EGR Woes

[mcleodo]

EGR Woes. My 98 Taurus 3.0 pings under acceleration, but only after it has warmed up. I have searched the web for information and tried a lot of things, but none work.
I have swapped out the EGR & DPFE sensor, cleaned out all channels in intake manifold (They were not clogged with carbon), checked OBDII for codes (Negative), disconnected battery to let engine controller relearn, new plugs & wires, injector clean, higher octane gas, checked vacuum hoses.

Not much left to swap out except the Vacuum solenoid.

Since this only happens once the engine is warm, I believe it must be related to the EGR system but I can't figure out what it is.

Any advice is welcome.

Thanks

[mcleodo]

Anyone out there with a suggestion on my EGR woes.

Since this problem only happens once the car has warmed up, could the root cause be another sensor?

What sensors or conditions impact how the EGR system works. It only pings upon accelleration, not at a steady state.

Any suggestions???

[wiswind]

I have a '96 windstar with 3.8L engine....140K+ miles.... Have messed with the EGR system quite a bit..... My case was for an engine miss (which is normally how the EGR system failure shows up).

Engine temp, throttle position sensor, and EGR flow sensed by the DPFE all have input to the amount of flow commanded from the computer.....to the vacuum regulater solonoid.

To me.....the problem does not sound like EGR.....but I am not an expert.

I am wondering if you have carbon buildup......1st thing I would try is running about 3 bottles of fuel system cleaner through....(1 bottle per fillup....for 3 fillups). This will clean the injectors and intake system as well as you can get it....without taking things apart.

In my case....for engine miss.....I still had to remove the injectors....and spray carb cleaner up into the little cup over the tip.....lots of crud in there...and it came right out.....
Point being.....fuel system cleaner is not a 100% fix for crud in the fuel / air intake system.

Also....If you have a Mass Air Flow (MAF) sensor.....clean it out with a non residue cleaner....like an electrical parts cleaner.....
And verify that your air cleaner is clean....and that the air path is clear of junk.....and....that there are no vacuum leaks.
My windstar also has a temp sensor in the air path....between the MAF and the throttle body.....spray the same electrical cleaner on it to clean it.

If you have a K&N or Air Hog filter (one that you spray a special oil on)....too much oil can result in a oil film on the MAF and Temp sensors.

[mcleodo]

Since I posted this item about EGR woes I have swapped out the EGR Solenoid with no improvement, and retested all vacuum lines (for the 4th time).

I have taken the throttle body off and see no evidence of carbon buildup.

I have not cleaned the MAF sensor (Not sure if this vehicle has one) but will check.

The airfilter is clean and there does not seem to be any leaks or loose connections.

Thanks for your new tips. This is driving me crazy!

[wiswind]

I would believe that you have a MAF....just might not be exactly the same as on my windstar......
You could check www.autozone.com and follow the links to the free vehicle repair guide for your car. Vacuum leaks are a pain to trace down....and the fuel injector dirt had me going .....and I had replaced all the EGR stuff.....
Was easy once the Engine code was set.

[mcleodo]

Well, this weekend I took the whole system apart, for the second time. Cleaned the Throttlebody, took the new EGR off and inspected that it was not jammed, cleaned all ports into manifold, cleaned MAF with electronic cleaner, cleaned all electrical connections, and, still a ping under accelleration after the car has warmed up. There is no ping when the engine is cold.

Could the engine controller be the problem?

[wiswind]

As with many failures....the possibilities are endless....
I would run a fuel system cleaner through.....
I use Redline Fuel System Cleaner.....can be bought at Advance Auto parts.
Try running 3 bottles through......you may not see results right away on the first bottle.

This will clean the fuel path....and the valves and cylinders....and is a good thing to do from time to time, even if this is not your problem.

Is also much cheaper than replaceing parts.

Also, check to see if your temp is cycling up and down slightly in the normal range......which will verify correct thermostat operation.

[BigBadStang]

just a thought....
excessive carbon build up on the top of the pistons will cause an increase in detonation (pinging) that will be more prevalent when engine temp is up. seems like it could possibly also be fuel/timing related. not sure how the ECU adjusts the timing in relation to engine temp, and throttle position, but this could be something to investigate also being that it seems as though you have covered the EGR and vacuum systems.

[mcleodo]

I have been running a fuel injector/ fuel system cleaner regularly, every 3000 miles so I don't think that the injectors are fouled. Carbon build-up may be contributing but it does get a highway run each day.
I believe it is related to the EGR system because while the engine is cold, the OBDII system provides a rich burn until the vehicle warms up, and then the EGR system is activated by the ECU module. There are no symptoms until the car has warmed up. I was wondering if the ECU was not sending the right advance/retard profile.

Thanks again for your thoughts and suggestions.

[wiswind]

I have a 3.8L engine in a '96 Windstar.....so I would be over my head to suggest more that I already have......which is general information.

You could try removing the vacuum line to the EGR valve (and plug it).....and see what result you get without EGR...... This should light your check engine light for a EGR system failure......
See if you still get the pinging......

[mcleodo]

From what I uderstand about EGR functionality, disabling the EGR does not help. The exhaust gas that the EGR allows impacts the ECU in a closed loop OBDII system. So if I disconnect it the OBDII light will come on.

If I did this test, what would the results be, just so I would understand. If I disconnect and plug the Vacuum line to the EGR and the pinging stops, what does that tell me? Does that mean the EGR is bad or is it some other component?

The EGR system is complicated and I want to make sure I understand the impact to this test.

Mant thanks for all your advice.

Doug

[xtoyotacorex]

sure your valve's are adjusted right, buy a timing light and check your timing.

[hain84]

try replacing the thermostat it has more to do with proper engine function than most realize. my engine was pinging on heavy acceleration and i changed thermostat for other reasons but i noticed it took care of pinging. it was like killing two birds with one stone.