98 Windstar P0304 Other Problem?

[Ulsterman]

I found this forum a few days ago - good to see a few survivors from cartrackers, any sign of Shadetree who helped me out before?
I've had a 1998 3.8 windstar for just over a year. It's at 85,000 miles and been losing a little coolant for some time until I recently got the engine light with the code P0304 - misfire No.4.
Lately it was starting up rough from cold, chugging at first like a motor that was off a cylinder but coming good after a few seconds and then driving well. After some research on cartrackers I concluded that coolant leaking into one of the cylinders was the problem and decided to change the upper and lower manifold gaskets.
The cleaning took forever as the lower manifold was pretty well clogged (the 98 has the one piece Plastic plenum) so I hadn't time to get it all back together (plenum, throttle body etc still off) and won't get back to it until next weekend.
My question is that since the last two startups were particularily rough sounding what chance is there of more serious engine damage that I should check for before completing the rebuild?

[12Ounce]

Glad to have you onboard. Haven't heard from 'tree or Wrestler.

12Ounce aka Fordfan.

[Ulsterman]

Originally Posted by 12Ounce

Glad to have you onboard. Haven't heard from 'tree or Wrestler.

12Ounce aka Fordfan.

Thanks for the greeting but what about a few words of wisdom?

[12Ounce]

Be sure to floss daily! LOL.

I sorry I don't have anything to offer concerning your '98's problem. But you won't have to wait long before one of our resident experts attends to it.

I've had some luck using compressed air into plug fitting before... making sure the piston was TDC etc. ... then using hose as stethoscope to locate air/water leaks.

[12Ounce]

Ulsterman
Read what this person observes about head gaskets:
.
http://www.babcox.com/editorial/ar/ar90134.htm
.
Good luck!

[Ulsterman]

Originally Posted by 12Ounce

Ulsterman
Read what this person observes about head gaskets:
.
http://www.babcox.com/editorial/ar/ar90134.htm
.
Good luck!

Thanks for your help it is greatly appreciated. here's something I haven't figured out just yet......
On the lower intake manifold there are two ports per cylinder - one circular and the other sort of oval shaped contains the egr port in what I imagine looks like some sort of bronze bushing. All of the ports were filthy with oil gunge except for the circular one going to cylinder No. 4 which was spotless but had a green coloration. I assume this has been purged clean by hot coolant / vapor being drawn in on induction or less likely escaping past the intake valve on the compression stroke after startup? The other port to that cylinder wasn't nearly as clean but it's egr 'hole' was the only one not clogged up.
Whattya think Fordfan? Is this a typical situation to find when replacing the lower intake manifold gasket?

[12Ounce]

There have been instances where the lower gasket leaked coolant into the induction stream. Usually cyl #1 or #4. I think what you are seeing is good news of a sort ... it kinda takes the head gasket off the hook.

My guess would be that all you have is leaking lower intake gaskets.

When I did my intake manifold job, I replaced the lower gaskets and seals along with the uppers ... only because, at the time, it was recommended as part of the action for P0171 and P0174...I never experienced a coolant leak. I did not see any failure locations on the old gaskets ...anywhere, upper or lower....so I guess my problem was all in the isolator bolts. I did notice that the new lower gaskets had been redesigned and just looked more robust.

My EGR jets were all "grundgy"... some totally plugged. I replaced the LH valve cover, which was an upgrade for my '99... and is supposed to lessened the oil pick-up into the induction air. I don't know if this is the case for the '98 or not ... don't think so... I would ask at the parts desk of a dealership. Of course, keeping the air filter super clean and using heavier oils help.

One day I intend to reopen the upper just for a look. The repair now has about 60k miles on it.

[Ulsterman]

Thanks 12Ounce / Fordfan for the reassurance. I'll be back with an update after the weekend when I everything reassembled and tested out.

[Ulsterman]

Well I got it back together but left the upper and lower cowl off just in case.
It started up very very rough sounding like an old diesel with a metallic knocking sound like a valve train or bearing problem. The check engine light came on immediately - P1401 'Differential Pressure Feedback EGR Circuit High Input'. The cooling fans came on very soon after it was started and switched on and off a few times when I was listening to it run.
As it started to warm up the knocking noise died away and the engine sounded and felt first class. I stopped it, disconnected the battery to reset the cel, cleared everthing away then checked all the fluids and took it for a drive to a grocery store approx 8 miles - it drove fine and the light stayed off. On coming out again half an hour later it started with a lesser knocking sound which died away quite quickly but the cel light was back on with the same code.
It's where do I go from here?

