98 Windstar P0304 Other Problem?

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?

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

12Ounce aka Fordfan.

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?

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.

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

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?

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.

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

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?

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?

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.

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.

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?

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?

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?

You will NOT have vaccum to the EGR valve at idle.....It will open only when driving. I am not sure of all the inputs that the PCM uses to determine when and how much EGR flow to command....but the vaccum is regulated by the PCM signal to the EGR vaccum regulator solonoid.....which is mounted to the back of the upper intake manifold. The source of the vaccum to the EGR vaccum regulator solonoid is a line that connects to the same vaccum line that goes to the PCV valve.....which enters the upper intake manifold at the top....right next to the throttle body and IAC (Idle Air Control).

Your 1998 windstar has a different....and much more reliable upper intake manifold than what is found on the '99 and newer years. So you are not going to have the isolator bolt issues....the TSB for the P0170 /174 codes.

The DPFE is a common failure item....and easily replaced.

I have not been through the head gasket / lower intake manifold gasket issues.....with my '96.
From what I have read.....you DO NEED to change your oil....PRONTO!!! The reason is....if any coolant got into the engine oil....it will take out the bearings in the engine......

On my '96, the fuel pressure check point is, I think, the same place that you released the pressure.....The center of the front fuel rail. Just like a tire valve. I don't know off the top of my head what the correct pressure should be.....and if it is the same for the '98.

Oh....also very worth doing....as you have them out..... Check the ends of the fuel injectors...the spray end. It is normal for crud to build up inside the plastic cup that is over the end of the fuel injector. Spray some carb. cleaner into there...and flush it out. I had a P0301 code.....that ended up being caused by just that. They were all dirty, even after several runs fo fuel system cleaner.

There are gauge and hose testing kits available for testing the fuel rail. I have one, but just using the "shop rag around small allen wrench" method on Schraeder valve is what I usually do. ...while the key is "off", of course. The rag should get wet..but if gas "spews", indicating intrained air, there may be pump issures. I'm guessing you don't have a fuel pressure problem... but keep it in mind.

The control line to the EGR valve comes from a vacuum regulator/solenoid control valve mounted ont the firewall (on my model). At idle, you should feel almost no vacuum on this hose.. not enough to open the EGR valve. Also check the lines at the DPFEgr sensor mounted on front of engine...more apt to be crudded up.

Thanks so much for the replies and info 12Ounce and Wiswind.

12Ounce
I too doubt very much if fuel pressure is contributing to the problem. I looked at the lines to the dpfe and they were pretty clean but I intend to change this sensor as its known to give problems but right now my priority is to cure the engine 'knocking' at startup and then to irradicate the fault codes. This weekend I intend to try your 'remove the spark plugs' test. Meanwhile I'm investigating head gasket sets and change procedures.
By the way your reply is listed at 5.20am? insomnia? I'm on my way to work at that time but I sincerely hope my windstar's problems aren't causing you to lose sleep?

wiswind
I think I would have preferred to get the plastic plenum apart for cleaning when I did the lower intake manifold job recently - I was just able to shake some solvent around inside it but I agree it does seem to cause less problems than the later models.
I fully intend to change the oil but the vehicle is not being driven right not until I can cure the knocking at startup which 12Ounce and I suspect is caused by coolant getting into the combustion chamber/s. I even bought some heavier oil as suggested by 12Ounce. I fear that I will end up changing head gaskets soon and the oil will be changed at that time with no driving in between.
As said above I believe that the fuel pressure is ok and I intend to change the dpfe anyway.

wiswind - I cleaned the injectors when i had the lower intake manifold off and sprayed throttle body cleaner inside as you suggest

No, no ... just too much beer and bad kidneys. LOL.

I have the vaccum solonoid for the "Evaporative Canistor Purge Valve" mounted on the firewall.....Which also gets its' vaccum from the same place that the EGR Vaccum Regulator sololoid does......

Well I'm not really any further on.
First I tried 12Ounce's recommended removal of all the sparkplugs and cranking the engine - couldn't detect anything being ejected from the cylinders at all and I wiped each plug opening afterwards to check. I replaced the plugs and the engine started with the same knocking noise though it didn't seem as loud (which disappeared once normal operating temp was reached) and the cooling fans cycling on and off - the cel came back on with the same P1401 code.
Next I tried to follow one posters test for a failed head gasket by driving the van to Autozone (30 mile round trip) and borrowing their cooling system pressure tester. The first test told me that the radiator cap was faulty which I replaced but the guys at Autozone were unable to find a suitable sized adaptor to connect the tester to the radiator neck to allow me to pressure test the windstar's cooling system. Bit of a wasted trip however it does look like the engine has ceased losing coolant though so some good news.
Rest of the weekend I went up to my wife's parents place and 'resurrected' her old 93 Ford Festiva and got it running so at least she's no longer grounded while I'm at work - at 140,000 miles the little Festiva still runs fine having seen nothing more than routine maintenance since new. Oh and I did my taxes intending to finance the windstar repairs with the refund.
My next plan for the windstar is to replace the DPFE sensor and make sure all the vacuum lines are clear but I'm beat after that. Any ideas or words of wisdom appreciated guys!

Well, thats good news! No coolant in combustion chamber!

I had not noticed that your code had changed from P0304. Change that DPFE sensor and I bet you're home free.

Well, thats good news! No coolant in combustion chamber!

I had not noticed that your code had changed from P0304. Change that DPFE sensor and I bet you're home free.


Here's hoping you're right my friend - Thanks once again!

Right now...I get a very anoying noise....more of a rattle.....and have tracked it down to the insides being loose in the rear-most catalytic converter.
I have put the large "hose" clamps onto each converter heat shield as the FORD TSB says to....but when I thumped on the rear converter....I could still hear the rattle. If you have loose heat shields (would be caused by a broken weld joint), go to the PLUMBING department to get the large hose clamps..... and install one over each weld point on the converter....(2 per conveter).

Your DPFE sensor change is an easy DIY item....and you can buy one at many auto parts stores.

My wife is picking up one of the sensors for me today so i'll fit it this evening when I get home from work and let you guys know. 12Ounce was for betting so the odds must be good!
As for the cats I'll take your advice wiswind and put the clamps on my to-do list.

Well 12Ounce right once again!
I changed the DPFE sensor yesterday evening and the van started up sweet from cold - engine noise gone completely. I've now driven it about 50 miles and so far no check engine light so it's looking good. I'll drive it to work today and tomorrow and watch the coolant level closely. If all goes well I'll flush the coolant at the weekend and change the oil. By the way I bought some castrol 5/50 synthetic to change to a heavier oil after the egr port cleaning / manifold gasket job as you suggested in another thread.
I'm just curious to know what was making that knocking noise from the engine - like a cam / valvetrain component or a bearing gone bad but disappearing once normal operating temperature was reached?
Thanks again for you help.

If you were working on a '99, I would suggest the noise might be the "loose" inner piece in the upper manifold... the one I like to secure with RTV to help dampen vibrations.
But the '98 probably has a totally different upper manifold design.

So I don't have a clue!

Well the noise shall remain a mystery but it was a worrying mechanical knock. At the weekend I put everything fully back together, flushed the coolant and changed the oil and filter. All's well that ends well so they say.