Need a GMS

[alliedmotors]

I need to locate a Gas Mass Sensor, dealer or otherwise. My local GM dealer is trying to find one, any ideas on who may have them in stock?

[Highmarker]

Re: Need a GMS

Where are you located? I know that Young Chevrolet in Layton, Utah might have one in stock.

[alliedmotors]

Re: Need a GMS

California. I called them this morning. None in stock and they quoted list price of $2619. Either the guy didn't hear me when I said I'm a dealer or just didn't care.

[Highmarker]

Re: Need a GMS

None in stock and they quoted list price of $2619.

$2619
Wow, I guess the price of parts goes up just like the price of used CNG cars.
You might want to look at the following thread:

http://www.cngchat.com/forum/showthread.php?t=2659

It seems that there is a guy on here that has/had six gas mass sensors. They are broken, but maybe fixable.

[alliedmotors]

Re: Need a GMS

My local dealer quoted $1584 if they can get one. Then after it's replaced I'll take a closer look at this one to find out what went wrong so I can figure out how to fix them.

[alliedmotors]

Re: Need a GMS

Wow...backordered until November 10th. Can anyone confirm that a GMS from a 2003 Cavalier is the same as for 2001? Seems to be only one part number.

[siai47]

Re: Need a GMS

1999 through 2002 should work. I don't know if there is a difference in the 1998 as it was pre OBDII. 2003 was a different engine so there might be calibration differences. Check with the dealer on superceded part numbers for the sensor you are replacing. You should be able to follow the trail of numbers and see which ones will work.

[Highmarker]

Re: Need a GMS

Can anyone confirm that a GMS from a 2003 Cavalier is the same as for 2001? Seems to be only one part number.

I don't think there is a GMS on a 2003-2004 Cavalier. They use CNG injectors. On my 2003, I have followed my CNG line from the HPR to the low pressure lock off (which is different than the '02 - it is a Parker valve), then to the low pressure regulator (which is also different than the '02), then to the injectors. I haven't seen a GMS on a '03.

[siai47]

Re: Need a GMS

You might be right---injectors for sure on the 2004. I know that the 2003 still uses the dual ECU's like the 1998's and up and the 2004 is the only Cavalier that has a single ECU for both liquid and gaseous fuel. I just thought it was possible that the '03 was still fumigation.

[alliedmotors]

Re: Need a GMS

Doesn't matter, the engine in question was stripped of all sensors. That's what I'm finding for all of these cars that end up at salvage yards. They don't know what they are, so they throw the other components away.

[contour2000]

Re: Need a GMS

I searched but did not find...
Please post the part numbers for the GMS, or part number for each year range?
I have a 2001 cav now.
thanks in advance.

[siai47]

Re: Need a GMS

Just about any GMS/MCV that you find that looks like the broken one should work. They were used in Cavaliers up to 2002 and in various pickup trucks. Usually the mass airflow sensor inside the unit fails either due to corrosion or mechanical breakage. If you take your time, you can get the GMS apart to get a closer look at the sensor. Be careful as there are dual circuit boards, several different sized screws, insulating tape from components to the housing (causing things to stick), etc. Once you get the interals laid out on a table take a close look at the sensor to make sure the wire isn't broken or corroded off at the bottom. It sits in a little well in the housing that collects crud that can also short out or change the calibration of the senor. Sometimes all that is needed is to clean up the well and the sensor with a MAF (mass airflow sensor) spray cleaner. I think one of the members here used to repair these.

[CNG Utah]

Re: Need a GMS

Just so you know, we have a guy who can rebuild the GMS for $500.

http://www.cngutah.com/forsale/gms/main.php

-Derek