engine misses only when loaded down

[mdshumaker]

I've spent more that an hour reading about missing in the Windstar 3.8L engine. My missing is abit different that what I've read.
I have a 2001 Windstar. The runs fine until your going up a hill or accelerating on the hightway. Then it will begin to miss. The missing will continue until you ease up on the load on the engine. I don't feel any missing when accelerating from a stop and running at constant speed. Only when you load the engine down at lower rpm.

I went after fuel supply first. I installed a new fuel filter. The injector header pressure is 32 psi.
That wasn't it.

My mechanic recommended plug and wires and the Ford dealer agreed. So I just completed installation of 6 new Motorcraft Double Platinum plugs and new Motorcraft wires. (lots of good info on here about getting to those rear plugs. I chose from underneath. It was a breeze) However, this did not fix the problem.

I read in one thread that Advance Auto will read your codes for free, so I'm headed there tomorrow to get that info. Any other idea's on what would make the missing only occur when the engine is loaded down?? I'm open to suggestions.

Marc

[12Ounce]

Well, of course the code is most important. If it turns out to be a "lean" code, I would recommend the following as a low-cost first step:
Lubricate on each end, with gobs of petroleum jelly, any hose/tube that connects to the intake manifold ... the brake booster supply, the PCV tube, the evap supply, etc, etc. A lot of ills can be cured with petroleum jelly.

Of course you may have to open up the intake ... not hard to do.. 14 screws for the top piece. From here you can clean the EGR ports ... and sum up the isolator bolts.

[knl25]

I think missing under load could also becaused by clogged cat, restricted exhaust or EGR not openning if fuel system is ruled out.

[wiswind]

You will not get any codes for the fuel system.
The Windstar OBDII system does not monitor fuel pressure or fuel flow.
In other words, there is no sensor for fuel pressure or fuel flow.

If you suspect the fuel system, have your mechanic connect their fuel pressure gauge to monitor fuel pressure while the vehicle is being driven.....and take it for a drive.

There have been a couple of posts about the fuel pump not being able to keep up with demand, or failing intermittently.

The EGR ports need to be clear.
They tend to clog at the driver's side first.....leaving the ones at the passenger side open.....so cylinders 3 and 4 are the last to be open.
This causes cylinders 3 and 4 to get more EGR flow, less oxygen, and a misfire.
It may not be bad enough to light a CEL yet.
When my EGR ports clogged, the only indication that I got was a misfire, and a CEL for a misfire on cylinder #4.

A cheap and easy way to tell if it is the EGR ports is to remove and plug the vaccum line going to the EGR valve and take the vehicle for a drive.
This WILL light the CEL.....as you will not have EGR flow when there should be....because you have disabled the EGR valve.
If you still get the miss......then that is not the issue.
If you do not get the miss.....then the EGR system would be most likely the problem.
Reconnect the vaccum line to the EGR valve......you don't want to leave it disconnected as it is not good for the engine to run that way all the time.

The CEL will remain lit after the problem is solved......for a set number of "drive cylcles" without a problem.

[mdshumaker]

wiswind,
Well you were right, no codes set. On to something else.
If my fuel pressure was not keeping up, wouldn't I notice that at the higher RPM? I seem to be able to rev fine, and run smoothly in low gears, high RPM. I noted this evening when I ran an errand that it's most pronounced in overdrive at about 1200 RPM. When I push the car to accelerate at this point (keeping it in OD) is when this miss will occur. Once I've got the RPM up to 2000, it doesn't seem to do it. Of course I've also run out of hill by then.

I've put some of that Berryman's fuel system cleaner in the tank. I saw you posted about that being a solvent based product. How's it compare to 44K? I know it's much cheaper.

Since driving the van with a fuel pressure monitor on it is not something I can do with my short pressure gauge, I'll save that option for later. Does the 32psi on the injector header meet spec??

I'll look into the EGR ports. First I need to find the EGR ports and vacuum lines. Mine is a 2001, so pics at your site won't help. If you have any input on located these, that's help. I'll stop by the Ford dealer tomorrow and see if they can show me a drawing.

[mdshumaker]

I think I found the vacuum hose to the EGR valve. If I was correct, removing this and driving the van made no difference in the missing problem. It still is most evident at 1200 to 1500 RPM. Do you think I may have a dirty injector problem??

I've attached a link to a picture of what I removed. If you scroll around you can see the tube with the screw in it and the port where it came off.
Pardon the minimal web site. I'm just starting to play with it.

http://home.comcast.net/~shu5/IMG_1577.JPG

[wiswind]

Yes, that is the vaccum line to the EGR valve.

A slight miss can be real tough to track down.
A fuel pump issue can crop up under higher engine load......less intake vaccum, the fuel pressure regulator will call for more fuel pressure, so that is when a problem with the fuel pump may show up.

