Pete L

My 86 has always just barely passed CA smog. It passed far more easily this year, I believe this is in part due to a cleaning of the catalytic converter that I based on the research papers below that I discovered in a post on another auto thread.

I do not endorse / recommend this process, simply telling the group that I did this on my 171,000 mile 86 and the car for the first time in 15 years passed CA smog easily.

1. Reactivation of an Aged Commercial Three-Way Catalyst by Oxalic and Citric Acid Washing by STAVROULA Y. CHRISTOU, HENRIK BIRGERSSON, JOSE Ä L. G. FIERRO, AND ANGELOS M. EFSTATHIOU

2. Reactivation of severely aged commercial three-way catalysts by washing with weak EDTA and oxalic acid solutions by Stavroula Y. Christou, Henrik Birgersson, Angelos M. Efstathiou

Solution / Chemicals to Clean

Oxalic and Citric Acid.
Based on the research papers the most effective solution was a mixture of 0.1 M each of oxalic acid and citric acid. I will not get into the math but ended up here. I mixed 12.5 oz of citric acid and 6 oz of Oxalic acid into 4 gallons of RO/DI water providing about .1mol with the citric acid, but only half of that concentration with the Oxalic acid.

Process:

Remove converter from car

First I purchased Oxalic Acid from Amazon

Secondly, I purchased Citric Acid, also from Amazon.

Third – I purchased at large blue tube

Forth, I purchased a pump and hoses – see photo

Fifth - I mixed into 4 gallons of distilled water that I heated beforehand to about 110 degrees the above (12.5 OZ of Citric Acid and 6 OZ of Oxalic).

Sixth - I placed the pump and converter approximately in the configuration shown in the photos (note, this is my Y pipe, not my converter) for illustration purposes.

Seventh - I ran the solution through each side of the converter 2 hours each. At the end of the process the water was a bit discolored (sort of golden green)

Eight – reinstall converter

No flames, posting for information only

polecat702

My car doesn't have cats, but what's the cost of all this stuff compared to a new converter?

Mark Anderson

Pete that sure looks like an X pipe with no cats

KenRudd

^^^^^^^^^^^^^^^This^^^^^^^^^^^

Edit: Just saw this note:
"..../note, this is my Y pipe, not my converter) ..."


Disregard and carry on.

Speedtoys

I guess it worked then...

V2Rocket

1) find long steep grade of deserted highway
2) approach bottom of grade in 4th/5th gear at 2000rpm
3) floor throttle pedal and hold it there until either you get to the top of the grade, or achieve highly extralegal speeds
4) "rinse and repeat"

my preferred "italian tuneup" spot is a 6 mile, mostly straight stretch of completely deserted old highway up in the mountains at about 5000ft.
blew all the crap out of the exhaust of my old subaru and it runs great afterwards...not enough air pressure/HP to get over 85mph and its not even that steep though

Rocinante

Please read OP's sixth item: "...(note, this is my Y pipe, not my converter) for illustration purposes."

KenRudd

Yeah I saw that , see my edit.

Carry on.

123quattro

Drive the car really hard on the way to smog station. Hope for a short line. Key off when you get there. Push the car through line. Hope for the best.

Pete L

Mark - did the process on my converter, just used the X pipe that is off the car but about to go back on for the photos

The chemicals were around $15 for each. The pump cost me $75 and I use it regularly around the hose to pump out my outdoor fountain for cleaning

Speedtoys

...so what were the pre/post test numbers?

potdog

To get car's through UK MOT emission test or when engine management light on when cat is the problem well tried and tested. Fill the cat after blocking all outlets but one with acid wheel cleaner leave 24 hrs and then pressure wash out works every time,

Speedtoys

Id just buy a new cat...I dont see acid washing a critical rare-earth component is fixing anything for long term ownership.

siscogts

Half an hour, in case of an oil burning gts.