98 Windstar 3.8L-rough running at 1500 rpm

[dougand3]

110k miles on this Windstar. 2 months ago, got a check engine code of P0301 - cyl 1 misfire. Changed plugs - code gone. 1 month ago, code came back - changed spark plug wires - code gone. Code is now back. The only rough running I get is at 1500 RPM and 40 - 50 MPH and tranny is barely into 4th gear - engine super smooth at 2000 RPM in 3rd gear before the shift and super smooth at 65 MPH well after the shift. Also, I can't get it to run rough in park at any RPM.

Changing the ignition coil next seems logical but it seems weird to me that I only get a rough engine at a certain tranny load point. Also, I heard this module has 3 coil packs - 1&4, 2&5, 3&6 - so 1&4 come off same coil pack - why never a cyl 4 misfire? (This could be a crock).

I've run Lucas injector cleaner in it, changed tranny fluid/filter last week and today added Seafoam TransTune (won't know about for it for a few days)

Would you...

Go ahead and change ignition coil?
Check compression first?
Get a tranny shop to test it?

Thanks, Doug

[12Ounce]

I'm pretty sure it goes:
1 & 5
2 & 6
3 & 4

Make sure your plug wires are in that arrangement. So now the question should be, "Why no misfire on cyl #5?" Dunno.

Are you loosing any coolant? I have heard of coolant leaks being most likely into cyl #1 and cyl #4. So NOW the question should be, "Why no misfire on cyl #4?" Dunno.

Just as a test: Remove and plug the vacuum hose that goes to the EGR valve. (This will cause additional temp codes). Does the engine roughness go away?

[dougand3]

12Ounce, you are correct...1-5, 4-3, 2-6 are the companion cyls.

Coolant level seems stable.

Plugging vac hose off the EGR valve seems to have no effect on engine roughness.

I can't check codes...I run to Autozone for them.

Thanks, Doug

[dougand3]

Another thing...It seems the engine code - cyl 1 misfire returns when it is really rainy.
Should I be thinking a vac hose is cracked and sucking in moisture?
Coil module has a crack and moisture decreasing charge?
I've never chased a vacuum leak. I'll need that book - "Vacuum Leaks for Morons". Any hints would be appreciated.
Thanks, Doug

[12Ounce]

Yes, "vacuum leaks" were to be my next suggestion.

You may need to remove the wipers and cowling to do a thorough inspection. A short length of hose used as a stethoscope will help find some vacuum leaks .... as well as find some spark "leaks". You can also use it to listen to fuel injectors.

Be sure the coil pack is clean to avoid high voltage surface tracking. AutoZone will give it a ohm-meter check if you don't have a meter. There should be no ground-paths from any cable terminal.

An inspection in the dark may also reveal spark leaks. Use an atomized water spray underhood to duplicate rain wetness.

[dougand3]

Thanks, 12Oz

I'll get on it next week when I get back in town.

Also, would you remove the EGR valve and inspect/clean it?

Thanks, Doug

[12Ounce]

No. In all my miles of driving ... I'm not sure there was ever a bad EGR valve. Now, don't get me wrong... I've let a few zealous parts salepersons suck me into replacing them, only to realize later that I was just wasting money.

I would check the diaphragm of the EGR valve by using one of those plastic hand vacuum pumps. I've heard of EGR diaphragms leaking ... never had it happen myself.

In fact, you can use the hand pump while the engine is idling and see if it is functioning properly .... it is possible that they sometimes stick in an open position.

Now the EGR sensor (DPFE sensor), that's another matter.....

[wiswind]

Just one note to add. The location of the coil pack is such that.....If I was gonna remove it to do any inspection.....I would just go ahead and replace it.

I did have to remove and clean my fuel injectors to get rid of a misfire on cylinder #1. A simple squirt of carb. cleaner up inside of the "cap" on the spray end of the fuel injector cleaned it right out. I was unable to clear it out with fuel system cleaner. It is common on high mileage engines....hardest part is removing the injectors (if you gotta clean 1.....clean them ALL).

To remove the injectors.....release the fuel pressure at the release point....that is at the center front of the fuel rail. You will need to remove the upper intake manifold, and then the fuel rail. While you are in there....verify that the EGR ports are clean....as they are right there in front of you. Then remove each fuel injector, and spray some cleaner up into the "cap" over each injector.

I have a few pictures that I took of my '96 that show what things look like with the upper intake manifold removed. Your '98 will be pretty much the same as they used the same upper intake manifold from '96 through '98.

If you have never done / had this done.....it is a good thing to do. I did not have any problem with these until I was over 135K miles......needed to clean the EGR ports......then another few thousand miles......was back in there to clean the fuel injectors. Ran really great after cleaning the fuel injectors. So....hind sight.....best to do both together as you are right there.

http://community.webshots.com/album/201931518cScpNK

[dougand3]

Thanks, 12OZ and wiswind-good webshot photos.

Made some progress today...Got wipers and 2 cowls off (lotsa work to get to this engine). I found:

1. The 3 coil packs of the ignition module measure exactly the same resistance at 1.4 ohms. The Haynes lists primary resistance at 0.3 to 1.0 ohms. Now, with my cheapo multimeter, the least resistance I see with the 2 leads touching is 0.7 ohms, so I'm thinking the module is ok. Awww, now, I read to check the secondary resitance-I didn't do that. Will do later.
2. The 3 coil packs are all getting proper voltage.
3. Cleaned the grease off the ignition module.
4. Fuel injectors all click the same.
5. PCV valve hose was weak (hose from PCV valve to hard plastic tube) and collapsing while running-replaced it with HELP! hose from Advance Auto (they have better hose selection than Autozone - at least here).

