1990 won't pass emissions, check engine light codes...

[Terrorizer]

Hi guys, so my 1990 5 speed failed emissions. I checked for codes with the key on, engine off method and it said system ok, but some codes were saved:

18-Ignition TACH signal erratic - Ignition Systems
29- Vehicle Speed Sensor problem - VSS
41- System was lean for 15 seconds or more (no HO2S switching) - Fuel control
46-Electronic Ignition - primary circuit failure coil 2 - Ignition Systems
48- High flow unmetered air (check for large vacuum leak, inlet hoses etc.)
Electronic Ignition - coil primary circuit failure - Ignition Systems

My main concern is do what I have to do to pass emissions so I can get my registration taken care of. Any idea's what the problem may be? thanks for any help.

 

[sperold]

It would help to know what the car failed on the E-test
Erase the stored codes now and see if any come back.
It never hurts to have good plugs and wires, and O2 sensors play a big role in E-testing.
The old codes suggest in the past there were issues with your cam sensor, O2 sensors, vacuum hoses and your coil output, but if they are not current, it is not a sure thing that there is an issue with them now.

 

[rubydist]

41 = lean on rear bank - either you have a bad oxy sensor which is causing the engine to run rich (thinking its lean) or a vacuum leak on that bank that is truly making it run lean. in either case, that will cause problems with emission tests.

46 = coil fault or dis fault. in my experience, its 50/50 as to the real problem. in either case, that will cause problems with emission tests.

48 = coil fault (on my list of codes). the likelihood that 2 coil circuits fail at once is highly unlikely, so it points more toward the dis being bad, imho.

I would replace the dis, look hard for a vacuum leak on the rear bank and either fix that or replace the rear oxy sensor and then re-test.

 

[Terrorizer]

I'm looking at the results now and it failed because of a high carbon monoxide level. My car had 14.34 grams/mile, the maximum is 12.0 grams/mile

 

[SHOdded]

Leaky injectors / high fuel pressure / failing O2 sensors etc as per

http://www.aa1car.com/library/2000/ic60032.htm
http://www.smogtips.com/failed-high-carbon-monoxide-CO.cfm

 

[Terrorizer]

Anyone know how to test the oxygen sensors? I looked through my service manual and couldnt find it.

 

[rubydist]

since you have lean codes and the test is telling you the engine is running rich, that means the oxy sensors are bad, and are thinking that the engine is lean when it is not and are therefore adjusting the a/f mix until it is way rich.

the other issue that may contribute is if your air filter is clogged/dirty.

the dis / coil issue is also likely contributing to the CO levels being high if the spark is weak.

as I said above, replace the oxy sensor (at least the rear one) and the dis and go on with life.

 

[Terrorizer]

Does anyone know how to test O2 sensors. I wouldn't be surprised if they are bad, its just I hate spending money on parts that don't fix the problem. I have had bad luck in the past assuming a part stopped working only to find out it wasn't the problem after I replaced it.

 

[Terrorizer]

since you have lean codes and the test is telling you the engine is running rich, that means the oxy sensors are bad, and are thinking that the engine is lean when it is not and are therefore adjusting the a/f mix until it is way rich.

the other issue that may contribute is if your air filter is clogged/dirty.

the dis / coil issue is also likely contributing to the CO levels being high if the spark is weak.

as I said above, replace the oxy sensor (at least the rear one) and the dis and go on with life.

Are both oxygen sensors the same part number? Bosch 13942, from what I remember there are 2, one for each cylinder bank, right?

 

[Fordlover96]

Yes, 2 total O2 sensors. Both upstream of the convertor. And that Bosch 13942 is the correct part number, I replaced my old ones about 5k ago with the 3.2L version and everything is swell.

 

[rubydist]

the oem parts had different length wire pigtails, so were 2 different part numbers. most of the aftermarket ones have the longer pigtail, so just one number works.

 

[wjayg]

Hope it is not an atx the rear one is **** to get to

 

[Terrorizer]

No, its a manual transmission. Is it pretty straightforward? Unscrew sensors and unplug cables and replace?

 

[itwonder]

It's pretty straightforward. They are pictured in this document you can get from dropbox. You can buy a special O2 sensor socket with a slit cut in it for the cable if they are stubborn..

SHO Rod Bearing - SHO Phoenix.doc

https://www.dropbox.com/l/EeLRPOedZ8ULdnVBrTUGOo

 

[wjayg]

I have done mtx much easier than atx
Disconnect the battery
They also make a special wrench but you can do it with standard wrench to

 

[DeepPower]

See below, from another post I wrote. As I recall, pulling the SPOUT connector causes the timing to not advance which makes the engine run a little rough while reducing CO2 and NOx. Now I live in Texas where my '89 is too old for emissions inspections.

Venting the PCV to the air is a quick and easy way to reduce emissions, but be careful - it can't be obvious what you had done because in some states that may not be O.K. I now have the PCV venting as permanent.

Do the SPOUT connector as above. Also, one more important thing - vent the PCV hose from the crankcase to the air and block the vacuum hose to the manifold.

The ugly crankcase fumes are sucked into the intake manifold and dramatically hurt your emissions. Doing the above let me pass emissions in Massachusetts, which has some very harsh limits on emissions. Be aware that you MUST do this in a way that is not obvious from a visual inspection.

After doing the above, just to be sure, you should clean your intake manifold because over the years the crankcase gases and oil fumes have put an ugly coating in the intake that can also hurt your emissions.

I have this setup as permanent, and I get a small boost in HP and MPG.

 

[Terrorizer]

I replaced both the oxygen sensors today, it was a piece of cake, very straight forward. I passed the emissions test with flying colors. Thanks for the the help everyone, what would I do without SHO forum?

 

[rubydist]

we would all be even more broke than we are now...