Should I add CAT converter back to my 87

[shinkle]

The previous owner cut out the CAT converter on my 87 R10 5.7. The truck is almost 100% original with 105k miles. I get a really strong smell of fumes from the exhaust and a little in the cab when sitting still. Would adding the CAT back fix the fume smell?

Are there any sensors, ect. that I would need to replace or add back with the CAT?

Other ideas?

 

[Bextreme04]

The previous owner cut out the CAT converter on my 87 R10 5.7. The truck is almost 100% original with 105k miles. I get a really strong smell of fumes from the exhaust and a little in the cab when sitting still. Would adding the CAT back fix the fume smell?

Are there any sensors, ect. that I would need to replace or add back with the CAT?

Other ideas?

An 87 TBi setup only has a single wire O2 sensor before the CAT, so there is no difference having it installed or not.

If you are getting heavy exhaust fumes in the cab, I'd suggest looking real hard for an exhaust leak. Or maybe make sure your tailpipe is run all the way to the back.

Having the CAT will make the exhaust smell less "rich", but will not decrease the amount of exhaust. If you are getting exhaust into the cab from a leak before where the cat is installed, you will likely only make the leak worse. Modern high-flow cats will have almost no restriction to the exhaust and aren't that expensive either.

 

[Grit dog]

Truck may be running rich?
Regardless, shouldn't be getting fumes in the cab as a general course, at all.
Personally I wouldn't spend $5 or 5min adding a catalytic converter back, but it will work as intended and clean up the emissions.
I'd spend time/$ to ensure it's running perfectly first (although it may be already).

 

[82sbshortbed]

No stinking cats on mine either.

 

[RoryH19]

My 87 r10 has a cat.
Magnaflow hi flow cat and muffler.
Also have the 350 tbi.

It does help but as others mention, you seem to have an exhaust leak.

BTW, mine had the original cat when I replaced. It was the size of a briefcase. I know it was restive. Your truck probably runs better without the original.

 

[SirRobyn0]

No having cats will make your exhaust smell stronger.

I would start by making sure you don't have any exhaust leaks.

Then check for rich running, cause if it's running rich and you put a cat on it, you'll burn the cat up in short order. Make sure the thermostat is good, that it's getting up to operating temp and if it's fuel injected that the computer is going into closed loop. Make sure your timing is set right and tune up parts in good condition.

Where does the exhaust terminate? If it terminates before the rear wheels you're going to smell it at times in traffic cause it's to close to the cab. Out the sides behind the tires is better, but straight out the back under the bumper is best.

If everything is in good operating order then yes putting cats back on it will make for less exhaust smell, and it'll definitely lower NOx emissions, while NOx is odorless, it is very good at destroying lung tissue.

The type of cat @RoryH19 is talking about is a pellet type cat and they are long out of production. A high flow cat would be preferred but any universal cat will be better the factory pellet cat. Likely that is why so many people hates cats, those pellet type cats where terrible, any modern cat is light year ahead.

 

[shinkle]

The exhaust terminates behind the driver rear wheel. I don't hear any obvious tick tick leaks near the manifold. There could be one at the rear muffler weld.

It has new plugs, wires, distributor cap, thermostat. Starts and runs smooth. Just stinks to high heaven. I get a little blue smoke on start up, mostly after sitting awhile.

Not really sure how to check the computer is closed loop, I can't check timing so would need my local shop guy to do that.

 

[SirRobyn0]

The exhaust terminates behind the driver rear wheel. I don't hear any obvious tick tick leaks near the manifold. There could be one at the rear muffler weld.

It has new plugs, wires, distributor cap, thermostat. Starts and runs smooth. Just stinks to high heaven. I get a little blue smoke on start up, mostly after sitting awhile.

Not really sure how to check the computer is closed loop, I can't check timing so would need my local shop guy to do that.

If you have ever had a carb'ed vehicle without a cat and it is slinkier than that, you have a problem. Timing can really make a difference. Blue smoke if only at start up is a non-issue, if your getting the smoke at idle or the exhaust smells like burn oil that's another thing.

If you're up for dropping it at the shop you use, I'd have them check the timing and check to see that it's getting into closed loop, that has to be done with a scan tool. If all that checks out I'd move forward with the cat.

 

[Snoots]

Would adding the CAT back fix the fume smell?

NO

 

[Raider L]

If I'm not mistaken all vehicles '87 and earlier don't have to retain the converter. Just leave it off. If you really want one. Flowmaster makes an excellent one that is basically a open pipe that is straight through. I has a tube inside it that has hundreds of holes drilled in it and probably has something between the inner tube and the inner walls of the case but I can't imagine what, probably some fiberglass. It is in the shape of a small catalytic converter. It's pretty cool. I got one when I was hopping my '94 Honda EX Vtec, up. Go to Flowmaster and look for the "high performance converter". I even think Jegs has it to. That may have been where I got mine.