It definitely runs better after the new PCV hose.

I suspect as wiswind stated, I've got a partially clogged injector on #1. Never pulled off intake plenum and fuel rail, so studying Haynes - what is the "special spring lock coupling tool" for the fuel lines?

Thanks for your advice, Doug

[CoachKarl]

Spring lock couplings are used on a windstar to connect the fuel filter, the transmission lines to the radiator, etc. It's cheap, less than 5 bucks, well worth buying. Look for the scissor type. Basically you use it by closing it around a tube, and jamming it into the coupling. These things are way faster than the old gates clamps, or the compression fitting/nut method. My question is: Where does it say you have to use it? On my 95 3.8, once I got the rail loose from the intake manifold, I didn't need it, and I managed to pull all the injectors by hand, and a pair of needle nosed pliers.

[dougand3]

Thanks, CoachKarl

My Haynes Windstar 95-98 states under Fuel Rail and Fuel Injector Assembly..."Using the special spring-lock coupling tool, disconnect the fuel feed and return lines from the fuel rail assembly."

[wiswind]

1. Cleaning Fuel injectors. I did this on my '96 and did NOT need to disconnect the fuel rail from the fuel system......so I did not need the tool.....though I have a set. I released the fuel pressure at the valve that is at the center, front, of the fuel rail. Then I released the clips on each fuel injector....keeping an upward pressure on the fuel rail...... Then each injector could be removed and cleaned. I got in a hurry and pulled a little harder.....and a few injectors came out with the fuel rail. No damage done. However, before pulling up on the fuel rail.....remove as much crud as possible from around the injectors....They go right into the head....and you do not want to get crud down in there.

2. Coil pack. More miss when wet sounds like a problem that I did not have....but have read about here. Some people have had small cracks appear in the epoxy body of the coil pack. This would not be visible without removing and cleaning the coil pack up......and....as I mentioned.....did all the work....might as well put a new part back in. You would NOT be able to measure this with your multimeter unless the arching was bad enough to build up a carbon trail. Anyhow.....the cracks are a path for the arching to happen. Leaving plugs in too long can be bad for the coil pack and wires....
As the plugs wear.....the gap becomes wider....requiring a higher voltage to spark......and that makes the high voltage parts of your ignition system more prone to arching. My rear plugs were at WAY bigger than the specified gap......and the dealer told me that they looked great on the scope check....and that they did not need replacement.
I felt that at 135K miles....was time to change out the original plugs anyway. I did not have any problems....and did not notice any difference with the new plugs....but it was money well spent.

[dougand3]

Thanks so much 12Oz, wiswind, CoachKarl....

Well, it now runs like a top - smooth startup, idle and all speed/acceleration ranges.

Problem was clogged EGR ports (just inside the air intake - just below the plastic air intake plenum) on 5 of 6 cyls.
Cyl 1 - fully open, 4 - 30% clogged, 2 & 5 - 80% clogged, 3 & 6 100% clogged.
So, the dirty EGR gases were all going back to cyl 1...running lean, decreased O2, incomplete burn.
I installed new plugs 1000 miles ago...the difference between cyl 1 plug and cyl 6 plug was amazing.
#1 plug looked fouled/carboned up whereas #6 plug looked almost new.
Cleaned out the ports with pick and shopvac.

My first experience doing this much mechanic work...and it wasn't as bad as I feared.
Only real bad place was the top of a vacuum regulator (mounted on the firewall side of the plenum)
popped off and took a while to find...sheer terror was what ford dealer would want for a new one.

As wiswind said, you can clean the fuel injectors without d/c the rail...
the input and return lines are flexible and just fold it up.

I did buy a fuel line uncoupler "scissors" tool like CoachKarl described but didn't need it for the rail.
I did need it to uncouple the front fuel filter connection (toward engine side).

Replaced 6 injector O rings...only one was bad - had a chunk pull off when I d/c it. I didn't
replace the 6 on the bottom side of the injector (2 O rings per injector) -
they all looked real good and it looked much harder to remove
them and I feared I'd damage the injector.

I didn't change the coil pack since the primary and secondary resistances were near specs.
I pulled it and cleaned it and sanded the rust off the metal ring around the bottom where it bolts to the bracket.
The newer coils don't have this ring - just epoxy on bottom - some sort of ground?
I am looking for one on ebay.

As 12Oz pointed out with the EGR valve, I didn't even bother with it.

I learned a very good lesson -
after you've cleaned the intake real shiny with a boatload of carb cleaner (toluene) on your towel -
don't throw the towel on a stool, then absentmindedly sit on it while reading the Haynes - I learned the true meaning of HOT buns.

Doug

[DRW1000]

Dougand3...............

Sometimes the desire to fix it yourself is 1/2 the battle. I find my repairs are a lot easier with people like 12ounce, Wiswind, CoachKarl (and many more) offering advice.

I am a big fan of those who solve a problem and finish off the topic with a summary of what they did to correct the problem (as you did).

I actually enjoy working on my van now.

[CoachKarl]

Congratulations! Well Done! Yes, I agree, automotive work is much simpler while you are doing it.

Philosophy follows:

Before I start on a repair, I have a "problem". But while I am attacking it, I have a "puzzle". It draws you in. Once I succeed it was a "piece of cake".

This sort of DIY stuff is dying out. I know my Dad had as many resources about how to go about fixing things in his own neighborhood, as I now do on the web. Folks just don't do automotive stuff anymore. My neighbors all think I'm nuts. On the other hand, they do ask me alot of questions about "what they should do about" their cars. Maybe I should hang a shingle?

That clean out the EGR port trick works every time. Glad you found it "easy".

Karl