnose. You'll have to operate the solenoids manually to see if they work.

I've even heard that spiders are attracted by the smell of gasoline, and they build egg pouches inside the tubes.

tmillz1293

Thank you for the info! I was thinking it must be something to do with that EVAP system and after I wrote this post I tried gassing up again when it was really quiet and could ac to ally hear gurgling which must be a symptom of a clogged vent system. The filler neck filled all the way up to the very too(which is odd) and then I shook the van a bit to break loose any air bubbles and it went down. So I agree with you fully that it must be a bad vent. I will try getting a new valve and replacing it though I’m not sure where it is. It appears to be in a not so ideal location on the passenger side suspension from what I’ve heard so it might be a bear.

I am probably going to go ahead and replace it no matter what becuase there’s clearly something wrong with the system anyways, but do you think it would be wise to blow some air through there via a small air compressor to potentially blow out any clogs? Or do you think that would make any potential issues even worse. This would be after I swap the valve

Also for the record: this is the valve you’re referencing correct? https://www.oreillyauto.com/detail/c...olet-g30?pos=0

As I was researching this I saw some modern chevy trucks and probably the express vans have a much more complex unit and this seems like just some stupid dinky connector that seems super simple. So I just wanted to ask and make sure you aren’t referring to something else. I’ve worked on a lot of cars but have never had to deal with this EVAP system before.

thank you again, Joe

mountainmanjoe

You shouldn't fill your tank to the filler neck ever. Gasoline gets into the vent lines and charcoal canister.

The part in your link is the PURGE valve. Vacuum from the running engine draw vapors into the engine intake where it is combusted with normal air/fuel mixture.
I only mentioned the vent valve as an example component of your EVAP system, so you could find it in a part catalog and prove to yourself that your van has an EVAP system.
Your valve might be perfectly fine.
As I explained, a blockage ANYWHERE in the venting system can cause your problem. It's up to you to test and find it. It may just be the filler neck since it's the most exposed.

The system isn't that complex. This topic might clear some things up:
https://chevroletforum.com/forum/tra...system-103062/

tmillz1293

Believe me, filling it up that high was not intentional plus it went down to a normal level once i shook the van to “burp” the tank.

Thank you for the clarification and the link on EVAP systems I’ll check that out!

Would running some compressed air through these vent lines do any damage though? If it’s just a matter of popping a vent line off and blowing it out rather than spending money on parts that may or may not be bad I’d rather go with the free option.

mountainmanjoe

Maybe if you have a regulator but the system was not designed to have 100psi blasted through it. Especially old degraded hoses.

If you read the link I posted there are troubleshooting steps there. Most shops use a smoke machine and bidirectional diagnostic tool to test the EVAP system.

tmillz1293

Yeah I read it since I made my last post and it looks like the compressed air is a no-go. And yeah jeez the hoses are probably fried. A lot of the seals and the tires are totally fried from the sun(got it from Eastern WA). So I bet the hoses aren’t exactly top-notch anymore.