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Engine Misfire Adventures
07-07-2011, 08:39 PM
First off, I'm sorry for the length of this post. I have been fighting an engine problem for some time now. 2000 3.8l with 185,000 miles. Wife reported that it wasn't running well, stalls sometimes when doing slow turns, sounds like a truck, etc. Oil consumption was up and mileage down. Also I noticed last fall some oil spotting on the garage floor. Some days worse than others, mostly when oil level was full.
I started by changing the plugs, wires, and coil pack back in March. Plug #2 and #5 were fairly crusted. Also cleaned the MAF sensor and installed a new air filter, and ran two cans of Berryman's through the fuel system. Did the isolator bolt fix years ago, and have recleaned the egr ports once at about 140,000 miles. It seemed to be doing better, then in late May CEL came on. Checked the code as misfire #2. Started the van and it seemed to run okay, CEL not blinking, so I cleared the code and waited. 2 days later wife reports CEL on again. I expected to see misfire #2, but got the code for lean on bank #1. At this point I am thinking fuel problem but not wanting to throw dollars at something I can't really diagnose.
Took the van to a local shop I trust in mid June. Long talk with the owner about everything thats going on, and what I've done. After scanning the van they reported that both upper O2 sensors were out of paramaters. After the new sensors were installed, bank #2 was perfect, bank #1 a little lean but not enough to trigger CEL. During a test drive they felt a noticable vibration. Hooked it back up to the test scanner and found cylinder #2 dead. Pulled the plug out and it was totally gunked up. Scan indicated the engine computer had no ground sense from the #2 fuel injector. They shot the wiring and found that it was okay.
So they called me with the bad news that the van needed a new computer. The problem with that is only Ford can program the security features of the new computer. So after the new computer was installed it was towed to the local Ford dealer. Since they were not getting the big dollars for the computer install, they were not eager to do the programming.
4 days later the van was towed back to my mechanic. Put it all back together, back on the scanner, both banks good and no issues at idle, but had slight #2 misfire and vibration when reving the engine. They did install a new plug by the way. They tore it back down, put a new fuel injector in #2 ( no charge ) and viola, it runs like a top. Total out the door $ 800 bucks. $ 160 of that went to Ford for the programming. A computer from the Ford dealer alone was quoted at $700.
On the way home stopped at Autozone and got oil and a filter, as it was due to be changed.
Its been a couple of weeks now, and not only is the oil consumption problem gone (less than a quarter of what it was before), but the oil leak is gone as well. Not a drop on the floor. Not sure if it really needed a computer or just a fuel injector, hard to know, but they did a lot of work to make sure it was right before they sent it back to me. Also highway fuel mileage is back to 20.3 mpg. Hope this info helps someone!
07-08-2011, 07:26 PM
It is great to read that all is well now.
That is a problem that needed diagnosis by a good mechanic with the right equipment.
The "Ground sense" for the #2 injector.......there is your + voltage sitting at 1 side of the injector....and the PCM connects the other side to ground in order to energize it.
So.....all the current to make the injector work flows through the PCM, so no ground through the PCM, no injector operation.
The 3 coils in the coil pack work the same way.......+ voltage at 1 end of each coil....and the PCM pulses to ground to fire each coil.
07-27-2011, 01:40 PM
I'm close but no ray of sun shine. 98 windstar 3.8. I want to keep it. Tis is the biggest pain now; new crat engine, DPFE sensor, vapor management valve, EGR valve, air filter, spark plug wires, and coil pack all brand new!
Van hesitates to the point bogging down, and may stall. If I. Attempt to push it by giving it more fuel, missfire code comes up and blinks. When I stop the van and turn it off, then restart the van, code remains without blinking. When I clear the code, no code appears at all.
Does anyone have an idea before surrender to the Dealer!!
08-02-2011, 02:58 PM
I reread the previous message. Does this mean that I do have to go to ford for the adjustments for myPCM, since I had already replaced my PCM with a rebuilt from a company that Ford parts dept. Directed me to.
08-05-2011, 11:29 PM
I would expect that the PCM would work out of the box....it should have the latest program.
It WILL have to learn the drivability information as you drive.
That might cause the transmission to shift at less than ideal points as it learns......but nothing super noticable....and curtanly NOT misfire issues.
Did you use Autolite or Motorcraft brand double platinum plugs (platinum on the center electrode AND the ground tab)?
The fancy multiprong plugs have been noted to cause misfire issues in the windstar.
Also.....verify that you have good spark plug wires.......maybe take a look under the hood when it is dark outside and the vehicle is running at idle.....see if you see any sparks under the hood around the plugs, plug wires or coil.
Do the IMRC actuators pull the IMR shafts from OPEN to CLOSED when the vehicle is started up?
I would get the OBDII code(s) read.....if you don't have a code reader....many auto part stores, like AutoZone will read them for you, for FREE.
Make SURE to ask for, and write down ALL the numeric codes that come up.
Another TEMPORARY test to do.....to eliminate the EGR system from being the issue......remove and plug the vaccum line that goes into the top of the EGR valve.
Take the vehicle for a drive......does the problem still happen?.....
if yes, then the EGR is not the issue.
If NO, then the EGR is the issue........DPFE, clogged EGR ports in the lower intake manifold are the 2 most likely causes.....EGR valve rarely fails on the Windstar.
Don't forget to reconnect the vaccum line to the EGR valve.
This test should cause a OBDII code for lack of EGR flow.
There is the possibility that you got a defective PCM....but the things that I mention to check are cheap and easy........and I would try that before swaping expensive and already replaced parts.
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