Insufficient EGR Flow - CEL

Ok,
I have scoured the internet, including these forums regarding my CEL. I have a 1996 Ford Windstar 3.8L with approximately 125k miles on it. The check engine light came on about a year ago and it's been a little cat and mouse chase for me, except the mouse seems to be a ghost. Here's what I have had done.

1) Had the computer read and had a misfire on cylinder #3. Mechanic checked the cylinders and found a bad injector. Replaced all injectors and had a complete tune up done on the van including pcv. $400

2) Light back on 2 days later, van running like crap with a horrible idling problem. Insufficient EGR Flow indicated on OBDII. Mechanic replaced EGR Valve. Van ran GREAT.

3) Light back on, already failed emissions for Illinois EPA team already. Insufficient EGR Flow. Replaced DPFE as per suggestions on these and other forums.

4) Light back on. Insufficient EGR Flow. Took off Plenum and cleaned EGR ports (VERY CLOGGED). Cleaned with gumout and pipecleaners as per suggestions on this site. 3 hours time, Reassembled, van runs better than ever and sounds great.

5) Light back on. Plates will be suspended due to failed emissions on Saturday, June 25th. I am at a loss for what else could possibly be done on this. The only parts I haven't replaced are the PCM and the Catalytic converters on the emission system.

Any other suggestions would be greatly appreciated on this as we don't have a vehicle to drive because of the upcoming suspension on the plates. Is it possible that it's the PCM? Should I feel draw (vacuum) on the hose that connects to the EGR Valve or from the EGR valve itself?

Thanks and desperate...

Tim

tjkashin, welcome to the forum. Sorry you're up against the wall. Maybe the exhaust gas that should be delivered to the EGR valve is low because of a clog...somewhere between cylinder exhaust valves and the EGR valve? If replacing EGR valve made it run great...maybe it was clogged? Now, new EGR valve clogged already? Maybe someone who has actually torn into this area can comment.

Replacing the PCM? Seems possible the EGR control electronics failed...I'd check everything else I could before I paid $300-400 for that part.

Is the current light a P0401 also? This code is a 2-trip code; does it always light on the 2nd trip after clearing?

I'm asking because I'm trying to gauge if this is a hard failure, or an intermittent one.

Are you still getting P030(1-6) misfire codes? If you are, you may want to gamble $60 on a new coil pack.

You will not feel a vacuum on the hose to the valve at idle. If you rev the engine really high, you might but keep in mind EGR is not delievered until a timer is reached (~2min). I actually haven't tried this, but if you do feel it, then that would confirm the EVR as good.

EDIT: If your getting no P030(1-6) codes, and a constant P0401 code, you can check the EGR Valve you disconnecting the vacuum hose and applying a vacuum pump. With no vacuum applied, the engine should idle smoothly, when you start adding vacuum with the hand pump the idle will stumble. If you keep adding vacuum it will likely stall. If you do this successfully, I'd say the valve is good.

Then assuming your DPFE is still good, the only component left is the EVR valve (converts the PCM's electronic signal to a vaccum which is applied to the valve). You may want to gamble a $parts swap$ on this them but keep in mind it could still be a wiring/vacuum hose problem.

Also, you may want to remove/clean the Idle Air Control (IAC) with some carb or throttle body cleaner it if you haven't already. Actually I'd do ths first thing if the idle is poor. It is easy - should take all of 10 minutes. It's located on the upper intake, has 1 connector on it.

PCM's rarely fail - don't swap it.

A lot of good advice from Fdunford. I was going to suggest the EVR and I see that FdunFord has already done so. So I 2nd that.

Using a Voltmeter you can measure tha electrical output of the DPFE while using a vacuum pump (or human power) to open the EGR valve. The vehicle will run rough and stall but it will prove that the EGR and DPFE are okay. You may want to ensure that there is vacuum on the hoses to the EVR and EGR when there should be. They too could be clogged or cracked (although this should introduce vacuum leak errors).

There are some variances between model years so some of what I said may not apply but I would tend to stick with the EGR system as the most likely problem and that includes the EGR, EVR, DPFE and all associated hoses and wiring.

Back to your original post:
the EGR should not affect idle unless it was stuck open. Assume it was stuck open.

The PCM sense low flow yet we think it is stuck open. This points to DPFE or clogged ports.

Catalytic converters should not give a EGR flow code so assume they are okay.

I think you are close. Keep plugging and report back. I hope something one of us has mentioned will point you in the direction.

You should have higher vacuum at idle than off-idle because you are pulling air past a restriction, the throttle plate. I would check with a vacuum gauge and see how much vacuum you are getting, then I'd check at the vacuum hose on top of the egr valve and make sure it's getting there. Before that, I'd double check to make sure the DPFE hoses got installed on the right ports, it's an easy mistake to make and can cause some real headaches. Then I'd tie into the EVR, if that's not it it's probably a wiring concern. Good luck with it and let us know what turns up.

