OBDII problems with aftermarket conversions

[CNG Utah]

Attached is a copy of a technical bulletin that was sent out to all Utah County IM stations recently. At the bottom of the first page and beginning of the second it says that they've been seeing a lot of conversion that cheat the system because the aren't OBDII compliant and they are setting off check engine lights. The bulletin claims that these vehicles running on gaseous fuel are often dirtier (I call BS on that).

I just want to keep people informed as I've seen some aftermarket conversions that didn't seem to take the OBDII system into account and just has a check engine light (MIL) on the the whole time. These probably will have a lot of difficulty getting registered in the near future.

I've also attached the emissions report for a 92 CNG Dodge Van we recently tested. Because of the age it had to be tested using the tail pipe probe. Notice the results of the high speed test. It could have passed with 220 ppm Hydrocarbon and it got 1! With CO it could have passed with 1.2 and it got .01. Just thought I would share.
-Derek

[rtry9a]

Re: OBDII problems with aftermarket conversions

Fortunately it looks like this extremely shortsighted approach to natural gas registration only applies to Utah county. You guys should write some letters to your commissioners...

Id be extremely surprised if any natgas application that runs smoothly would not run cleaner than any gasoline fueled vehicle. The County should simply confirm that the vehicle passes emission and safety standards.

[Luke]

Re: OBDII problems with aftermarket conversions

Something else to realize is that Utah County decided to make Diesel fueled vehicles exempt from emissions.

excerpt from: http://w2k2.co.utah.ut.us/Dept/Healt...etin2005-3.pdf

DIESEL I/M PROGRAM TERMINATION
On November 1, 2005 the Utah County Commissioners unanimously voted to repeal the Diesel I/M
Program Ordinance. As of January 1, 2006 all diesel powered vehicles registered in Utah County will be
exempt from an I/M inspection. Only those vehicles with a past due registration date prior to January 1 will
be required to have an inspection performed after the first of the year.
This change applies only to vehicles registered in Utah County. Representatives from Salt Lake and
Davis County have indicated that they will continue to require diesel powered vehicles to be tested

[j03j03]

Re: OBDII problems with aftermarket conversions

I personally haven't had any problems with emissions and OBDII. I have a converted 1996 Ranger and even though i didn't need to I had the emissions tested. Passed with flying colors! I wonder if it's just a certain company like GFI that doesn't have the OBDII problems. I don't know one way or the other on that. Just a thought.
Now in the way of an OBDIII it won't happen for at least another 10-15 years. The newest thing out right now is CAN-OBDII. Just means the computers comunicate faster.

[Devo]

Re: OBDII problems with aftermarket conversions

When I had our Bi-Fuel Contour tested in South Jordan, they didn't even check it in CNG mode. They told me that they were only supposed to check it running on gasoline.

[vaughnr007]

Re: OBDII problems with aftermarket conversions

My understanding is the IM requirements are set by the Health Department for each county and not by the state. It sounds like the Utah Health Department needs better expertise on CNG use then they're getting.
Robert

[Yroc]

Re: OBDII problems with aftermarket conversions

Doesn't mattter. Run on regular gas to pass the test, get a certified mechanic to sign a statement that the vehicle runs properly on CNG and that's all you need. We have a 2000 escalade and a 2000 durango and both trigger the check engine light on CNG. Not becuase it's running poorly, but because it doesn't know what's going on. It's always the MAF (venturi conversion). I assume a little CNG is getting read there??

It's really not a problem as far as I can tell. Any other experiences???

[avi8r]

Re: OBDII problems with aftermarket conversions

It appears that bulletin is no longer on the website (last TD listed now is 2007-1). Is it located in another area, or have they come to their senses and rescinded this policy?

[Marka]

Re: OBDII problems with aftermarket conversions

The technical buletin is still on the web site. I have attached a test that was run in Arizona 11/29/07 the results show the CNG running almost 4 times higher than Gas. Granted the NOX reading is lower but that makes perfect sense with a richer fuel ratio on CNG. Also this was a EPA certified convertion installed by a Dodge dealership in AZ

[midijeep]

Re: OBDII problems with aftermarket conversions

Still on website as of July 25, 2008

http://w2k2.co.utah.ut.us/News/DeptN...HEALTHENVIRAIR

[midijeep]

Re: OBDII problems with aftermarket conversions

OK, just talked to a guy at Utah County air quality. A CNG kit is ok for now but will need to pass both gasoline and CNG emissions. He did stress that since all this is new to Utah, things could change where you will need to provide proof that the CNG kit is certified by either EPA or CARB. He said the person installing the kit would have that information.

If f anyone has additional information please pass it along.