Exhaust Smell. How do I know CATs are bad?

[Fischer]

Hey all Catalytic pro's. I cleaned my MAS and IAC. I still get a "Rich" smell from the exhaust. It was really bad this weekend after a steep driveway. It smells like fumes of somesort. I don't think my CATs are getting hot enough? It has not been that bad of a smell for a while.

Also where is a good place to find aftermarket CATs? What am I looking at for a nice Hi-Flow style.

Alec?? You da man with exhaust.

Thanks for the help gents and ladies.

 

[espnfreak]

Fischer, don't get one from Ford, they want 800 for theirs. But theirs is covered under something like 8 year 80k mile warranty i believe. I got mine fixed at 79k

 

[Fischer]

Argh...I just passed 80K. I have a 95 so that would still qualify in the time span. I may call them and see if they will support them.

I wouldn't mind a set of High Flow ones like Alec has.

 

[jimbo74]

a rich smell does not mean the cats are bad.... take a look at the evap canister or possibly faulty o2 sensors.... bad cats normally emit a rotten egg/sulfer smell

 

[Fischer]

Originally posted by jimabena74
a rich smell does not mean the cats are bad.... take a look at the evap canister or possibly faulty o2 sensors.... bad cats normally emit a rotten egg/sulfer smell

The O2 sensors on the exhaust I can look at and use some Carb cleaner to clean.

What is the Evap Condencer?

 

[Jason_25]

What kind of fuel mileage are you getting? It might just be time to replace the 02's.

 

[Fischer]

Originally posted by Jason_25
What kind of fuel mileage are you getting? It might just be time to replace the 02's.

I get about 14 mpg average. Better on some trips worse if I am gassing it or towing. About the same as my buddy in his 4.0 Ranger. Just a bit less mpg.

I kind of forgot that you can replace the O2 sensors. I'll try to clean them then if that does not help then I'll replace them.

It is just kind of hard as I don't really know what I do to make it smell more than other times. I think it is steep inclines then turning it off. Though sometimes when wheeling it really smells and gets in the cabin and kind of gives me a headache. No leaks in the exhaust though.

 

[DarkFox1]

rotten egg/sulfer smell? that sounds familiar, I've been getting that smell for more than a year. I only have 67k miles tho, so it can't be the cats. I agree, check into the o2 sensors, advanced auto I think it is.. gives free computer scannings... so if an O2 is bad it should throw a code. (I think), if its not an O2, then look for other things, like someone mentioned the canister, cats are expensive to replace, I'd try checking all other things 1st before I fork over the cash to replace cats

 

[Fischer]

I don't have the rotten egg smell though.

 

[Alec]

Darkfox, it can be the cats with only 67k.

Fishcer: FPR: fuel pressure regulator?

 

[Jason_25]

I'm thinking FPR as well. Fischer, your gas mileage is too low.

You may want to run a fuel pressure test.

 

[DarkFox1]

outta curiosity, would this FPR thing throw a code? and would a fault o2 sensor throw a code? I was under the assumption at one point that if a sensor was faulty, it wouldnt know it as long as the faulty readings weren't extremley unusual.. like say a sensor reading 3 instead of one wont trigger it.. but a 5 would, even tho it should be reading 1 instead of 3 or 5? does that make sense? I think my brain is broken

well, any way we can check our cats? someone told me to check with a heat sensor to see if its getting really hot, I assume fisher already did this tho since he mentioned them not getting hot enough.

I know by looking at my cats that one of them is a bright brown color, while the rest o fmy stock components are a dark brown (some sort of coating? its not rust)


I think fischer should check any and all places that match the symptoms as a possibility, perhaps its more htan 1 thing causing the problem.

btw I also get a low fuel econ.. around 9-12 city, maybe we have the same problem in this area heh

 

[zavaral]

iget the same gas millage what exactly do cats do ive heard either in texas or san antonio after your truck is over 75k you can take the cats of it this true

 

[Fischer]

Okay, how do I do a fuel pressure test? I will go through the chiltons when I get home if it is too much to explain.

List to do(?):
**Check and clean O2 sensors
**Heat sensor? I have not checked
**Check FPR

Also I live in Denver so this may have something to do with the economy of the truck.

 

[Alec]

Darkfox, the best way to check your cats is to take them off and look inside. If they look all clogged and burnt, then they are And thinking about it, bad cats could be causing your problems (most of them anyway), especially if they're really bad. The only thing is they should throw a code if they're that bad.

Fischer, I know there's a way of checking the FPR by just disconnecting the vacuum line to it and seeing if it makes a difference at idle. I forget exactly how that works though, might try searching. But a sticking FPR could definately be causing your problems.

 

[aldive]

To measure Fuel Pressure, just slip a gauge onto the fitting made for tht purpose.

 

[aldive]

ke a look at

Originally posted by DarkFox1
if an O2 is bad it should throw a code.

Not always.

I had major problems caused by an O2 sensor' take a look at Dead Link Removed

 

[Fischer]

Okay, I've done some searching and I will run and get this pressure guage with a schrader valve fitting.

Now, I am sure that Chiltons has the stats on the pressures, (haven't looked yet, boon not avail).

I saw a "squeeze" test which stops the return fuel and then the PSI from the pump should go up. So this is the fuel pump test correct?

What will I see if the FPR is bad?

 

[aldive]

The fuel pressure specs on my '99 are as follows:

Fuel Pressure 65 +/- 8 psi

 

[Alec]

If the FPR is bad (with the rich exhaust), then the pressure will always be high and won't vary much.