Natural gas poping / clicking under hood?

[Royger]

I just bought a CNG vehicle. 1995 Chev Lumina conversion. Converted in 2001. When I picked up the vehicle it has 2200 psi. I drove it and heard noise under the hood. It didn't seem like a concern to me. I filled the tank to 3500 psi. I drove away from the gas station. Every time I stepped to accelerate I heard popping click or knocking located where the Compuvalve is located. Also the High pressure regulator / Relief valve is located straight under the Compuvalve. Could it be that I put too much pressure in. When I accelerate the popping is loud, as I use more gas it starts to go away. My pressure gauge goes down to 2000 psi and then I don't hear the noise at all during acceleration. Do I need to get it serviced? Is this normal? Thanks guys.

[Highmarker]

Re: Natural gas poping / clicking under hood?

I believe you need to replace the relief valve. I have a buddy who has the same problem with his 1999 Chevy Cavalier. He is replacing the relief valve this weekend. I'll let you know if this fixes his problem.

Jared.
Roy, Utah

[Royger]

Re: Natural gas poping / clicking under hood?

Please let me know if that works. I'm still looking for a place to get parts. Where do you go for parts (In Utah, Salt Lake). I would also like to know how much the part was he had to replace. Thanks!

[Curtis]

Re: Natural gas poping / clicking under hood?

Royger, look up SnoMotion in the section of the group where the auxilliary tank installers are listed. They're a conversion company,in Utah, that can probably assist you.

[Highmarker]

Re: Natural gas poping / clicking under hood?

We purchased our parts from Young Chevrolet in Layton (they are an authorized AFV dealership). We replaced the relief valve, but it didn't fix the problem. So I think he is going to replace the high pressure regulator. On the Cavalier, the relief valve is connected to the high pressure regulator. Where your car is conversion, Rick Oliver at Sno-Motion is a good place to get parts.

[Royger]

Re: Natural gas poping / clicking under hood?

Replaced High pressure regulator and that fixed my problem!

[mickael]

Re: Natural gas poping / clicking under hood?

What much does a HPR cost when replacing? $ $ $

[Royger]

Re: Natural gas poping / clicking under hood?

I found one on ebay for $400. I got lucky that someone was selling one at the same time I needed one. SnoMotions had one for $500. My High pressure regulator was an older modle. The system was installed in 1996.