Multiple DTCs, erratic idle and loud pinging

[Dekeman]

Hi all,

In addition to all the excessive oil consumption I've been having in my 2000 3.8L (addressed on a separate thread), I have some serious issues with the engine. I've had an intermittent CEL, and it came back today after taking it to the coin-op car wash. The codes that it threw today are P0401 (EGR insufficient flow), P0171 (Bank 1 system too lean), P0174 (Bank 2 system too lean), P0302 (cyl 2 misfire). The counter guy was pretty helpful and suggested that the vacuum is likely messed up and I should check vacuum lines for a leak. He also said that the DPFE is a likely culprit.

Beginning yesterday, the idle chugs intermittently. It also bucks and shudders when accelerating, but only sometimes. If you gun the engine, it responds with the bucking and shuddering and has a much louder than normal pinging, but if you ease into acceleration, it does ok. It has never had very good power but it is noticeably worse now.

I purchased this van two years ago from a friend who was a Ford dealer employee, so they did all the maintenance. The mileage now is approx 172k miles. It had the isolator bolts replaced and the redesigned valve cover installed at 45k miles (TSB 03-16-1 to include the PCM reprogram). At 54k the upper intake plenum apparently cracked and had to be replaced (never heard of that one before). It does have the original metal-encased DPFE sensor (the problem units are plastic, I believe). I have been stationed overseas again for the past year so my wife has been dealing with the van herself. It's had the oil changed but little else.

I suspect that, in addition to a possible lower intake gasket leak, my PCV grommet, into which the Motorcraft PCV valve fits very loosely, is a big part of the leak. We recently had an incident with a concrete curb, and the PCV popped out and I didn't discover it for days. The valve comes right out of the grommet with no resistance, so there isn't really a seal on it at all, which makes me suspect that this is the source of at least some of the vacuum leak. I installed a PCV catch can 2 years ago; the tech suggested that my leak was there, but I've had two vans now that have run well with those installed, so I don't suspect that. All the lines and connections are snug.

I think my way forward needs to be to replace the vacuum line on the EGR valve, and replace the PCV crankcase hose, valve and valve cover grommet. I may also have to pull off the upper plenum and see if oil pools inside it on top of the isolator bolt heads, which would indicate that the iso bolts failed again. I will also replace the spark plugs and wires, since there is nothing in the records to indicate that this was ever done. Y'all may have encountered this in the past though, so tell me what you think of my solution.

Thanks!

[olopezm]

The faulty DPFE's are the metal silver ones so you might want to check that; however, I would focus on the EGR valve vacuum line and PCV grommet first.

The PCV valve should not definitely pop out just like that, so find a new grommet and replace it.

Follow the EGR vacuum line towards the back of the intake manifold. I had a problem with it and became undone. Make sure it's properly seated and preferably put a zip tie on it to prevent it from coming loose again. Other than that, make sure the EGR tube (the one that connects the EGR valve to the exhaust manifold) isn't cracked. If everything is OK I would suspect the DPFE might be at fault.

Misfire could be either the vacuum leak, clogged EGR passages (you would have to remove the upper intake to check that) or a faulty coil pack, which are also a known problem in our models. You can inspect the coil pack by removing it and looking at the back of it; if you se any cracks on it, then it's gone bad and you need to replace it. Although I recognize that a cracked coil pack would more likely cause misfires in two cylinders at once, it doesn't hurts to check.

Oscar.

[Dekeman]

Thanks Oscar. My local dealer doesn't stock ANY of the parts I need. Which is fine since I don't enjoy getting raped through my wallet. I did manage to find a Dorman version of the grommet, which is plenty tight. It seems to have smoothed out the idle, so there was a vacuum leak there, but the bucking and shuddering and pinging continue after the van has been running a while, which tells me that when the EGR system opens up, it introduces these problems. I get worse problems when the weather is wet, so it still could be a cracked coil pack, but I'm thinking that the DPFE is the likely culprit now, or at least I'm hoping its that easy. What are some indications that the DPFE is bad? The guy at the store who read my codes mentioned a Delta Pressure Feedback issue, but wasn't more specific, and the codes don't directly address the DPFE.

I still need to change the plugs and wires, so I'll pick those up. I think I'll be opening up the upper intake plenum and checking the isolator bolt heads and EGR ports in the lower intake when I pull the cowling to check the back of the EGR vacuum tube to manifold connection. Do those isolator bolts go bad once they're replaced? Anyway, thanks again for your help and I'll repost later when more is apparent.

Originally Posted by olopezm

The faulty DPFE's are the metal silver ones so you might want to check that; however, I would focus on the EGR valve vacuum line and PCV grommet first.

The PCV valve should not definitely pop out just like that, so find a new grommet and replace it.

Follow the EGR vacuum line towards the back of the intake manifold. I had a problem with it and became undone. Make sure it's properly seated and preferably put a zip tie on it to prevent it from coming loose again. Other than that, make sure the EGR tube (the one that connects the EGR valve to the exhaust manifold) isn't cracked. If everything is OK I would suspect the DPFE might be at fault.