[12Ounce]

I would tend to the lower intake gaskets and seals very soon... or is that what you just completed?

It sounds to me like you're starting the engine with a bit of coolant having leaked into the combustion chamber ... thus the dieseling. Possibly some coolant has been sucked into the DPFE sensor, so I would ignor this for the time being. Temporarily ...Disconnect and plug the vacuum hose going to EGR valve to take it out of the picture.

If you have already replaced the lower intake gaskets/seals, I would use compressed air to see if possibly its a head gasket issue.

What do others think?

[Ulsterman]

I have changed the upper and lower intake manifold gaskets - I'll try your suggestion with the egr valve tomorrow and I'll monitor the coolant level. The engine sounds and feels first class once it's warmed up just like you'd expect after all the cleaning of the manifold ports.
Thanks again for your help 12Ounce / Fordfan - any suggestions welcome at this stage.

[12Ounce]

If you are not now loosing coolant, and disconnecting the EGR takes care of the dieseling... I would make sure all EGR vacuum and sensing hoses are cleaned out ... and get ready to replace the DPFE sensor.

[Ulsterman]

It's difficult to gauge whether or not I'm losing coolant for a while having just refilled it after the manifold gasket job as it takes some time to purge all the air out. The engine continues to be noisy until it warms up when presumably the coolant that has collected in the combustion chamber has evapourated - then it runs fine.
I'm now leaning towards a head gasket job having had a good read through the cartrackers forum this afternoon - no. 493 was particularly interesting with all the same symptoms as I'm experiencing.
I'm wondering does anyone have experience of this job and whether it can be accomplished without taking the engine out of the vehicle. I'm thinking that the front head is quite accessible but that the rear one could perhaps be accessed from underneath to remove the exhaust manifold. I've read that the head bolts are not reusable and I know that I may need to have the heads skimmed in a machine shop but I would check once I had them off.
I removed the vacuum line from the egr valve as you suggested and blocked it. I reset the cel and so far it hasn't came back on. I couldn't really detect any vacuum in that line but that aint causing the engine knock and can be investigated another time.
Any comments 12Ounce and others?

[12Ounce]

It may be the head gasket ... but it would be disappointing to do the replacement and discover a different problem.

Possible test: One morning after a normal shut down the night before:
. Remove all plugs
. Have someone crank ...it should really spin with no compression...the engine while you hold a small mirrow, or other clean "target", in front of cyl #4 and #6. Did #4 "wheeze out" coolant ...or engine oil... compared to #6?
.(If you seem to get a lot of "stuff" out of all cyls, you may have a PCV system sucking too much engine oil out of the crankcase.)
.Now that all cylinders are purged, replace the plugs. Does the engine start up without dieseling?


By the way, I'm one of those who removes the cowls to get to the rear pllugs ... makes it fairly easy for me.

Another thought, have you ever tested fuel rail pressure before start-up?

[Ulsterman]

Originally Posted by 12Ounce

It may be the head gasket ... but it would be disappointing to do the replacement and discover a different problem.

Possible test: One morning after a normal shut down the night before:
. Remove all plugs
. Have someone crank ...it should really spin with no compression...the engine while you hold a small mirrow, or other clean "target", in front of cyl #4 and #6. Did #4 "wheeze out" coolant ...or engine oil... compared to #6?
.(If you seem to get a lot of "stuff" out of all cyls, you may have a PCV system sucking too much engine oil out of the crankcase.)
.Now that all cylinders are purged, replace the plugs. Does the engine start up without dieseling?


By the way, I'm one of those who removes the cowls to get to the rear pllugs ... makes it fairly easy for me.

Another thought, have you ever tested fuel rail pressure before start-up?

Thanks again for the help I'll follow your prescription but it'll be the weekend again before I can really get back to it.
How do you check fuel pressure? buy some sort of gauge? there was plenty of pressure when I released it at the valve on the fuel rail by the front injectors before removing the lower manifold.
Before startup, following the manifold job, I removed the sparkplug from No. 4 cyl (which had triggered the P0304 misfire code and had the 'bleached' intake) and cranked the engine. I was alone and couldn't observe closely but on inspection I couldn't detect anything much having been spewed out. The engine fired immediately, which I wasn't expecting, and ran pretty rough so I shut down and cleaned and replaced the plug. I'll try your suggestion with all of the plugs out and inspect anything ejected after the engine has cooled overnight from normal operating temperature.
I'm curious about only being able to detect very little or no vacuum on the line to the egr valve when the engine was running. Where does the other end of that line go so I can remove and clean it out?