Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec ?Help tracking down the stuttering problem....Long...

...as an extension to my above post I just created -- now I have to find a good way to clean out the soot deposits in my cylinders from all the spark-misfires. This is why my oil has been getting nasty dark even 500 miles after oil changes (I have 13,800 miles on my car now), the small amount of blow-by through the rings has been carrying the black soot from unburnt fuel into the crank-case and into the oil. Bleh, probally that foaming stuff or somesuch eh? Oh well, now its cleanup time.. TtEl.

Awesome!

Wow!! Finally!! I see a new coil pack & wires in my near future! I will let you know my results. I believe they will be the same as yours.

Thank you BlackPantherSvt, Blackcoog, Warmonger for the perseverance you all displayed tracking down this problem!!

Now, I wonder if my dealer will do what he said and pick up the tab for this little expense? I'll bet he'll deny everything!

fordpartsonline.com here I come!

...Ed

You know, just to be safe, I am going to buy a set of wires as well. I already swapped the coil packs out but no luck.
All of the theories I have postulated to date have been proven wrong, so I am not sure that this latest one about turbulence will hold up either. I hope I am wrong due to the cost, but it still sucks to do so much work/analysis and be wrong. Oh well, it wouldn't be the first time and wont be the last!


EDIT***************
I just want to update this the final time and let you know that the whole turbulence theory is out!
I replaced my plug wires and have found that the stuttering is gone. Don't ask me why there is an rpm dependence and an airflow dependence on the spark, it has eluded me. Lets just say that if a contour V6 is stuttering then its time to check/change the plug wires.
As far as the coil packs, they were not an issue for me, so if I were you guys I would keep and test your old ones to make sure and see if it truly is only the plug wires. I tested my coils hot and cold, and the resistance changed from 13Kohms cold to 16Kohms very hot. With the new plug wires there is no issue even hot, so the coil pack is eliminated in my case. BlackPantherSVT, try your old coil with the new wires and see if it still runs ok.
I ask this as a final test so we can narrow down the issue for other CEG members and save them from spending extra money. Once we know for sure then we can have Lance Kinley add it to the archives as a solution. As of now, my advice is to change wires first since they are only $50 for a set, whereas the coils are bound to be more.
Thanks again all for the diligence in tracking this down. I guess that is a close since I am the last to verify that the symptoms are gone.
END EDIT*************

warmonger

Tom,

Thanks for the follow up...I'll try wires first.

Thanks to all, once again!

...Ed

Hi guys,

Bummer, the new Motorcraft wires did not fix my "stuttering". I ohmed out the coil to 13.92 - 14.01 on each pair. So I'm going to assume its OK. I'm stumped. Maybe we're not experiencing the same problem. When cold or hot, doesn't matter, I get an intermittant, jerky, misfire like symptom at light throttle, noticeable in any gear (less noticeable in 4th or 5th). It goes away under heavy acceleration. I have replaced the plugs w/APP764 Autolites and now the wires with no improvement. I now think I need to review the EGR stuff again now that I got a new digital multimeter. My old analog had given up the ghost apparently.

...Ed

Check for a vacuum leak or some kind of an air leak after the MAF. Also check the primary side of the ignition coil and verify that it is 0.5 to 1.0 ohms across each one. That is done as I explained in an earlier post. That is actually more critical than the resistance on the secondary coils that you measured.

Back to the vacuum leak, that would give you driveability issues at part throttle and go away at WOT. It would be less RPM dependent as well.
Take a look at all the lines going to the air intake boot, and the PCV especially. I got that kind of stuttering when I was taking my manifold on and off so many times, and one day I left the PCV hooked up to the vacuum source but not into the larger hose coming from the crankcase. As a result it was drawing in fresh unmetered air and throwing the part throttle mixture off.
Definitely check vacuum leaks or PCV.

warmonger

Thanks Tom...I'll be all over those lines and intake connections!

...Ed

Hey Edorfox, the fix for my application was the new coil-pack, not the wires. I threw on new motorcraft wires for the hell of it. Also, when I tested the old coil-pack it was when the pack was hot - operating hot. Then I measured it as it cooled back down too. Thats how I was able to tell the differences in resistances when it was hot vs cold; like 3000 ohms difference. Just thought I would reitterate that. In any case, I sincerely hope you discover what is the problem Edorfox. Also, if you are not yet finished on your journey, WarMonger, I sincerely wish you good luck on that as well. Ill keep watching this post and help if I can too.

...as a further clarification to my last post. I had previously purchased Ford 9mm wires and double-plat plugs to try and fix this problem only ~4000 miles ago. This, of course, didnt fix it at all. After replacing the coil pack with a 99 cougar coil pack I have no problems now. So, I had stuttering with brand new stock Ford wires, then with brand new 9mm wires as well - so I sincerely believe the wires we not the problem in the least (in my case anyway). The only time I saw any effect, 100% effect, was the coil pack replacement. My car currently only has 14,000 miles on it. As far as that coil pack goes, that resistance went up crazy in the heat and my problem got worse with the heat, and then I replaced the coil-pack and the problem totally disapeared. Warmonger, you seem to get the resistance difference too. I just havnt done enough testing to indicate whether that is normal or not (maybe it is?), I just know that my old coil-pack was bad. As far as cost for coil packs go, I used car-part.com and found many packs for 50.00. You just need a 99 or 2000 cougar or contour v6 coil-pack. Those Taurus coil-packs work too. They are all the same I believe. Just in case anyone decides to go that route. Well TtEl.