98 F150 4.2L Code 420 Catalyst Efficiency - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

mex2texzz · 08-18-2011, 18:34

Basically my engine died after I made it home. (My 98 F150 had been flashing code 133 for a couple of days).
Here is how it started, I went to 60 mph for about half a mile then after a left turn i went down to 35mph at this point my "check engine" began to flash. I took the turn into my driveway and place the truck to Park and that's when my truck started to act out: first it felt as if it was loosing power, then there was white smoke coming out of my tailpipes, shortly after that my engine died...
I got the codes:
133 - O2 Sensor CKT Slow response (Bank1 Sensor1)
420 - Catalyst Efficiency below threshold Bank 1
301 Cylinder 1 Misfire Detected.
I have already replaced the O2 sensor but that did not fixed it. Now I am wondering if my cat is basically clogged? I have heard that at times this can be unclogged if you add lacquer thinner when your tank is half full/empty and run the vehicle. Just wondering

after I replaced the O2 sensor the engine felt as if was going to start but it only struggles for a second and then it shuts off.

Thanks for your help
Daniel
98F150 4.2 195,000miles
About two months ago I had a short on the A/C wiring and the place of the short was right at the O2 sensor, which I suspect is what got my O2 sensor messed up.

http://youtu.be/qK5Ho4nb0fM

Bluegrass · 08-19-2011, 01:02

.....The missfire cylinder one was the flashing you saw. It was passing raw gas to the cats on bank 1. If you drive long enough with this condition the front cat will melt from the high temperature of burning the raw gas (over 1000°).
.....The code 420 is the failure when the 'ratio' of switching between the front and the rear OX sensors go out of limits indicating the cats are no longer are functioning.
.....The loss of power is the cats physically melted and blocking the outlet.
.....The end results of not addressing the issue sooner will cost you for cat replacement plus the cylinder 1 missfire.
.....The loss of the cat assembly and the code 420 was only an end result not a cause.
Good luck.

mex2texzz · 08-20-2011, 11:52

Well here is the update, just took off the exhaust system and the catalytic converter is broken (the honeycomb) it made it to the secondary converter closer to the tailpipe on the passenger side. But, bit butt, is that it was what seems like antifreeze in the converter. I rotated the engine and saw more antifreeze gushed out of the exhaust manifold (the exhaust was removed) does this means my engine is history? Im planning on opening the engine and see whats up just wondering if anyone had any ideas what I should prepare myself for.

Daniel
The results video: http://youtu.be/pBufcMugYtA (aka lessons learned the hard-way)

**R.S.LOGAN** · 08-20-2011, 12:31

Head gasket gone ?

mex2texzz · 08-21-2011, 09:44

Not quite sure yet but i hope is just that and not a bent valve

Jasenford89 · 08-23-2011, 14:19

This same thing happened to my 4.6, it started hesitating, then no power what so ever, then eventually nothing. I never took a code reading but when i finally took it to a mechanic, he told me my cats were so clogged up that it burned every valve, so about 900 bucks later (with a "friend Discount") I got new valves, and gaskets put in. But i never put the cats back on.

mex2texzz · 08-31-2011, 06:34

Well after closer inspection (me and a mechanic friend) we found the following: First I took off the cats and the one with the 45 degree angle right after the exhaust exit was broken as you might have seen on the video.
Then after that we found out that the head gasket was ripped on the 1st and 6th cyl area. And of course, there was plenty of water in the engine. After a couple of starting attempts without the plugs there was a lot of water still pouring out. we reinstalled the plugs and it took about 10 starting attempts before the engine turned.
So about $500 for parts and labor later (that includes 90 for labor, two 90 some cats each, the gaskets, i replaced the valve cover gasket while there, and new plugs, and other misc tools for the job) but now is ready....kind of. I still need to weld the cats to the pipes and it should be back on the road. will post pics later.

I had no idea it was going to be this pricey, but it could have been worse!