Failure to pass California smog

stephenschachter · Post by **stephenschachter** » 13 Apr 2022, 14:45

My 1986 Volvo 244 wagon has failed to pass CA smog. It appears that large amounts or fuel is being pumped into the engine causing rich running (runs fine by the way.) It is expensive to have the smog test repeated, so I'd like to replace the likely suspect parts before going for another test. So far the fuel pressure regulator, spark plugs, cat convertor have been replaced. I intend the replace the 2 temperature sensors next. At that point I might try the test again. If it still fails, I'd think about replacing the air mass meter and the computer. Does anyone have any suggestions for an alternative approach? Any ideas appreciated.

Post by **matthew1** » 13 Apr 2022, 17:07

I'm not good with the pre-90s Volvos, but can you post the failure test text? How is MPG? Any tailpipe smoke during acceleration or startup?

I'd add some fuel treatment in your to-do list. Also a good "Italian Tuneup".

Ensure the car is warm when you take it in for the test. 20-30 minutes of driving warm.

Post by **volvolugnut** » 13 Apr 2022, 17:29

If your car still has the flexible hot air tube and thermostat valve in the air intake box, remove them. The air thermostat often malfunctioned and forced hot air into the engine all the time.
volvolugnut

Post by **abscate** » 14 Apr 2022, 14:43

Post up a copy of your smog report.

The data there will guide to you what’s wrong

Post by **kallekula** » 15 Apr 2022, 07:19

+1 on posting the smog result. High CO is often related to bad catalytic converter(s) for example.

Post by **BlackBart** » 15 Apr 2022, 14:08

stephenschachter wrote: ↑13 Apr 2022, 14:45If it still fails, I'd think about replacing the air mass meter and the computer.

Those are expensive steps without knowing the cause. The steps mentioned above by others are next.

O2 sensor(s).....??

454cid · Post by **454cid** » 29 May 2022, 07:36

Get a scanner on it, and look at live data..... o2 sensors and fuel trims, for example.

EDIT: It'll have to be a scanner that will do OBD1. I'm not sure if modern scanners will do that anymore.

Post by **BlackBart** » 29 May 2022, 08:40

Does a 1986 anything have a scanner port? My ‘94 does not.

Post by **matthew1** » 29 May 2022, 10:54

OBD arrived later, and it was under the hood. You had to count flashes of the light. https://www.matthewsvolvosite.com/how-t ... -obd-unit/

OBD-II arrived in 1995 on some Volvos, and 1996 on the rest. That's scanner stuff.

postoak · Post by **postoak** » 04 Jun 2022, 00:46

Sounds like you've addressed a lot of the heavy hitters already (fuel pressure regulator, spark plugs, cat converter). Careful with the MAF, esp if you're thinking of buying new. They're all made in China crap, and you're better off finding a used known working one instead. ECU would be last resort.

For the cat, is it new and CARB / 50-state compliant? If so you must've spent a pretty penny with current prices being heavily inflated - ouch.

Does your coolant temp register on the dash? If so, you're prob good there in regards to the coolant temp sensor.

Check your idle CO mixture (check this thread: http://forums.turbobricks.com/showthrea ... 002&page=1). 86 MAF's (LH 2.2) have the mixture screw, so it helps to check if you're running rich at idle.

How's your O2 sensor? Any exhaust leaks? Have you plugged the hot air tube on the filter box? Make sure to leave the flexible pipe in place to help with passing visual inspection.