Failed Aircare - need Cat advice.

[Timpanogos Slim]

huh, i must have missed that.

There are test procedures for each component of the EGR system in the '94 FSM. I imagine the '97 FSM is similar.

Did you check the filter in the EGR modulator?

 

[richmondbob]

huh, i must have missed that.

There are test procedures for each component of the EGR system in the '94 FSM. I imagine the '97 FSM is similar.

Did you check the filter in the EGR modulator?

Filter? Bloody hell, looks like I'll be working outside in the cold tonight.

 

[kerrye]

Had the EGR tested while parked by both my mechanic (twice) and Brian (86tuning) who were both able to make the vehicle stall.

Is there another test to conduct?

T in a vacuum gauge to a hose on the EGR (I use a MityVac) and monitor the vacuum levels on a drive. You should see vacuum once the engine is warmed up under certain conditions. If you don't it's not working. I wrote up a thread with a sequence of easy ways to test the the system with a MityVac a few weeks ago. I went thru the same thing with high NOx readings. It passed once I got the EGR system working. I have a thread on that whole process also.

 

[richmondbob]

T in a vacuum gauge to a hose on the EGR (I use a MityVac) and monitor the vacuum levels on a drive. You should see vacuum once the engine is warmed up under certain conditions. If you don't it's not working. I wrote up a thread with a sequence of easy ways to test the the system with a MityVac a few weeks ago. I went thru the same thing with high NOx readings. It passed once I got the EGR system working. I have a thread on that whole process also.

Do you have links to both posts? Thanks.

 

[Timpanogos Slim]

Filter? Bloody hell, looks like I'll be working outside in the cold tonight.

You just pop the lid off it and see if the foam rubber puck in there is good.

Anyone who wants to work on their own cruiser should download a pdf of the factory service manual.

http://www.offroad80s.com/page.php?p=fsm

https://forum.ih8mud.com/sale-parts/610994-40-50-60-80-series-fsm-hell-price.html

 

[richmondbob]

Filter? Bloody hell, looks like I'll be working outside in the cold tonight.

You just pop the lid off it and see if the foam rubber puck in there is good.

Anyone who wants to work on their own cruiser should download a pdf of the factory service manual.

http://www.offroad80s.com/page.php?p=fsm

https://forum.ih8mud.com/sale-parts/610994-40-50-60-80-series-fsm-hell-price.html​

Hmmm...you can tell I was making a joke, right?

Anyways, thanks for posting the links. I'd already downloaded the FSM prior to begining this thread - I'm posting for others' opinions on what they've tried with success.

 

[kerrye]

here's a link to the testing thread. The link to my original thread where I was dealing with the same problem as you, is embedded in that testing thread.

https://forum.ih8mud.com/80-series-...e-71-code-p401-high-nox-failed-emissions.html

 

[richmondbob]

here's a link to the testing thread. The link to my original thread where I was dealing with the same problem as you, is embedded in that testing thread.

https://forum.ih8mud.com/80-series-...e-71-code-p401-high-nox-failed-emissions.html

Thanks. I found your threads late last night and between them and 86tuning's replicated your ball bearing method but with a vacuum hose cap. Took for a test this morning and failed again with almost identical (albeit lower than pre-wheelingnoob's cats) NOx readings.

I've run out of time to diagnose this any further with my grace period insurance set to expire next week. I only need a little to pass so fingers crossed he finds a cheap fix.

 

[kerrye]

Thanks. I found your threads late last night and between them and 86tuning's replicated your ball bearing method but with a vacuum hose cap. Took for a test this morning and failed again with almost identical (albeit lower than pre-wheelingnoob's cats) NOx readings.

I've run out of time to diagnose this any further with my grace period insurance set to expire next week. I only need a little to pass so fingers crossed he finds a cheap fix.

Only 2 suspects left then--modulator or EGR valve. (if the passages are clear)

 

[richmondbob]

My mechanic tested all emissions' related components and determined that the cats wheelingnoob graciously gave me weren't working well enough. This was likely due to my truck being higher mileage. Also determined that my rear O2 sensor was working poorly.

So, I had two CalCats installed plus a new Denso cat-back O2 sensor and PASSED AIRCARE! Now the HC, CO and problematic NOx numbers are like those of a new car. As many have reported, new O2 sensor has led to the LC running much smoother as confirmed by my wife who hasn't driven it since before wheelingnoob's OEM used cats were swapped in.

I still may decide to swap out the pre-cat O2 sensor even though it's still running satisfactorily. If I do, I may just order two OEM O2 sensors (pre- and post-cat) or just another Denso for the pre-cat.

A special thanks to everyone for their input, 86tuning for his EGR inspection and phone advice, and wheelingnoob for the cats (I'll bring them back to you).