1999 Chevy Cavalier tank full but shows empty and won't start on CNG

[Philster]

I have a 1999 Chev Cavalier and after filling it the night before, it would only start on gasoline. I pushed the button and the CNG shows empty. I tried to fill it thinking that I possibly had a leak and it would only take 30 cents. I checked all the fuses and they are OK, so now I am thinking it is the sensor that tells the car that there is no CNG in it. I don't know where to look or what to check... Any advice would be helpful.

Phil

[siai47]

Re: 1999 Chevy Cavalier tank full but shows empty and won't start on CNG

Most likely the fuel pressure transducer is not reading correctly. If you know where it is located, try giving it a tap to see if the gauge will respond. If that doesn't work, remove the connector at the transducer and see if it will start on CNG. Sometimes that will work. If it will start and run on CNG, (red indicator on the fuel switch off) try re-connecting the transducer after driving for a while and see if the gauge is working.

[Philster]

Re: 1999 Chevy Cavalier tank full but shows empty and won't start on CNG

Thanks,

Can you give me any idea where the transducer is located?

Phil

[siai47]

Re: 1999 Chevy Cavalier tank full but shows empty and won't start on CNG

The transducer is fitted to the high pressure lockoff valve assembly which is screwed into the CNG tank in the trunk. There is a large rubber boot covering the entire end of the tank on the drivers side of the car. This boot needs to be rolled back to see the valve. The transducer is a silver tube about 3/4" in diameter and a couple inches long with a three wire connector plugged into it. Before you start, you might want to spend a couple of bucks with a dealer who can scan the car and determine if the pressure information from the transducer is being received at the computer and that it is correct. The scan can also determine if the computer is supplying the 5 volt power required by the transducer to operate. As you are located in Utah, there are many members on this site who might be close to your location and be able to help you with this--both with finding the transducer and helping to resolve the problem.

[Philster]

Re: 1999 Chevy Cavalier tank full but shows empty and won't start on CNG

I found the transducer and tapped it and unplugged without any success. I guess I will have to take it to a technician. Does anybody have any suggestions on a good Repair shop? I live in Central Utah and will be traveling to SLC in two weeks.

Thanks

Phil

P.S. If anyone has any other suggestions I would love to hear from you.

[siai47]

Re: 1999 Chevy Cavalier tank full but shows empty and won't start on CNG

Try Lancer automotive (who is a member on this site) and see if they can be of help.

[nttrainer]

Re: 1999 Chevy Cavalier tank full but shows empty and won't start on CNG

If you are south of Salt Lake you could try Natural Solutions - Lindon - 801-785-6225. Ask for Mike. I've used them for several Cavalier issues and have been very satisfied.