Misfire could be either the vacuum leak, clogged EGR passages (you would have to remove the upper intake to check that) or a faulty coil pack, which are also a known problem in our models. You can inspect the coil pack by removing it and looking at the back of it; if you se any cracks on it, then it's gone bad and you need to replace it. Although I recognize that a cracked coil pack would more likely cause misfires in two cylinders at once, it doesn't hurts to check.

Oscar.

[olopezm]

Since DPFE sensors are faulty enough to cause issues but not enough to trigger a DPFE related code all you'll get are EGR related DTC's. Misfiring could be one of them as DPFE is reading incorrect data and commanding the PCM to open the EGR valve; that would surely cause a rough idle too.

You could try feeling the vacuum line on top of the EGR valve to see if it has excessive vacuum, if it does then you've found the problem and DPFE is the most likely culprit. A small amount of vacuum is acceptable at idle.

I'm thinking you could just unplug the DPFE sensor, start the engine and take the van for a drive. The PCM should compensate (up to some point) for the lack of input and drivability problems should diminish or go away if that's your problem. Be advised that disabling the EGR system for a long time can increase temperature in the combustion chambers and elevate NOx readings so, use this information only as a diagnostic method rather than a solution .

There is a procedure in which you can pull vacuum on the DPFE REF hose and backprobe the connector in order to read the voltage readings, the only problem is that you can actually damage the sensor by pulling too much vacuum or creating excessive pressure. I'll see if I can find it for you if you want it.

I have no idea if the revised isolator bolts can go bad, but having a look at them wouldn't hurt. Maybe someone else knows a definite answer to this.

Oscar.

[scubacat]

Pop in a new DPFE sensor. They're only 20 bucks or so from rock auto. They ALL go bad after 60-100k miles or so; not just the old metal ones.

[olopezm]

Originally Posted by scubacat

Pop in a new DPFE sensor. They're only 20 bucks or so from rock auto. They ALL go bad after 60-100k miles or so; not just the old metal ones.

I was thinking about it and would just follow his advice and replace it I don't like anymore throwing parts at anything but I remember that the metal DPFE sensor on my Town Car tested fine and I kept chasing a stumbling problem for a long time only to find out that the sensor had always been the original cause of it; after replacing it with one from autozone the problem instantly went away.

Oscar.

[Dekeman]

Thanks for the additional good info guys. I'd try pulling the power harness on the DPFE, but when my wife drove it this morning, it started hesitating badly, would strongly resist acceleration and the CEL was flashing. She immediately limped it home and when I looked up the CEL, I found out that it's a multiple misfire, which could be clogged EGR ports or a clogged catalytic converter. I could try to pull the DPFE harness and drive it to see if the symptoms clear up (keeping in mind that it's a temporary solution that only serves to diagnose the DPFE), but should I clear the codes before I do that?

[scubacat]

Originally Posted by olopezm

I was thinking about it and would just follow his advice and replace it I don't like anymore throwing parts at anything but I remember that the metal DPFE sensor on my Town Car tested fine and I kept chasing a stumbling problem for a long time only to find out that the sensor had always been the original cause of it; after replacing it with one from autozone the problem instantly went away.

Oscar.

I agree but anything that is a wear item (by nature or questionable design) I'll typically replace to avoid future issues. When I did the lower intake gasket, I replaced the coolant bypass hose even though it looked perfectly fine and wasn't leaking. It could have been $30 wasted, but the thought of repeating 75% of that job just to do the hose (or worse, the hose springing a leak during a road trip) was much, much worse. For $30, I never have to worry about that again. Plus it's twice as expensive if I had to buy one from a dealer in an emergency.

EVEN IF replacing the DPFE sensor doesn't solve the problem, it's still not a waste IMHO.

[scubacat]

Originally Posted by Dekeman

Thanks for the additional good info guys. I'd try pulling the power harness on the DPFE, but when my wife drove it this morning, it started hesitating badly, would strongly resist acceleration and the CEL was flashing. She immediately limped it home and when I looked up the CEL, I found out that it's a multiple misfire, which could be clogged EGR ports or a clogged catalytic converter. I could try to pull the DPFE harness and drive it to see if the symptoms clear up (keeping in mind that it's a temporary solution that only serves to diagnose the DPFE), but should I clear the codes before I do that?

Remember, a failing DPFE sensor can exhibit strange symptoms. I'd REALLY just put in a new one and see what happens before pulling your hair out over this.

[scubacat]

Originally Posted by Dekeman

Thanks for the additional good info guys. I'd try pulling the power harness on the DPFE, but when my wife drove it this morning, it started hesitating badly, would strongly resist acceleration and the CEL was flashing. She immediately limped it home and when I looked up the CEL, I found out that it's a multiple misfire, which could be clogged EGR ports or a clogged catalytic converter. I could try to pull the DPFE harness and drive it to see if the symptoms clear up (keeping in mind that it's a temporary solution that only serves to diagnose the DPFE), but should I clear the codes before I do that?

Forgot to mention - inspect and put in a new coil pack as well. That's the other piece that fails and causes weird symptoms. Everyone with a Windstar ends up with the cracked coil pack misfire issue at some point.

