Help! I got a doozie of a prob here. I have an 02 f 150 w 4.2 v6. I started having probs when the ethanol content went up in gas. I would get some bad gas every once in a while and my engine would misfire and run bad until I would get it cleared up (changing fuel filters, putting stabalizer in the fuel). My truck would start throwing codes that it was running lean along with a misfire code when it was running rough. this has been an ongoing battle while finding gas that would run well. About two weeks ago, my probs compounded. My dpfe sensor melted on the way home from a 2 hr trip. I replaced it and drove about 10 miles when the new one melted. I checked the codes and it showed an egr issue, running too rich as well as lean. I changed out the egr valve with no effect and then moved to the solenoid. replaced it at well as the pigtail to the dpfe which melted. What I know is that the egr valve is letting way too much exhaust back through and melting the dpfe. Now it is showing that my engine is running closed loop the actual trouble codes now are p1401, p1131, and p1151. I cleaned the maf, replaced about all of the egr system and it is still blowing the dpfe off the rail when I rev the engine. I am tired and broke from replacing sensors and am stumped. any pros out there that can help?

 

Ethanol has nothing to do with these problems.

Among other things, you probably have a clogged cat or exhaust, most likely, from running with a misfire.

 

if it was a clogged cat or exhaust would there not be a considerable decrease in power

 

Since UR burning stuff up like crazy, disconnect the exhaust/cat and see if it runs better after U fix the burnt up stuff again. UR to the point a sawsall saved money in the long run scheme of things. The muffler guy will weld it back together for $20 if necessary ur wrong about it. A Vee cut into the pipe it will let enough exhaust escape to prove it.

 

DPFE sensors and hoses blow off because of too much exhaust back pressure. What do you thing causes that condition?

 

Easy to confirm, put a vacuum gauge on it.

 

You might possably have 2 problems.
One an air leak or low fuel pressure and an issue with the exhaust.
The DPFE is piped accross an .040" orface inside the metal pipe.
If that orface is burned/blown out the DPFE gets excessive hot exhaust gases and higher pressures all the time.
If there is excessive back pressure it may result in the same type condition.
The DPFE has electronics in it along with pressure sensors.
Since the PCM has not set a code 420, the cats may still be working well enough.
Have you looked at the possibility of a blocked muffler or tail pipe?.
Next the lean indicators are for both banks.
You may have an air leak in the intake tract at some point.
Two issues at the same time sometimes creates confusion.
I don't know what you have but the codes do suggest what you should investigate.
Good luck.

 

Since he upstream O2 codes, the catalyst efficiency tests won't run, therefore, no P0420/P0430 codes.

 

Point well taken.
It depends on when and the timing seqence of the events.
He may well end up with that code after repairing for the lean codes.
This is what I mean about more than one problem at the same time.
I believe he would have to repair the first issue, clear the codes to allow the cat monitors to run again and see what the system thinks about the cats condition.
Thanks.

 

wow, thanks guys. I know that it had nothing to do with the ethanol. I was just trying to give info from the beginning. I have gotten way too dependent on my computer and have not been looking at the mechanics of what is going on with my truck. Thank you for jarring my head a little. I have found a valve cover leak, it is not bad, but I bet it is enough to play with the koolaid. Second, I put a thermometer on my exhaust. it looks like my passenger side cat is fine. Driverside seems to be malfunctioning, that is, if it is true about the temps on the exhaust in that if you put a thermometer on the exhaustjust before and just after the cat, there should be a slight increase in temp after the cat in normal operation (50-100*)
Drivers side is running way too hot and the temp drops considerably after the cat. (got a noncontact infrared thermometer for christmas) Had a couple of people suggest this. Does it sound plausable and do yall think the valve cover leak would be the prob on the front side? by the way, I played a little with the egr and am now getting, along with the stored codes of 1131, 1151, the 171 and 174 codes popped up again. 122 code popped up, but I am sure that code came up because I checked the connection as it was running and inadvertantly unplugged the connector from the tps. I am gonna clear the codes and relook tomorrow after I replace the valve cover gaskets. I live in the sticks so I got to drive 30 miles just to get the gaskets! lol

 

I'm going with some of the other guys . You have a plugged cat. Cross over pipe can relive some but not all . If you melted and blew A dpfe you got a restriction . If you are running lean , you can melt a cat , if you are missfiring you can melt a cat . 171 and 174 are lean codes . Ck base fuel ,spark ,injection . And fix exaust after fixing other problems .