Running rough after new spark plugs
 

I had new spark plugs put in my 01 v10 excursion and now it idles rough and when in cruising down the road it feels like its kicking. ( Meaning the cylinder is on its way down and then it fires) It dosnt seem to be missing and there is no codes coming up. I talked to the guy who installed the spark plugs and he said he gaped them. I pulled and tested each coil with a new one. Any suggestion would be great!!!

It didn't idle rough before the spark plugs and i used the stock replacements you would get from a dealer. Does great under a load pulling a 26 foot box trailer with 4000lbs in it. I can barley feel it when i have a load but i can tell its still doing it.

Cylinder is on the way down when it fires? .......never heard that one:-missingt

Meaning The spark is late and im getting a burst of power from a cylinder because the piston is not traveling the full distance. Thats what it feels like. I honestly don know.



I thought the timing was off but i took it to a shop and they said they you cant do timings on these trucks. Is that true?

That's true and this has nothing to do with timing. Whoever changed the plugs did something wrong or maybe a boot is bad. If they didn't change those you should start there. I believe it is missing if it is "kicking".

So i should probably switch out the spark plugs one at a time till i find the culprit.

Is it true you cant adjust the timing on them?

Maybe check the connection to your CPS. It could have come loose?

Sorry what does CPS stand for?

CPS=camshaft position sensor. It's on the front of the motor, driver's side. Follow the path of the serpentine belt between the alternator and PS pump...more closer to the alt. from the middle. There should be a black plug with a wire attached stuck in the aluminum block.

Most likely it's not it, but won't hurt to check connection. This sensor detects the position of the cam and tells the correct coil to fire. If this sensor is bad, the engine won't start. A loose connection could wreak havoc.

Good luck.

Gotcha, I will definitely check that out ty!!!

Timing is not your problem. Listen to your exhaust to hear if it is missing at idle then unplug your cops one a a time while someone is watching for fluctuations in the tach. The boots should have been changed unless it was done very recently.

Sorry, it's more near the bottom of the valve cover on the front driver's side as seen in the photo. Sorry AlaskanEx, had to grab one of your pics from the other post.
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[quote=jh818;10482352]Sorry, it's more near the bottom of the valve cover on the front driver's side as seen in the photo. Sorry AlaskanEx, had to grab one of your pics from the other post.
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You stole his picture! just kidding, actually that's a great shot and I always wondered what it looks like there. It looks like the sensor is between the belt tensioner and the idler pulley, is that it?

No, the other side where it looks like there should be another idler pulley, but it's not there.

Wrecker411, when doing spark plugs, the rubber boot (connects between the plug to the COP (coil over plug)) should be replace and the inside should be coated with dielectric grease. There is no spark plug wire, the boot acts as the insulator. If your mechanic did not replace them, and grease them, he should have.

Did your mechanic give you the old plugs numbered so you could see the condition?
How did you test the COP's?

When the boot is reused, small cracks in them will allow the charge from the COP to escape and ground to the engine block before the charge gets to the plug, thus causing a misfire. From what other report, it will not throw codes for quite a while and you will see other symptoms first (bucking, wierd shifting). Do the easy stuff like replacing the boots first.

Also, consider a computer reset. With the new plugs in, it could still be trying to run the truck like it had the old plugs. To reset the computer, disconnect the battery for 30 minutes. It will run on a standard cycle until it "learns" if it needs to compensate for any errors/motor issues. It takes a couple of duty cycles for it to re-learn with the new plugs once you reset the computer.

While replacing the boots, you can check the COP's at the same time.

PS: There is no timing adjustment on these, unilke older engines. The timing is advanced by the computer instead.

Sorry, I was thinking you said passenger side.

Gotta be anal, sorry. Is the Arrow pointing to it?

im having the same issue in one i just bought today. i bought it as is and i figured it was just the coil packs or plugs. im gonna change the plugs and check the packs this weekend if not this week sometime. whats th best way to check the coil packs?

