Q. I own a 1997 Ford Windstar van. It has an automatic transmission, a 3.8 liter 200 horsepower engine. It has fuel injection, ABS brakes and about 155,000 kilometers on it.
About one and a half years ago (approx. 120,000 kms.), the service engine light started coming on in the van. It would stay on for a few days, and then go off. It would come on again and again and go off. Sometimes there would be weeks between cycles.
At first I did not notice any performance change in the van. But after this happening several times I did start to notice a slight shaking and engine roughness at about 60 to 80 kms/per/hr. Kinda reminded me of my cars from the 70's when a wire was wet or I had a bad spark plug. I took it in to my mechanic. A guy I've known for years and who has done work on my vehicles for years. He is also an ex ford dealership (15 years) mechanic.
When he checked the van with his computer diagnostic unit, it reported a cylinder misfire. After taking a good look he decided the spark plugs were not so good and changed them. The next day the service engine light came back on, as did the slight engine roughness. I called my mechanic. He was mystified. He said he had heard of a problem with the service engine light on some Ford vehicles. They were very sensitive and could come on when they really shouldn't.
Upon contacting Ford, that was indeed the case. There was no recall on it, but for a one-hour labor charge, a Ford dealership could reprogram the computer and make this light less sensitive. I decided to live with it (ha!). A few months later, the service engine light started to flash for approx. one minute when it came on, and would then go solid. The engine roughness was getting worse. (In the Ford manual it said the light would flash if it was a fairly serious engine miss).
This was all still happening between 60 and 80 kms. /per/hr, the van has always started. I have never smelled anything unusual around the van and have never witnessed any white or black smoke coming from my muffler. So back to the shop! My mechanic. continued to get a cylinder miss code.
He checked several things (sorry, no list). He decided to change the wires. (Yikes! $90 just for the wires.) I myself thought this might be it, so ok'ed it. We went for a test drive. Seemed ok at first. But when we pulled back into the garage, I could feel a slight shake and on came the light. You guessed it. He got his usual cylinder miss code. So he thought maybe the sensitive light was the culprit that time and to see him again if the problem persisted. He said the only other thing he could think of was possibly a bad fuel injector.
Well, I still have the problem, but because I have over $300.00 invested in an ongoing problem I can't bring myself to go back yet. It's been about two months since my last visit. The service light is now on all the time and when the van shakes and the engine runs really rough, the light flashes (about 8 times a day, minimum.)
I've tried premium gas and fuel injector cleaner, but they do not help. The engine oil and transmission fluid look fine. It's really starting to drive me crazy! Your input would be greatly appreciated. Have you heard from any other people with similar problems? Do you think a Certified Ford Dealership would be better suited to tackle this problem?
Thank You,
Dan
A. It seems like your mechanic has done just about everything he can do, short of reprogramming the PCM. About the only thing I can suggest is going to involve a bit of disassembly and inspection. And if the problem is apparent, a bit of money to repair.
You didn't mention what the DTCs were but if any of the DTCs were P0300 through P0306, the problem may be EGR related. Ford issued a TSB 12/21/98 number 98-25-5 pertaining to all 1996, 1997 and 1998 3.8 liter Ford Windstars.
First be sure all of the prerequisite tests have been performed. From the bulletin:
1. Reprogram the PCM with the latest calibration.
2. The following text highlights the most commonly found items which could result in MIL illumination. These items should be checked if prior PCM reprogramming did not resolve the concern:
* Verify that a misfire is occurring. It is possible that certain engine conditions may have to be duplicated for the misfire to be evident. Drive vehicle under different speeds, loads, and engine temperatures. Use the Freeze Frame data to get an idea of when the misfire occurred.
* Perform Service Bay Diagnostic System (SBDS) Power Balance Test. Try to duplicate the misfire based on the captured Freeze Frame data. Duplicate Engine Coolant Temperature (ECT), rpm, and load. Run a power balance at an rpm similar to when misfire occurred. Try to duplicate the misfire by changing engine loads, accelerating, decelerating, and cruising.
* Perform SBDS Spark Duration Test. All boxes should be about the same size. Millisecond duration should not be too high or too low. Check for fuel or coolant fouled, cracked, or incorrectly gapped spark plugs. Swap spark plug to another cylinder to see if miss will follow. Check the resistance of the spark plug wires. Check the resistance of the secondary coil windings, especially it companion cylinders show a concern.
* Perform Injector Flow Test. All injectors should flow within 5% of each other. Swap injector to another cylinder to determine if miss will follow. Replace faulty injectors. Do an Injector Leakdown Test for at least 30 minutes. Residual fuel pressure should not drop more than 17 kPa (2.5 psi).
* Perform Relative Compression Test after duplicating the miss; immediately shut down the engine and perform this test. Verify compression with a manual gauge and perform Cylinder Leakage Test to determine location of concern.
* Check for vacuum leaks around the intake manifold. Check plenum gasket as it may be rolled. Plug evaporator line to Vapor Management Valve (VMV) from the intake manifold. Try to duplicate the miss. Check for a mechanically stuck open VMV. Disconnect the Exhaust Gas Recirculation (EGR) valve. Try to duplicate the miss.
3. If all procedures have been completed, and the misfire concern has not been resolved, the following Steps 3a-3c are to be completed.
a. Remove the upper intake manifold and check the EGR orifices that are pressed into each primary port of the lower intake manifold. If any EGR orifice is missing, replace the lower intake manifold with a new Lower Intake Manifold. If any of the orifices are plugged with soot, clean and unplug them with a pick and solvent. Refer to the appropriate Windstar Service/Workshop Manual for servicing the upper and lower intake manifolds.
NOTE: BE SURE TO ORDER NEW INTAKE MANIFOLD RUNNER CONTROL (IMRC) BUSHINGS (FSRZ-9F955-AB) AS THEY WILL BREAK UPON REMOVAL.
b. Run two (2) cans of Carburetor Tune Up Cleaner (D9AZ-19579-BA, or equivalent meeting Ford specification ESR-M14P9-A), through the engine following contents instructions carefully.
c. Change engine oil and engine oil filter before retesting for misfire.
I would definitely get the PCM reprogrammed to be sure the programming is uncorrupted and up to date. Then have your mechanic take a look at this and he can take it from there.
I would appreciate you letting me know how you make out.
Additional Information provided courtesy of ALLDATA
