Bleeding a IMPCO/GM system

[mattamhop]

How does one disable an IMPCO CNG system so that my mechanic who has no experience with CNG doesn't disable himself when he works on our van? I started by running the tanks down to "empty", but at 3600psi better safe than sorry. What is the procedure for making the CNG safe for doing work around the injectors?

[rocketmanpete]

Re: Bleeding a IMPCO/GM system

I won't bet the ranch but IMPCO is a CNG default system once it runs out of natural gas it is out,the injectors would be a low pressure side. Anyone disagree

[BRodri]

Re: Bleeding a IMPCO/GM system

I would like to know what vehicle we are working on here. if it is a chevy 1500 then there is a shut off valve before the HPR that you can turn and run the engine till it stalls. then you look at the hpr itself and there might be a nipple valve like the kind used to fill a tire. if that is so then press on the inside of it to relieve any extra pressure. after that it is safe to work around this area. and after you get done you can just flip that shut off valve to get it back on cng.