I would appreciate any advice that 850 GLT owners can give... I have a 1996 850 GLT that just barely failed the California Smog Test for slighly high NOx. I took the car to a 'Gold Shield' Smog Station (certified by the State) for diagnosis and repair. Unfortunately, the Smog Station has been unable to fully diagnose and fix the problem. They have checked the Cat. converter, the O2 sensor, all vacuum lines, and all were fine. (The car is not equipped with an EGR valve.) They have replaced the Air Mass Meter, flushed the entire fuel injection system (claiming that carbon build up within the cyclinders can cause higher compression which will generate NOx), cleaned the flame trap and throttle body, replaced the gas cap (big deal!!) and continued to diagnose the issue. They now claim that the car needs to be driven >200 miles in order for the computer system to reset itself. My wife has driven the car >300 miles and last Saturday, the Smog Station checked the computer system and it still has not reset itself. I have two simple questions: (1) Has anyone had this much trouble getting an 850 smogged? and (2) The odometer broke several months ago. Does anyone know if the computer system is in any way linked to the odomoter... Perhaps that is the root cause of the computer system not resetting itself?? The Smog Station claims that Volvo will not provide them with any help. Can anyone help me to solve this mystery or is it a simple case of just being ripped off?
Many thanks,
Only Volvo

One very common problem on the non turbos that can cause this problem, as weel as poor performance, low MPG, engine pinging and damage to the MAF sensor is the hot/cold air flap valve on the bottom of the airbox. It fails in the hot air only position and will cause high NOX and the engine does not get all the air it needs trhu the intake. Also, the hot air will cause the MAF to fail prematurely. Check that out.
Icelandic

From Matthews volvo site, written by MadeinJapan:



Joined: 31 Mar 2005
Posts: 6354
Location: Knoxville, TN
Posted: Sun Mar 16, 2008 3:31 pm

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If you are having trouble getting your 850 through state emissions test and the source of your frustration is ‘readiness’ codes that aren’t set, the following procedure from Volvo will help set the readiness codes.

Start with the vehicle cool, below 122 degrees F.
Turn off the air conditioning.
Select a location where the driving can be done without violating traffic laws and you can stop safely at the side of the road.

1. Start the engine and accelerate to approximately 1500-2000 rpm.
2. Drive for 6 minutes at 1500-2000 rpm.
3. Stop the vehicle and remain at idle in drive for 70 seconds.
4. Accelerate to at least 45mph and drive for 5 minutes at 1800-2200 rpm.
5. Stop the vehicle and remain at idle in drive for 60 seconds.
6. Accelerate to at least 45 mph and drive for 4 minutes at 1800-2200 rpm.
7. Stop the vehicle and remain at idle in drive for 60 seconds.
8. Park the vehicle and turn off the engine.

This procedure must be performed TWICE from a cold start to set the readiness codes.

Some people say that if doing it twice doesn't get it, do it a third time.
Just driving around for a week or two, getting on the highway, stopping for groceries, etc. will also work if you have the time.

Pulling a battery or repairing or replacing a sensor could cause your car to not show the desired readiness codes. If you have frantically worked on your car to get it ready for an inspection, take heed. Probe your ECU with a scanner and do the drive cycles to avoid a headache and $$ at the inspection station.
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While this was for a 1998, it will also work for a 1996. There is a "problem" with setting the codes for drivability for the 1996-97 models, some ECUs will never "set" and the State of California knows this. The inspection station should have been aware of this, it is in their notes and exempts these cars.
Search for Brickboarder 'FIXIT2003' and send him an email about this. His service station is located in the LA area and is very honest.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)