Cavalier won't take filling

[dgwak]

I can't put any CNG into my 01 Cavalier all of sudden. I went to 3 different stations but no dice. It just takes a quarter gallon at most and that's it. I know it is empty because I drove it down to the point where it switched over to gasoline last week. Now it's only running on gasoline but no red LED indicator comes on. Just to make sure, I smelled the exhaust. It is only running on gasoline.

The only thing I can think of is the fill valve may be malfunctioning. If so do I have to depressurize the system first to get the fill valve out? What else could cause this?

Any help would be appreciated.

[Luke]

Re: Cavalier won't take filling

Where are you located?

[siai47]

Re: Cavalier won't take filling

Your Cavalier won't take any fuel because it is already full. The fact that it is running on Gasoline without a light on the "fuel" switch lit and there (I assume) is no check engine light, indicates that the AF ECU isn't getting power. The first check is to open the hood, locate the fuse box on the drivers side of the car, locate the fuse marked "CNG" remove it and see if the wire inside is broken. If the fuse is good, re-install it, looking carefully when you insert it back into the box. You should see a small electric arc when you plug it in. If the car still refuses to start on CNG the next check is the fuel relay. Locate the relay and replace it. This is a standard relay that can be purchased at a auto parts store. One of these two things should be the problem, if not, things start getting more costly. If the AF ECU is getting power but something else in the system (other then the ECU) is causing a problem, you should get the red light and a check engine light. Let me know what you find.

[dgwak]

Re: Cavalier won't take filling

Siai47, you were right on!

Yes I feel dumb but indeed it was the fuse. I got confused because the fuse must have been blown right after my last fill. Since the red light didn't come on I have been running on gasoline, not CNG, till it ran out. So no wonder my CNG tank won't take filling. It was full already.

So yes don't assume anything. Just check your fuse first. Silly me!

[darress]

Re: Cavalier won't take filling

siai47, that was a great post to help a fellow cng user. I love to see stuff like that! The dealer would have squeezed him for over a hundred bucks I bet.

[Matt Hopkins]

Re: Cavalier won't take filling

OK, so where is this fuse and how do I recognize it? I just got my 2001 12 passenger van and have no documentation on it at all. I'm guessing that the stock owners manual does not list a CNG Fuse.

[Frank_Sm1th]

Re: Cavalier won't take filling

My 01 Cavalier has its CNG fuse right in the regular fuse box under the hood. Each fuse position is printed on the plastic cover on the fuse box and the CNG position is labeled "CNG". Are you by any chance related to the Hopkins VW family?