Thanks for all your replies. So far no luck.

I had cleaned the EGR ports and had the light reset after I reassembled and took a drive. The light came back on within about 2 hours of driving around town. I haven't had an idle problem or anything. The van runs like new with no incidents. To recap, here is what has been replaced....

EGR Valve
DPFE
Complete Tune Up
PCV
Fuel Injectors


The first code was inefficient Catalyst which led to the tune up for starters.

The code was cleared and then a misfire code on cylinder 3 showed up. This led to testing the fuel injectors and actually finding that #3 was a bad injector, so those were replaced.

The code was cleared and insufficient EGR Flow showed up. This led to the EGR Valve. Had this replaced, light came on next day. Replaced DPFE and light came on again after reset. Cleaned out the EGR Ports, light came on next day.

Each time, I had the codes reset at Autozone or local Mechanic. When I cleaned the EGR Ports in the intake, I did a quick job and felt that maybe I wasn't thorough enough. I just completed cleaning them again yesterday. Went through 2 packages of pipecleaners and a can of Gumout as well. Checked all vacuum lines, all were good. Checked voltages at DPFE, all readings are within normal range. The only part I have not been able to find is the EGR Vacuum Solenoid, most parts stores have told me this is a dealer only part, Autozone is out of them at 6 different stores in a 10 mile radius from my house. I tested this part and it seems to be operating fine.

Since the cleaning yesterday, I had the codes cleared and will have to get another drive cycle completed to see what comes of it. I have also noticed since the cleaning yesterday that the accelerator pedal is very touchy. When I first take off from idle, the van feels like it wants to jump out of the gates.

I will keep you updated on the progress while I have all my fingers, toes, arms, legs and eyes crossed that the CEL doesn't return to haunt me.

Thanks again for the help...

Tim

CEL returned. I give up. The plates are suspended due to failed emissions now and we have no vehicle to drive legally. The van doesn't qualify for a waiver because they say that $450 must be spent in repairs. I have spent $1100 and have produced receipts for this and still they will not issue a waiver.

Any more suggestions?

Tim

so you cleaned the EGR ports? Some vehicles you'll need to remove the intake manifold to clean them.

Here's an easy way to check if they are clean. Get a piece of hose, stick it on the EGR valve nipple and suck. If it stalls, then they are clean. If it doesn't stall, the RPM's should drop noticeably.

The PCM is easy to check also, but you may need a vacuum gauge. Doesn't Kragen's rent stuff for free??? You hook up the vacuum gauge to the hose that connects to the EGR nipple. Drive the car. Most Fords won't engage the EGR until you get over around 10 mph, I'm not sure why, but even if you powerbrake they still won't engage the EGR. So drive it with the vacuum gauge hooked up, clamp it down with the windshield wiper, that's what I do, but make sure the hood doesn't clamp the hose too tight. If you drive it and get a vacuum signal (almost any is OK) the PCM is doing it's job. If there's no vacuum, then you may have a PCM problem (i've replaced a couple Ranger PCM's for this) or you may have an EGR vacuum solenoid problem.

Try this and keep us updated ...

Update - (I'm obsessed with fixing this now)

I bought a code reader just so I could reset the damn CEL without having to drive to Autozone, especially with suspended tags now.

I replaced the DPFE again as I found the voltage to be bad on the one that I already replaced. There was correct voltage but it would drop off completely in a cyclical pattern like a pulse. This would usually be normal except it was dropping from 4v to 0v. New one is reading correctly.

I have been doing an extensive search for the EGR Vacuum Regulator/Solenoid and have not been able to find this part available except at the dealership. I have searched online and been to several local autoparts stores to no avail. Autozone shows a wells part # and 6 stores within a 10 mile radius of my house do not have it and cannot give me an estimate of when they will have one. I will just have to wait as I have ordered one. This is the last piece I have not replaced on the vehicle.

Other than that, it runs mint. The accelerator problem I had mentioned was the spring that I must have knocked off when I removed the plenum.

Thanks again....

Tim (waiting for the CEL Demon to spawn once again)

PROBLEM SOLVED!!!!!

Got my hands on the EGR Vacuum Solenoid today and replaced it. While I was under there I decided to check the vacuum lines. I don't have a vacuum gauge, so I did it the old fashioned way and blew through them. I couldn't get air through the line from the EGR Valve to the EGR Vacuum Solenoid. I went to autozone and bought 5ft of vacuum hose and replaced it. Just got back from a test drive and no CEL after a nice 40 mile drive on the highway and in local traffic. Code Reader tells me EGR Sytstem Ready, still waiting for Catalyst Ready to come so I can take it to the test lane.

Seems that the dealer we bought it from either tried to test that line and broke the vacuum test nozzle off in it or somebody purposely shoved a nipple up in that line blocking it off.

Thanks for all your help!!!!!!