JmD87

Hello all, new to the forum but have used lots of info in the past and just want to first say thanks.

I have a 2002 F150, 4.2 V-6 that has a pinging problem. In recent day's Ive done two seafoam treatments, cleaned the MAF, ran diagnostics on much of the EGR system and found I might have a faulty DPFE.

Please let me know if this sounds accurate.

Put a volt meter on the DPFE Ground & SIG Terminals (Harness connected, backprobed). With a cold engine, I get a reading of 5V. However (and here's the confusing part), when I unplug the harness and check voltage on the harness itself, I'm getting the same 5V on both SIG & REF terminals.

I'm assuming this is not normal. Any clues?

Thanks to anyone who helps!

Mr B

According to my Haynes manual, the voltage is checked with ignition on (engine not running) on the harness side of the connector using the REF terminal and should fall between 4.0 and 6.0 volts. Sounds like your problem is somewhere else.

JmD87

Yes, that's the point I'm trying to make. The REF terminal, as well as the SIG (Signal) terminal, both show 5v no matter what temperature the engine. SIG terminal should fluctuate based on what temp the engine is when plugged in.

I feel like I'm not explaining this clearly. Is what I'm saying confusing?

Mr B

No, you make sense. I misunderstood. With a cold running engine there should be no egr and aprox. 0.20-0.70 vdc at the back of the dpfe sensor harness. As the operating temp rises you should approach the 4.0-6.0 vdc target voltage.

JmD87

Bump.

I replaced the DPFE with no luck, however found a new problem.

As I stated before, I'm always getting 5v to the SIG terminal (Cold or hot). I am also always getting 1.03v to the REF terminal cold or hot, and only when plugged in.

When I check the harness unplugged, both are 5V.

This is beyond me, anyone familiar with this problem?

JmD87

EVR bench tested okay

JmD87

I understand I'm basically talking to myself, but maybe one day someone will refer to this thread for their problem and will them (and also maybe someone would be kind enough to voice their opinion)

I did a running test on the EVR which consisted of hooking up a vacuum meter and testing the vacuum while driving. At idle, the vacuum FROM the EVR TO the EGR was 0mg hg (which it should be). While driving at about 2000rpm and a moderate throttle (where I get most of my pinging) the vacuum at the same place was a mere 4 mg hg. No matter what I did to the throttle, it never exceeded 4.

I hooked up the vacuum gauge to the intake supply that goes to the EVR, and I get a solid 15 at idle, and it drops to about 9 when I accelerate to the point where my pinging starts.

Can an EVR Solenoid work, but not at 100%? If I'm not mistaken the EVR Needs about 8mghg to open fully? I do not want to throw money away at parts unless I'm sure it's correct.

Weldman0730

yes solenoids are known to get stuck when they get old, sometimes they can work and other times they get themselfs stuck. I am not really familiar with your problem however.

Good old Bill

You are up on your understanding more than I, my limited knowledge is V ref is 5 volts, sig ret is the sensors value or input to computor. Thats all I think I know. Am not supposed to through out names for help, but Torkum and wde3477 where in the "H" are you this lad needs you.

JmD87

Hello everyone. I am replying to this thread because I have finally, after months & months of problems, fixed my pinging problem. I want to share my story for some poor guy in my situation, who just may have the same issues I did. This story is kind've long, but worth reading if you're desperate.

Background:

Back in 08' I had a sudden pinging problem, the sound which most closely resembled shaking a tin can with a ball bearing (or small marble ) in it.

After tons of web surfing, I did the typical checks of emissions parts (cleaned MAF, new DPFE, tested for vacuum leaks/egr problems, etc...) While I did actually have a bad DPFE (and replaced it twice because the first one was faulty!), it did not solve my pinging problem.

For the most part, I lived with the pinging for the following 1.5 years because it wasn't significant enough to make me worry, and I noticed many people say their mechanic said the ford engines are just "pingers" and to ignore it.

I never had a check engine light with all the pinging going on, which made it tough to diagnose my problem. It wasn't until recently I threw a P0174 (similiar to people who throw P0171 ) which is a running lean code. After some more web surfing I stumbled upon this website:
http://sites.google.com/site/fordf150p0171p0174fix/Home

If you're not supposed to link to other websites I apologize, it's just a great reference for people with this engine.

The link has to do with an underlying issue with ford f150's 4.2L v-6 & windstar I believe. I figured the P0174 had to do with the isolator bolt issue as described in the website, so I decided to tackle the project (which turned out to be a fun project, do not be intimidated it was not hard at all!).

While I had my intake off, I noticed my left side IMRC Butterfly valves moved freely, that is I could touch them and open/close them at my leisure. The right side wouldn't budge. Turns out one of the linkages from the motor that controls the IMRC Valves became disconnected, which made the left 3 cylinders not run correctly. I'm not fully aware of the purpose of the IMRC valves but I have a very good feeling (now with proof) that these were a) flapping around wildly making the ball bearing in a can sound, and/or b) causing a lean condition which increased cylinder temp & caused the pinging.

I went to the ford dealer and picked up a $7 plastic piece that connected the linkage to the butterfly valves, put the truck back together and took it for a test drive. I was absolutely stunned when I realized my vibration between 60-70mph that I thought was my U-Joints going bad, was actually caused by the IMRC valve linkage. I now have what feels/sounds/drives like a brand new truck, no pinging, no vibration, nothing! All because of a little $7 plastic piece.

So for anyone who owns a 4.2 V-6 and is experiencing a pinging problem, and maybe some vibration at a certain speed, a) first check out the website posted above because it's worth doing regardless if it fixes your pinging problem and b) check those linkages while you have the intake off. Again, don't be intimidated by taking off the intake. If you are a backyard mechanic, there is no reason you can't do this fix. And if nothing else, you changed out the isolator bolts & intake gaskets which more than likely will have become a problem for you in the future.

Best of luck and I hope this information becomes useful for someone as many of you helped me out and didn't even realize it.