Hey gang, CNGchat needs your help!

For over a decade we have enjoyed providing this little corner of the Internet for folks to discuss all things natural gas vehicles. It is the largest forum of its kind: with some 70,000 posts on over 11,000 topics. But with continued low gasoline & diesel prices and strong automaker support for electric vehicles, consumer interest in CNG has dropped considerably, and with it has visitor traffic here. As a result, Google ad revenues no longer cover hosting fees.

If you find CNGchat to be a useful resource then please consider making a modest donation to support keeping this remarkable pool of knowledge available to the alternative fuels community. Thanks!

See more
See less

Want to buy 99 Cavalier CNG ECM or sell vehicle that needs one

  • Filter
  • Time
  • Show
Clear All
new posts

  • Want to buy 99 Cavalier CNG ECM or sell vehicle that needs one

    One of my older bi-fuel vehicles (1999 Chevy Cavalier) needs a new alternate fuel ECM. I have been through discussions before and have confirmed the ECM is bad (Tech II analysis/no communication and ECM repair shop has confirmed/they could not fix it). I have been unable to get a used one and I'm not interested in paying the price for a new one. I believe an ECM from 1999 - 2002 would work from either a bi-fuel Chevy pick-up or another Cavalier - might need to get it reflashed if it is not from the same model.

    The only reason I want the ECM is so I can fix the CNG system and sell the vehicle fully working. It runs fine on gasoline.

    Vehicle details:

    1999 bi-fuel Chevy Cavalier (Green)
    140,000 miles
    HPR was replaced a couple years ago (buyer may have the old one if you want it)
    Needs a new AC compressor (I can replace this but would want the parts cost differential)
    Full set of factory manuals
    Some small dings and scratches but no major damage or rust and no accidents
    Located in Kansas City area

    I'm thnking $2500.00 for the vehicle. I was seriously considering parting out the CNG system and selling the vehicle as a gasoline only vehicle but I thought that would just take another CNG vehicle off the road.

    email me if you either want to sell a working ECM that will fit (1999 - 2002 bifuel chevy pick-up or cavalier) or you are interested in the vehicle:


  • #2
    Re: Want to buy 99 Cavalier CNG ECM or sell vehicle that needs one

    Have you tried removing the AF ECU and removing the covers and cleaning the board and connector area? Sometimes this will bring them back to life. It's worth a try--worked for me.


    • #3
      Re: Want to buy 99 Cavalier CNG ECM or sell vehicle that needs one

      siai47 - Tried cleaning the board and connector. I've read most of your posts on this topic. The connector contacts were in good shape but the case seal allowed some water into the case - I cleaned up the case, the board and the connector. Also sent the ECM to a specilized repair shop for ECMs and they could not fix it. They professionally cleaned it as well. I've been looking for a working used one for about 6 months and have not had much luck; eBay, craigslist, and junkyards.

      I purchased a few Honda GXs and I want to sell this vehicle. If it was working on CNG I could get a few more bucks but I'm tired of searching for a replacement ECM and a new one costs too much.

      Thanks for your interest. If you think you can fix the ECM I'll be happy to send it to you and pay you for your services (might need to set a limit on this) . Since most of the compoments are surface mount it is probably not cost effectice to repair - the ECM shop was not willing to try.

      Any additional thoughts. Looking for a project vehicle - the car works fine on gasoline?



      • #4
        Re: Want to buy 99 Cavalier CNG ECM or sell vehicle that needs one

        Thanks all. Someone who read this post sold me the AF ECM and as soon as I plugged it in and started the vehicle everything worked great - no issues.