I am not familiar with the BG44....I have heard of it....but have not used it.
The Berryman's has solved a slight miss for me several times.....which is why I sound like a broken record about it.....a cheap and easy thing to do.
The windstar seems to be prone to dirt (tar-like) inside the "end cap" over the spray end of the fuel injectors.

The EGR ports (sounding less like your problem as the EGR valve test made no difference) on your 2001 will look the same as mine.....the upper and lower intake look different, but you will be able to identify the EGR ports very easily, once you get the upper intake manifold off.

[mdshumaker]

I'm gonna run some more of the Berrymans thru the tank. (you're right, its cheap. 44K is $20/can) On the outside chance that it is injector related, that may solve the problem over time. Since my wife will be taking this van on a trip in two weeks, I also think I'll take it to my mechanic and see what he thinks. I don't want to risk stranding her if there is a bigger issue developing here.
Thanks for your input.

[mdshumaker]

I took the van to the shop that I've used for years and they came back with an answer that I just don't agree with.
The mechanic claims that I have a "blown head gasket" to use his words. He added some chemical to the coolant and explained that if it gets dark, that's and indication that there is exhaust emissions in the coolant.
If I had a "blown" gasket, I'm certain the symptoms would be much worse. If I had a leaking head gasket that was allowing fluid to enter a cylinder, that would make more sense. However, I've been through the leaking head gasket issue before with my 1995 Windstar. The coolant in the exhaust will foul the oxygen sensor and set the CEL. Also, depending on severity, I'd loose coolant in the system and constantly be adding to bring it back to normal. I do not have either of these symptoms.

This dude tried to sell me on replacing the entire engine in lieu of repairing the blown gasket, claiming that there would be coolant in the oil that has probably damaged the crankshaft bearings. I look at my oil when I drain it. There would be visible evidence of coolant, and there wasn't.
I do plan to take the van to someone else. This guy must be getting kickbacks from Jasper.
Anyway, I'm not going back there.

So I'll try somewhere else, maybe the Ford dealer, since they should have the most current diagnostic machines. I may also try and build a long tube so that I can drive the van while monitoring my fuel pressure to see if it dropping.

Later.

[mdshumaker]

I took your advice from an earlier post and did a driving fuel pressure check.
I made a hose to extend my 16 inch fuel pressure gauge to 12 feet. My wife drove the car around while I monitored the pressure. I think it's working correctly and is probably in spec. Am I right?

Idling and just turned on - about 32 psi.
Normal highway speeds - 34-36 psi.
Stopping and going downhill - 29 psi.
Normal acceleration - 38 psi.
Hard acceleration - 40 psi.

The range is 29-40 psi and seems to adjust to demand just as I'd expect it to.

The missing is getting worse. It's very noticable on hard accelerations now, just when my fuel pressure is highest. In fact, even the missing when the engine is low rpm, but high load, the pressure is at it's highest levels. I think I can rule out the fuel pump and delivery system, but I'm not certain about the injectors. I have another can of Berryman's in the current full tank.

What about ingnition. Could the strength of the spark of the timing pay into this? Does the computer adjust timing according to engine loading/RPM??
I don't have any equipment to test things like this. Looks like I may try the Ford dealer, since they should have the latest in diagnostic equipment.

I took some pictures of the plugs I removed. See anything wrong with them? They look normal to me.

https://publish.comcast.net/photos/index/

Marc

[MARZBX157]

I would look into the coil pack, someone else had been posting about a shuttering issue for a while now and just recently discovered the the ignition coil was the problem all along. The funny thing was that he/she did not get any CEL codes.

http://www.automotiveforums.com/vbul...=756904&page=3

[mdshumaker]

Is there a way to test the coil pack or do you just replace it? I'm assuming it's on the back of the engine where the distributor is. Correct? I'll search the site for info on getting to it. Meanwhile, let me know what you can.

Marc

[tripletdaddy]

Your coil can be tested for resistance across the two circuits. The primary resistance is tested by removing the wire connector. Test for 0.3 to 1.0 ohms across the positive(+) terminal and all the negative (-) terminals. To check the secondary resistance, you pull all of the plug wires and test across each pair of terminals (1-5, 2-6, 3-4) for 6.5 to 11.5 k-ohms or 6,500 to 11,500 ohms.

I forgot to mention to also test to see if each of the plug wire contacts on the coil is not grounded out to the body of the coil. Also test to see if the positive primary contact is not grounded. Grounded for any is bad.

[mdshumaker]

Turns out it was the coil. I took the van to a mechanic that came highly recommended by many trusted folks. He determined that it was the coil, and since he had done all the work to get it out, I just paid him to put the new one in. (Ford parts only) I haven't driven it yet, but my wife drove it home and says it runs great. I also have not established a good relationship with what appears to be an honest, knowledgable mechanic.

Thanks for all your help. This is a great forum for getting ideas and guidance. ( though ya'll thought changing the rear plugs was difficult )


Till next problem.......

Marc