What's ruining my DPFE sensor?

engines
smoke
mercury
sable
noises

#1

I made a post before about a hissing sound and smoking and a burning smell and I’ve found the culprit. I found my DPFE sensor popped off the two valves it was connected to and smoking the thing was piping hot. the sensor wasnt too melted but it was definitely damaged. the rubber hoses that connect to the valves were split and really solid and crumbling. I bought a new DPFE sensor and tried to get new hoses but the auto zone didnt carry any OEM but he found some the were “designed for exhaust” well I used them and for about 4 miles it wasnt hissing, until i heard something fall and the hissing was back. I look at it again to find the hoses in worse condition than the original hoses were and idk how long the originals where like that as it was a resent issue. they were melted and hardend and piping hot. I had to claw the pieces off cause it wouldnt pull.the new sensor melted a tad but i dont think it’s broken. Now I know I answered my question but my real question is why is the exhaust running so hot to melt? and why are the hoses and the sensor popping off? is it because I used cheap hoses? the originals seemed more thick and well suited for that sort of heat but that was HOT. is there a larger underlying problem? this car has broken down a lot and anything expensive I cant afford anymore.


#2

What year?

Tester


#3

A restriction in the exhaust system can damage EGR sensors, how is the engine performance? Check the catalytic converter.


#4

It’s a 2000 Sorry, meant to include that earlier


#5

There is likely a restriction in the exhaust system.


#6

the performance is OK at best, it stalls a lot and sputters but after driving a bit it smooths out. you can feel a bit of shaking when driving down the road but it’s more of a vibrating feeling. The engine loses power only when idle on a cold start, the RPM is inconsistent and sometimes drops below 500 rpm but when warmed up the rpm is at a consistent 1000 rpm ish. the car never overheats and responds well when I apply breaks or when I accelerate.

I only have basic level knowledge of cars and youtube videos for knowledge so im a bit limited. do i have to take them off or do I check the catalytic body itself?


#7

How would I locate/test it? is it expensive to clear it out? this is the only means of transport I have at the moment and it would ease my mind to know that this is a relatively simple fix, especially if it’s DIY


#8

Try replacing EGR tube.

https://www.rockauto.com/en/moreinfo.php?pk=3936351&cc=1364037&jsn=384

If the orifice in the EGR tube becomes restricted, the exhaust gasses can be forced thru the DPFE valve.

The valve is designed to measure pressure differential and not flow.

And the valve/hoses melt.

Tester


#9

There is a restriction to give the DPFE sensor an input into the operation of the EGR valve’s operation

http://tomco-inc.com/Tech_Tips/ttt36.pdf

gaining access to the port and running a wire through it to clear carbon may eliminate the problem.


#10

The DPFE part is involved with controlling the EGR valve I think. There’s been a few posts here before about it failing, not an uncommon thing, you might want to try the CT forum search feature to see if you can find them. Due to the heat of exhaust gas, that part has to be installed correctly, with heat tolerant accouterments (hoses, etc). In other words, don’t try to mickey mouse the DPFE. Ford dealership will have or be able to order the parts you need.

While there you can ask what problem might account for its rapid failure in your vehicle. My guess is your EGR valve is faulty and that is what is taking out your DPFE too. But that’s just a guess, and the other advice offered above should be considered too, especially pay attention to the function & integrity of the whole exhaust system, including the exhaust manifold, cat, muffler, and all the piping.


#11

Thank you. Would a bad tube cause a sucking sound as well? when I put the DPFE sensor on, it did stop that sound but when I put my ear next to the EGR valve itself I hear a very audible “SSSSSSSSSSS” sound but I cant hear it inside the car with the hood down like I did before i fixed a red looking tube that was disconnected near the EGR valve


#12

You test for an exhaust restriction with a vacuum gage. There are numerous videos on the internet that describe the process, so for the sake of brevity I’ll simply suggest you look them up.

Unfortunately, you cannot. A clogged converter means the honeycomb ceramic substrate on the surface of which resides the catalyst has crumbled. The only fix is a new converter.

Unfortunately, I’ve had problems with Autozone aftermarket parts. They have the cheapest prices, but it’s because they carry junk. I won’t shop there anymore except for bulbs or something generic like that.

If you’re willing to spend the time and effort, it can all be DIY. It does not require disassembling the engine or drivetrain. Assume that you’ll have to cut the flange bolts on the cat converter and replace them. You’ll never get 17 year old exhaust bolts & nuts apart. They’re subjected regularly to high heat and extremely corrosive conditions.

But first, read the suggested test procedures, get or borrow a vacuum gage kit and some GOOD jackstands (safety is an absolute must) and test the system to confirm that it’s a plugged exhaust. I’d hate to see anyone go through all the work of replacing a converter only to find out the cause is something else.
Diagnose first, then repair.


#13

Most EGR valves use a vacuum signal to control when it opens and how much. If the EGR diaphragm leaks, it can create a hissing sound. Or the vacuum hose going to the EGR valve can leak, same result. Mechanics have a hand operated vacuum pump they use to test for that.


#14

Aw man, I was hoping I didnt hear that. For a new catalytic converter, I may as well invest in a new used car. I’ve put too much money into this car in such little time recently. I want to fix it but something else immediately goes wrong even when a mechanic checks it for the clear. I got the car for $500 and its been kicking for 6 years so i should be grateful. I’ll definitely do the tests procedures first before jumping to conclusions. Thank you for the advice.


#15

I had a previous mechanic check and tell me that the EGR isnt responding and that it’s always “Open” he replaced it, but I dont think it fixed anything, my old EGR never did this. I honestly do think my EGR valve or something around it is causing the issue. I’m like 70% certain it’s a vacuum related issue or a non responding tube or line in or around the valve causing this. my car has always had problems involving vacuum systems. would a PCV hose affect this? my car has a lot of symptoms seen in videos that show what a bad PCV hose can cause. I’d look at it myself but the 2000 has it placed really weird


#16

Yes, the pcv system can cause hissing sounds. Any shop should be able to diagnose the pcv system for you in short order. If you feel lucky, just replace the pcv valve. I fixed a drivability problem on my truck that way a year or two ago. I didn’t replace the valve, I cleaned it, but same idea. You need to have the pcv system working correctly in any event, otherwise you’re be blowing seals and gaskets right and left. Since it is usually easy to diagnose and repair good place to start. EGR valves are a constant problem on my Ford truck. I’ve had to replace EGR valves quite a few times over the years, and clean the passages. I replaced the EGR valve on my truck just last winter matter of fact. It cost a pretty penny too, over $100 just for the part. EGR work is a common repair project for diy’ers, in my experience needed more often for carb’ed engines that fuel injection for some reason.


#17

The egr system consists of the valve, a solenoid (which may be vacuum or electronic) to control the valve, and the orifice in the throttle body through which the exhaust gasses are drawn by the engine. All three have to be clean and operating for the system to work. Oh, and the hoses have to be in good shape. You didn’t clarify exactly what’s already been changed, but you may have one of them still malfunctioning.

PCV hose is dirt-cheap to change. It’s worth trying.


#18

My 2000 mercury sable ended up doing the exact same thing. In my class it was a clogged catalytic converter. It’s the rear one which is also a manifold converter. It does take some degree of mechanical skill to replace. You can get the part off rock auto for a couple hundred. However I took mine to a muffler shop to have them install it. I was being lazy. They did a piss poor job of installation and I had to go behind them to plug in all my sensors anyway. So just be careful who you trust with the work.