98 windstar EGR issues, bogs down, P0401 P0301 P1780 P1408

Long story made short as possible... 1998 Windstar 3.8. Occasionally would stumble and run bad, but if you punched it, it would clear out and take off and run just fine. I found that the front banks vacuum actuator for the intake runner was bad, I put in a new one, and it ran good for a while, then started acting up again. The EGR was replaced along with the DPFE. No help whatsoever.

I removed the upper plenum, expecting to see clogged EGR ports, like I have seen on other 3.8s, but they were not... The plugs and wires have also been replaced.. I went ahead and cleaned the EGR ports and installed new gaskets. No change, it runs OK for a while then stumbles, until you stomp it, then it gets through it and runs great??

I now get codes P0301 Cyl 1 misfire, and p0401 EGR insufficient flow. Then with Key ON Engine Run test, I also get codes P1780 and P1408. What else could be causing the EGR insufficient flow problem????

ANY help immediately is greatly appreciated!!

sounds like a coil or coil pack or module. and also when you crank starter it takes alot of juice away from fuel pump. but i don't thank it's the fuel pump. sounds more like coil or coil pack like i said i never seen a cps do this but i guess it could because that's your setting the timing. but check see if you got spark from coils you could have fuel pump tested just to see..

I am pretty sure it is not a ignition problem causing the EGR flow code. I suspect the misfire cyl 1 is a by product of the EGR flow issue. Any more ideas?

when it bogs down can you smell gas?

NO, you are just driving down the road, and it kind of peters out, bogs down, then you tromp it and it runs fine?????

I got an 2001 with a similar issue. It runs like you describe, but I only get P0401. I left a trail of my investigation:

http://www.automotiveforums.com/vbulletin/showthread.php?t=915813&page=3

This should help you understand how it all works. Even though we are getting low EGR flow, I am suspicious. It is my understanding from what I have read that IF you turn off the EGR system, i.e. disconnect the vaccum connection and plug it (manifold side of the hose), then there is nothing to open the EGR valve meaning there is no recirc. With no recirc, you will be polluting more than without; however, the engine should run fine. In my case, the engine did not run fine, the problem persisted. IF you have TOO much EGR flow, then you will screw up the mixture of air to gas and the engine will bog down, choke, ping etc. This should result in a P0402 code.

Somehow, both of us need to get to the bottom of why the engine is choking with light accelleration, but then fine when you stomp on it. I have checked all over for vacuum leaks and not found one. I was thinking that if I have a leak, then the EGR valve will not open enough and give the low flow code. However, for me it could be a sensor failure. If the DPFE fails, then the PCM will think it is meauring a low flow and then tell the solenoid to open more and more until the engine chokes with the valve wide open. When I stomp on it, more air and gas are pulled in and I think it would smooth out, but not sure if that logic holds true. I tested the hose to the EGR valve and found no leaks, but I need to make sure the vent filter on the solenoid is not plugged b/c it could have plugged after doing the P0174 gasket repair as I may have left some crud loose in there and then it could have gotten caught. If the vent is plugged, the solenoid can try all it want to open, but it won't and then the EGR vale will not open when it should and I will get a P0401. It could also be true that when you stomp on it, the vacuum builds up sufficiently to overcome the plugged vent and the EGR opens ups enough to move the valve and smooth things out, but this is just speculation. I will check into this vent and see if there is anything I can do to verify it is clear. I also plan to test the output voltage from the DPFE as it should vary as you drive th vehichle (has to be warmed up and travelling). I can also test that the valve is functioning by bypassing the solenoid with full vacuum to the EGR valve while idling. The engine should run rough and/or stall out as the valve opens. If it doesn't then the valve is stuck. I can also test the DPFE output voltage with the solenoid bypassed b/c as the valve moves, the flow through the EGR tube will increase and the sensor out put should vary. If it doesn't then I know for sure the DPFE is FUBAR.

Just some thoughts I had after reading the links. Maybe someone can confirm or deny if I am out on a limb?

Last night I cleaned the vent on the solenoid, which really wasn't plugged and I tested the EGR valve (proved it works) and tested the DPFE sensor and proved that it didn't work. Replaced it and reset the CEL. Seems better, but I hate to say I fixed it until a while has passed. I will report back. Then I may post some pictures and details on what I did.

The old DPFE sensor output voltage was stuck at 1.8V. I put in a new sensor and put full vacuum to the EGR valve and the new DPFE voltage started out at 1V and began climbing. Put it all back together and tested. Seems fine for now... I think the sensor being stuck at 1.8V was too low a setting for when the system is turned on so the PCM tells the EGR valve to open more and more until the choking happens and then eventually the PCM flags the P0401 due to the reading from the DPFE.

Thanks for all of the info! All of it looks interesting and I can tell you have put a lot of time into diagnosing it. It seems to me that the DPFE is faulty just by the fact that I have done everything else it could possibly be, BUT, it is fairly new, and aftermarket, maybe it is bad???

Please post your newest near term results after a few days of driving! THANKS

Mine was the DPFE sensor. Confirmed it. In order to prove the sensor is bad, you need a DC volt meter. I removed the cowel to get at the back vacuum hoses, but it may not be necessary, if you can locate a full vacuum line near the EGR valve that is not inline with the solenoid (I never even looked to see if there was one?). Anyway, I took the full vacuum line off the storage box for the heater controls above the A/C unit. I also took the vacuum line off the solenoid on the back of the manifold (the one that leads to the EGR valve). With the engine idling, connect the full vacuum line to the EGR valve. The engine SHOULD stutter and/or stall out if the valve is working fine and not stuck. If not, you may have a stuck EGR valve in the closed position or a vacuum leak in that line to the valve. If it stalls, restart the vehicle and leave it idling (no vacuum lines connected back up again at this point, just left loose). Place the voltmeter negative lead in the battery negative (easiest thing to do), then stab the DPFE wire (not the HI or REF...sorry can't remember what it is called, but it is the voltage out to the PCM). It should give you a steady reading if you have good contact and it should be low, say 1 volt. Mine was sitting at 1.8V (this is not good, but I didn't know it yet). So now with your other hand (the one not holding the meter lead), reach over and slightly connect the vacuum again (just enough to bog the engine without stalling it) to the EGR valve. You should see the voltage climb if all is well. If the sensor is bad, the voltage will not change. Once I put a new sensor in, I repeated the test to make sure I was correct in my thinking, and I was proven correct. At idle (no vacuum to the EGR valve), the DPFE output was 1.0 volt. As I added vacuum, the voltage climbed.

Installed a new aftermarket sensor ($36 verus Ford's $140), cleared the engine codes and all is good now. Bucking is gone, no more codes displayed and there has been more than enough opportunity for the CEL to come back, so I know I got it!.

Feeling confident, I diagnosed an 01 Ford Escape today. She had a P0401 and P0402 and the vehichle was surging and bucking at about 80 km/h. I got the same results while testing her DPFE and ERG valve and I could see a carbon build up in the tube into the DPFE, so it was pretty obvious. Not surprising, the Escape has the exact same DPFE and EGR valve as the Deathstar! but it was easier to work on because there was no cowel to remove and no big manifold on top of the engine.

Good luck. I have pictures available if anyone wants more info...

If the other replys don't work some aftermarket egr's are either sold for the wrong engine or not installed with the proper washer as some cover numerous engines. Low flow can be the sensor mentioned or the opening where it is installed is plugged. Make sure all openings are cleaned and all tubing is cleaned.