[olopezm]

Originally Posted by scubacat

I agree but anything that is a wear item (by nature or questionable design) I'll typically replace to avoid future issues. When I did the lower intake gasket, I replaced the coolant bypass hose even though it looked perfectly fine and wasn't leaking. It could have been $30 wasted, but the thought of repeating 75% of that job just to do the hose (or worse, the hose springing a leak during a road trip) was much, much worse. For $30, I never have to worry about that again. Plus it's twice as expensive if I had to buy one from a dealer in an emergency.

EVEN IF replacing the DPFE sensor doesn't solve the problem, it's still not a waste IMHO.

I don't have enough experience to know if they all fail or not . All my knowledge I got it from this and other great forums (thanks to all of you guys), google and some books; and I'm thankful for all that; it's been around 2-3 years since then and I'm not looking back! Now I'm 25 y/o and feel confident when working on these beasts .

Originally Posted by scubacat

Remember, a failing DPFE sensor can exhibit strange symptoms. I'd REALLY just put in a new one and see what happens before pulling your hair out over this.

I agree once more; if you can afford it, just replace it and be done with it. Luckily the DPFE's on our windstars are easily accesible unlike my Lincoln in which you have such a tight space that you ought to remove the cowling just to remove the only bolt holding the sensor in place.

And Dekeman, for your question, yes I would clear all codes and test drive with the DPFE unplugged.

Oscar.

[Dekeman]

PARTIALLY SOLVED: Once the urge to pound the van into a little metal cube with a sledge hammer passed, I replaced the DPFE and the vacuum lines that connect it to the EGR tube. The problem is now sort of reversed. Where before it would buck, shudder and resist when the engine was accelerated quickly, it now shudders slightly and resists just a little bit when it is eased into acceleration. I drove it locally and let it get up to operating temperature so the EGR system would kick in so I could tell if was going to produce another CEL. When I got no code, I took it to the interstate and was able to get it to 80 MPH without issue (besides the shuddering on easy acceleration). If I hit the gas enough to downshift, it accelerates fine, but if I'm at speed and want to accelerate just a little without downshifting, that's when it shudders and resists, but not as much as before. Could this still be clogged EGR ports? I feel like there's one more step I'm missing to get this thing running right again (besides driving it into the river).

Thanks again for all the help everyone.

[scubacat]

Check that coil pack too. That's the other tricky-to-diagnose thing that often plagues windstar owners. I'd even swap it for a new one from autozone and see if the problem goes away. If not, just swap back and return it. Even the slightest crack that you can't even see can cause misfires, etc.

Cleaning EGR ports is never a bad idea either.

[olopezm]

Oh Dekeman I know that feeling, trust me!

As said above, check the coil pack, that's the other thing in these models that will very likely fail sooner or later. Since you'll be removing the cowl to take a look I would make sure the EGR ports are OK, it shouldn't take much and will rule that out for sure. Also make sure the rest of the vacuum lines at the back of the manifold are OK.

I don't know, I might be wrong but have you checked the IMRC bushings to make sure they are OK and the linkages are properly attached? The IMRC actuator is the black box close to the alternator with two metallic linkages; with time the bushings holding them break and the linkages fall on the engine or the road. I know those can cause sluggish acceleration but have no idea if they could cause your current problem. I'm sure somebody else will comment about it.

Oscar.

[Dekeman]

Hi Oscar,

Thanks for the additional info. I ordered a Ford coil pack, Autolite double-platinum plugs (no Motorcrap available) and Motorcrap wire set from Rock Auto tonight. I've scheduled it at a highly-rated local garage to replace either the lower intake gasket or valve stem seals, whatever the h$!! it is causing the van to inhale oil, and install the coil pack plugs and wires at the same time. I've had it.

Yes, the IMRC linkages. Well, mine ended up being found by a counter tech at Auto Zone sitting on top of the block. At least the s-shaped one. The other one is missing and I can't find them to buy anywhere. I may just buy the Dorman clips and install the one I have since I've been hanging on to it for nearly two years since it was discovered. I know it's causing knocking and acceleration issues, and has been for years. The past year being away from my family (and van) has not helped our situation, and there is a lot to do to get this thing running better. I usually opt to do everything myself but I am at the end of my rope and am hiring a local shop that I'm hoping is at least semi-competent. They have many top-notch online reviews, which I realize could be BS. Even if they suck at least I won't have to do it. Just shoot me. Or my van. Or both. Please.

Originally Posted by olopezm

Oh Dekeman I know that feeling, trust me!

As said above, check the coil pack, that's the other thing in these models that will very likely fail sooner or later. Since you'll be removing the cowl to take a look I would make sure the EGR ports are OK, it shouldn't take much and will rule that out for sure. Also make sure the rest of the vacuum lines at the back of the manifold are OK.

I don't know, I might be wrong but have you checked the IMRC bushings to make sure they are OK and the linkages are properly attached? The IMRC actuator is the black box close to the alternator with two metallic linkages; with time the bushings holding them break and the linkages fall on the engine or the road. I know those can cause sluggish acceleration but have no idea if they could cause your current problem. I'm sure somebody else will comment about it.

Oscar.