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P0302 Misfire on cylinder 2 (rear bank middle)


pperrichetti
12-31-2007, 09:06 PM
2001 Windstar LX - 3.8l V6 w/94,000 miles
Check engine light started flashing. I went to the autoparts store and the above code spit out. I just finished changing the plugs and wires with no luck. I ran the engine at night, and did not see any sparks evident. Could it be the ignition coil? Any way to check before I purchase a new one? What else could it be? The van has 94,000 miles on it. I poured a can of Berryman's in the gas tank.

12Ounce
01-01-2008, 12:26 AM
Swap the cables at the ig pack ... cyl #2 with its "sister" cyl ... I should remember which one is the "sister", but don't at the moment.

If the code changes to the new cyl, ... its the pack. If not, well....

12Ounce
01-01-2008, 09:05 AM
OK, I looked it up ... 2 & 6 share the same coil. Swap 2 & 6 cables for the test.

pperrichetti
01-01-2008, 10:50 AM
Mine has a single ignition coil pack. Firing order from the service manual states 1-4-2-5-3-6, so I should switch #2 wire and #6 wire on the ignition coil only and check to see if code changes to misfire on #6?

wiswind
01-01-2008, 11:29 AM
That is what 12ounce is indicating.
Your coil pack is actually 3 coils in 1 pack.
The engine fires 2 spark plugs at a time, but only 1 of the sparks is being used, the other plug is in a cylinder that is not being used at the time....say on the exhaust cycle....so no fuel to burn at that time.

So, from what 12ounce is saying, plugs #2 and #6 fire together (they are the ends of the SAME coil secondary winding in the coil pack)......so switching the wires at the coil pack will STILL result in the plugs firing the SAME......cylinder #2 will get a spark at the same time as normal.
The only difference is that it will be of opposite polarity.....which makes NO difference at all.

So, with the wires swapped between #2 and #6, both cylinders SHOULD still get a spark at the same time.....but if the problem moves to cylinder #6, then the coil pack would be suspect.
The coil pack can develop a crack in the epoxy body......and the spark goes to ground through the crack, instead of at the spark plug.

If the problem does NOT move, then the problem is NOT the coil pack.

It may take some time, even a couple of treated tanks of gasoline for the berryman's B-12 chemtool to work.
Clogging at the spray end of the fuel injector is quite common on the windstar.
There is nothing wrong with the injector, there is just dirt at the spray end.....not in the injector, but over the spray end....up inside the "end cap".
The berryman's is the only cleaner (and I have tried a BUNCH) that I have found that cleans this particular deposit.

There are other things that can cause the problem, but lets work with the cheap and easy first.

pperrichetti
01-01-2008, 07:51 PM
I was very hesitant about driving the van back to the auto parts store again with the misfire, so I went old school. I used one of the old wires and plugs, hooked them to the coil pack on #2 first, no spark, then on to #6, had spark.

I installed a new coil pack and the misfire is gone. After looking at the bottom of the coil pack, I now see the three coils in one through the epoxy.

My only problem is that the check engine light is still on? I did not have a chance to run the van long today, a quick trip around the block, so I am not sure if it take a while for the system to reset?

I will make a trip back to the auto parts store to see check the code if it doesn't clear after my wife runs it tomorrow. It may be time to invest in the scanner.

I did run the van from the middle of PA back to NJ with the misfire, about 200 plus miles up and down the rolling hills of Rte 80. Could I've damaged something else due to the misfire?

Thanks again for all the help and advice. If nothing else, through the TSB and this problem, I can now take the wipers and cowl off with my eyes closed. It certainly makes the job much easier, and no need to be a contortionist.

12Ounce
01-01-2008, 08:07 PM
You have probably not damaged anything because of driving with the misfire. There is the "remotest" (Is that a word?) of chances that it could lead to sensor or even converter damage ... but, that is very remote.

You need the code read again. I'm guessing you knocked a vacuum hose loose or something .... ??

tomj76
01-02-2008, 02:54 PM
After a severe misfire, it will take at least 3 full cold/hot/cold cycles of using the vehicle to clear the CEL. After that it takes about another 30 or 50 cycles to clear the DTC from the computer memory. The first statement is in the Ford Owner's Manual, the second I read in an OBDII Code Reader manual.

pperrichetti
01-02-2008, 10:00 PM
Glad it is the remotest chance of damage to the converter. When it occured, I asked my wife to see what the blinking light meant by checking the owner's manual. After reading the part about overheating the converter and causing a fire, it said the engine is misfiring. "Avoid heavy acceleration or decelleration until you can get to your dealer." Let's just say she was at the edge of her seat, checking the side view mirror for fire for the next 200 miles, reminding me to take it easy. I told just to take her shoes off and let me know when the floorboards get hot.

It is still spitting out P0302. The only difference is that instead of the check engine light flashing, it is now on steady. The parts store said it was against their policy to reset it for me.

Once the temperature gets back above freezing, I check all the vacuum lines and wires around the work area, otherwise I'll wait and see.

Thanks again.

12Ounce
01-03-2008, 07:43 AM
Hmmm ... still a misfire on #2.

If you have access to a clamp-on type timing light, you can see if the plug at #2 is getting "fire". If it is, then its time to check out the injector and wiring.

If you can get a tube against the injector body, you can hold it to your ear and listen for "clicks" ... compare this sound to sounds from other injectors.

Resetting the code is worthless anyway.

tomj76
01-03-2008, 12:59 PM
I don't think that P0302 code does means that there is still a problem detected by the computer. The computer will continue to report the code until the requred number of cold/hot/cold engine cycles occurs.

When you don't have an OBDII reader that will let you reset the codes, you can disconnect the battery for a minute then reconnect it. You'll have to reprogram your radio settings. The powertrain computer will need to reprogram through the drive cycle (about 50 miles of city and highway driving), but that would be required even if you could reset the computer with a reader.

The CEL will probably turn off by the end of the week since you did the repair on Monday, provided that you drive it at least one "trip" (cold/hot/cold) everyday.

12Ounce
01-03-2008, 04:34 PM
Yep, I agree. I had missed the fact that you have not had a chance to drive many miles.

pperrichetti
01-04-2008, 08:36 PM
The wife drove the van every day this week, and the code cleared by itself. PTL. Once again, thanks 12Ounce and tomj76.

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