Oil Issues so want to remove Cats!

Guys.. Forum Newbee here..

I have an extra 1999 Ford Expedition 4x4 that has been put to pasture because of a tiny oil leak behind the pass head. It drips on the cat and causes the dreaded white smoke only occasionally. Wife ejected it.

SOO.. being the low buck ride replaced out with a *ahem* new 4x4 Expedition.. I'm going to do some hacks on it to reduce the existing smoke because the engine/vehicle runs fine otherwise.

I want to delete all the cats.. so it can remove the main burning offender. Then possibly shield the pipe on that pass bottom side.. wrap it.. whatever it takes to reduce the heat, oil burning etc . I don't care if the truck leaks oil... as long as it doesn't puff the smoke. Get my idea?

So the gist is.. Remove the Cats. Replace with straight pipe.. and I need some MIL eliminators. Or do i? It already has a code up on the dash "service engine" ( probably O2 coated in oil already ) etc.. so will the o2 sensors actually cause problems with mileage, performance or will it just throw a code? If just a code.. I could care less.. hence the low buck mods here.

If It will cause issues in performance/mileage then I will just buy the MIL Eliminators and install them.

So douse me with your expanded Expedition knowledge gurus.
I'm ready to start hacking..

I removed my rear cats and i didnt get a check engine light, its alot louder, and i can tell a little difference in the performance at highway speeds. I think i might have lost a little low end torque though. Now if you remove the cats and have some pipe welded in place of it, wouldnt the oil just drip down onto the pipe and cause the same problem you have now?

It's possible.. but the burn footprint will be smaller and my goal was to possibly sheath it with a larger pipe creating an air gap so again it doesn't get hot enough to burn.

With the cat removed I can try several low cost patches with the extra gained room.

All my older cars drip something.. I just want to keep this from landing on something super hot

The information I'm getting from other sources is that if I don't use the MIL Elminators.. it will not only throw a code.. but cause it run rougher and use more gas thus impacting my MPG.

Verified or not?

If so any source for Mil Eliminators for my 99 4.6?

Going off my knowledge of OBDII vehicles as a whole, I think you have to have the cats between the front and rear O2 sensors because the ECU actually reads off the two sets and makes judgment calls for the engine with the information it gets. You can always put in some high flow cats, but you will probably get codes because they actually flow "too fast", which is where the Mil Eliminators come in. They are basically just bungs that you weld on your exhaust piping that bring your rear O2 sensors out a bit so it seems like stock flow characteristics.

Unless you're talking about something else. Like I said this is just from what I know as general info, could be different for these trucks. I know for my VDub eliminating the cat without a stand-alone engine tuner is a no-no, but high flow cat with the new bungs is all good.

Thanks. I think this is a good thread to draw a diagram. If I get the time I will..

Bummer still no clear answer on this. I guess.. I'll just have to drop it and see what the crap it does, eh?

removing one set of cats will not throw a code.

I thought removing cats was illegal. Is it legal to remove the back 2 and leave the front 2 on?

jayhawk2014 said:

I thought removing cats was illegal. Is it legal to remove the back 2 and leave the front 2 on?

Click to expand...

It is different state to state. Here in Michigan, my exhaust setup is completely legal. But if I go 30miles south into Ohio, no cats is a big no no.

OP, why not just fix the oil leak?