Would blocked,partially blocked or not perfectly flowing cats, automatically trigger the check engine light ????

Reason for asking is that I'm still trying to figure out how my m.p.g could have gone from 14 m.p.g to 9-10 m.p.g in a matter of weeks. I just remembered that the reason that I had changed the aft cat O2 sensors, is that I had put acetone in my gas in order to clean the intake, injectors and the rest. But as is suppose to happen when using acetone, a lot of **** was dislodged, and burned by the cat, creating a burned eggs smell. Although I changed the O2 sensors, I was wondering if that action had also damaged the cats.

 

The first thought to me is that it is a striking possibility you melted your cats and your exhaust is backed up. I don't think the acetone would produce a negative reaction with the cat comb, but all the gunk that it got out probably went right through your exhaust valves and landed all over your honeycomb cat inerds. Excess oil on the comb will melt the cat causing blockage and failure. Has the check engine light come on at all? Anything from excess oil, coolant and even excess water coming in contact with your cat will melt it and block it. When you replaced your O2 sensors did the sensors appear oily at all? When you have your windows down and are driving around town, can you smell some really bad and unusual exhaust odors? To answer the first question you had, they can trigger the engine light. But it depends on severity ( a threshold limit of the cats). I don't know how much acetone you dumped in, but it has to be a tiny amount around 1 ounce per 10 gallons. After mentioning you used acetone, I'm thinking your cats are gone or you dissolved some rubber or o-rings in the fuel system (injectors). That's my diagnosis and I'm stickin to it!

Check out this excerpt and link.

Use as an automotive fuel additive (acetone)
Some automotive enthusiasts add acetone at around 1 part in 1000 to their fuel, following claims of improved economy. The practice is controversial as acetone may affect fuel system parts, such as rubber seals. Reports of vehicles covering 50,000 miles (80,000 km) without fault[citation needed] would suggest that the percentage 0.01% acetone to fuel ratio will not adversely affect any parts, pipes, seals etc.[citation needed]*

*excerpt from wikipedia.com http://en.wikipedia.org/wiki/Acetone

 

1 ounce per 10 galons is exactly what I used. And the site you suggested is one of the few ones I had studied before starting to use acetone in any of my vehicles. I've only used it once in the Disco, but almost every second fill up in my Jeep. I was approximately at 3/4 tank containing acetonewhen my O2 sensors went, and I filled it up immediately to dilute it even more. The old sensors were covered with a thin black film. No I do not get bad smells when driving.And the check engine light came on with the aft cat O2 sensors codes P0141 and P0161, when the sensors were replaced, the light was reset and never came back on.

One of my mechanic friends has a test he can do with an infra red thermostat that he uses at different points along the exhaust to check for blockage and other exhaust related problems.

 

Get your fault codes read and then send me your tele number, I 'll call you annd we can work thru this.
Mike
mikeljacobs@comcast.net

 

I do not have anymore fault codes. I did have the ones mentionned, but after the aft cat O2 sensors change, they were erased.

 

You should get a fault code if one of your cats has a problem, if you hit the cat with a soft hammer and it rattle like something loose inside, you have a problem.
If your only concern is the smell from your exhaust, I would be concerned as to why the cats are working so hard to make them smell, sound like an excess fuel issue.
Also I would not do the acetone thing, it can cause some problem and is not worth the risk.
Mike

 

O.k, I have no fault codes at all, the bad smell I got was only this one time after I had put the acetone in my gas , an hour before the light came on in the dash which was the result of the O2 sensors failing. Replaced the sensors, the computer was reset, and no codes have come up since. Does that mean that there's nothing wrong with my cats ??? Remember that my reason for asking is part of my quest to find the culprit in my poor fuel economy.

 

Doesthe catmake kind of a ticking or tapping noise? No codes does not necessarilly meangood cats. I know my cat is bad and my code only comes on for it couple times a month. I just hope that acetone didn't destroy your injector seals causin them to dump more fuel in. Does the exhaust look like it's running rich? Can you smell a richodor?

 

What year is your truck, how many miles on it, what gas octane are you running, what sort of tune related work has been done on your truck in the last year or so, plugs/wires etc?
Mike

 

Acetone was only in the amount of 1 once per 10 gallons for half a tank. I then filled up the tank to dilute it even more. So I doubt (hope)that this one time have damaged my injectors. My Disco is a 2000 with 52000 milesand the spark plugs were replaced 2 weeks ago to try and resolve the fuel issue. The wires are the original wires and the air filter was a K&N that was installed 1 week after I got the truck (7weeks ago) and I re-installed the OEM filter that was new, last week after reading about all your warnings concerning the use of K&N.

My questions now, is: Can it hurt to clean the MAF sensor? Can I start having issues if I clean it and it is fine? If not, where is it exactly? How do I take it out to clean it? And what product do I use? It has already been replaced once by the ex-owner.I'm planning to do the Ace and power steering fluid change this week-end, and could do this also.


thanks again