'94 FZJ80 Failed Emissions (1 Viewer)

[landtoy80]

I wonder what is the default setting for the air/fuel mixture is (rich or lean) when the O2's are unplugged? I have black soot lining the tailpipe.

I do use a bit of oil but no oil smoke that I can see driving down road. I do have startup smoke but I can mask it if I use Motor Oil Saver and MoS2 10w40 motor oil. The MoS2 10w40 and Motor Oil Saver oil treatment makes the oil a tad to thick for winter use so I use my default oil Rotella T6 with Motor Oil Saver and the startup smoke is very minimal.

 

[Brentbba]

If you've ordered one, make sure which one and order the other one. The molex connectors and length of the wires are different for the two sensors! The inside one is a little more of a pain to get to, but very doable. Given that you are in CO, hit the nuts with some WD40 or similar a few days before attempting to remove them.

 

[Kungpaodog]

So the final rundown:

Replaced O2 sensors, did not clean the EGR system, filled up with high octane gas, left OD off, turned ECT (PWR) on, got the Cruiser good and hot with a ten mile loop, and passed emmisions!

The NOX was 3, limit was 4. Two years ago I barely passed wth a 3.9.

 

[landtoy80]

<<<overdrive off, ETC on>>>

This would say that higher rpm's would help when taking Colorado emissions test.
I would assume that higher prm's would = more emissions but maybe higher rpm's get the cats hotter so the cat can do its job.

 

[SmokingRocks]

Reviving this thread...

So I bought another 80 as some of you know its a 93 with 225,000 on the clock and I am the second owner! I took it to emissions to baseline it and passed everything except NOx (I was almost twice the limit). So I replaced the spark plugs (the ones in there were worn to over double the spec'd gap, really shocked the truck even ran). I added some guaranteed to pass to a fresh tank and ran it hard, sea-foamed the intake, changed the oil and replaced the way to dirty air filter.

I ran through that whole tank of gas then refilled drove to work (30 miles) then went right over to emissions and retested today. My NOx dropped to 3.3! So that passed (4 is the limit) but now my CO2 is at 27.5 limit is 25 so I failed again!

I'm going to pull out the O2 sensors and test them, does anyone know what voltage they are suppose to put out? 1 volt like most or is it funky?

Oh and here is another note, my first test I left the Over Drive off, second test I let it shift normally (Over drive on). Should I really keep the OD off?

 

[Heckraiser]

New cats was the only solution for me. I tried a handful of maintenance items and "emissons tricks," but at 300k, the cats were shot. Two new cats and it was sqeaky clean.

 

[SmokingRocks]

PO was chasing this issue before they sold it and had new cats welded in.

 

[SmokingRocks]

So this is interesting.
First Test OVER DRIVE OFF

• HC GPM 0.1846 Limits: 2.5 PASS
• CO GPM 4.5754 Limits: 25 PASS
• CO2 GPM 775.6
• NOx GPM 6.7669 Limits: 4.5 FAIL

Second Test OVER DRIVE ON

• HC GPM 0.7225 Limits: 2.5 PASS
• CO GPM 27.5025 Limits: 25 FAIL
• CO2 GPM 739.6
• NOx GPM 3.3563 Limits: 4.5 PASS

Between 1st and 2nd test;

1. Changed oil
2. changed WAY worn out spark plugs
3. replaced WAY dirt air filter
4. ran a bottle of Guaranteed to Pass through one tank

Also I think the cat was much warmer for the second test. Can anyone help diagnose these readings?

 

[AMMO]

Sorry can't help but curious what this can of "guaranteed to pass" is?

A fuel additive?

-A

 

[landtoy80]

Things that helped me pass CO emissions:
Make sure all tires are at max air pressure. (one tire was at 25 lbs, fail test)
Check the O2 plugs for corrosion. (I had corrosion, failed test)
Tune up. Clean filter and new oil.
Set timing factory setting.
I removed and cleaned the cats and O2's with oxalic acid and citric acid.
Used low emission oil, G-Oil vegy oil with 2 bottles of Motor Oil Saver additive.
Cat Cleaning Citric & Oxalic Acid. CO Emissions

Not sure which of all the things that I did lowered emissions but something got it to pass and it
has the original cats on it (400,000+ miles).

One thing I have noticed this year:
When i do mostly city driving I get the CEL 25 26.
When I drive a mix of city and hwy the CEL comes on then goes away.
After diving on interstate at 75 mph for a couple tanks of gas, the light turned off. (drove 700 mi hwy)
All summer i only made short 1 to 5 mi trips and CEL came on again and stayed on.
I drove non stop on interstate again (700 mi hwy) and CEL is off now.
I am using Rotella T6 oil that has higher amounts of ZDDP than car oil and I do have start up smoke.
Not sure if the oil is coating the O2 during city driving and on hwy driving it gets burned off???