They are usually good or bad. Change the boots!

jasonodsky,

I dont know what the old spark plugs looked like. When i tested the coil packs, I pulled them one at a time and replaced it with a new one, let it run for a bit to see if it changed. I didnt see any grease. Now when you say boots do you mean the one on the coil packs or is there another? I looked at each coil and they were in really good condition but i would put it passed me that i missed something. It feels like the timing so i will try the battery trick first and see what happens. My gut tells me its the timing and if the CPU is set to the old plugs that would make sense. Wish me luck!!!! lol

Did they guy pull the fuel rails and injectors when getting at your coil packs?..In addition to makeing sure you have all the coil packs securely plugged in, double check that the injectors are securely plugged in as well. I dont want to be an ass, but I sincerely doubt reseting your ecu is going to help anything here.

*edit Also how did you determine there were no codes? Not all codes will set off a CEL so hopefully you had a decent scanner.

I have a code reader and id didnt come up with anything. Its not a expensive one but it reads the codes when the light comes on.

It's not the timing. Replace all your boots. They are the rubber things that go from the cop to the plug, and put a tiny bit of grease on the end of the new spring that comes with them.

well i changed my plugs and boots and its running worse than it was before. im going to disconnect the battery for a while and see what happens. next step for me is to buy a whole new set of coils for summit or jegs.

no problem! thats why i took that pic, hoped it might help somebody.:-drink

Before you blow all your money on cops why don't you try shorting out one at a time while someone watches your tach or hook up an anylizer to it. Your cops are probably all good. Strange how it ran good before that guy put plugs in it, I still think he did something.:-X16

I have changed my plugs twice on my Ex, the first time I did nothing with the coils other that use a dab of dielectric grease. No issues. The second time I changed the plugs was because I got two misfires within two months of each other (bad coils) and I decided to just go ahead and replace all the coils and did the plugs at the same time. Again, no issues and it ran just fine. When I change my plugs I do not remove the fuel rail (you don't have to at all!!) but if someone did I would look at the injector connectors as the wires going to them can get brittle and crack causing too much resistance and misfiring that is the fault of the injectors not the coils. Whoever is talking about resetting the ECU by disconnecting the battery has no idea how these ignition systems work on these things.

When I change my plugs I don't disconnect anything that doesn't need to be disconnected. I learned a long time ago that the the less you take apart the better off you are. Also; my 2000 V-10 has never had a bad cop. I think having some type of resistance is bad for them but I'm just guessing because they weren't around when I was a mechanic. I would put it on an anylizer and get to the root of the problem before you start blowing more money on it.

How'd it all turn out?

WHY REPLACE SPARK PLUGS IN A MODERN VEHICLE ?

Somebody help me out here . Of course in the old days we who hated walking, did preventitive maintainence...points, condensor, dist. caps, plugs, etc, at regular intervals.

But this is not the old days - and last I heard, my local auto parts dealer was fresh out of points, condensor, rotor, and dist. cap for my 2005 V-10......!

I have 140,000 mi. on the "fine wire" plugs - and no sign of a mis-fire. Anyone remember the expression that is NOW very valid " IF IT AINT BROKE, DONT SCREW WITH IT"...

So, someone explain to me why we should EVER screw with a MODERN vehicle's spark-plugs, until and less they start mis-firing ?

My guess is that one of the plugs ceramic insulators was cracked during installation.

take it back to the place that installed them and have the correct the issue.

+1 on that.

It is broke! With a history like that you will greatly benefit from new plugs and boots. I didn't need this scenario to confirm what I already know but I was filling up at a distant city for a couple years and when I got home my gauge would always be between full and 3/4 but after changing plugs AND BOOTS it barely came off the full mark the next time, not to mention a more powerful sound and noticably more power and no it didn't miss a bit before. It is kind of like old stale gas, it looks fine and will run an engine but it is basically shot , like your plugs and boots! They will fire the cylinders enough to not cause a miss but they just aren't doing a good job of it. (Not complete and efficient combustion). The new engines will allow plugs to last longer but like everything else; they wear out. (don't skimp on the boots either!)

Check the O2 sensors with live feed if you can on your code reader. I just changed my plugs & new boots, gap is 1.32mm-1.42mm, my old plugs were averaging gap of 1.65mm 115,000 miles. replaced 3 O2 sensors and it purrs like it was new.

= = = = = =

nope - internal combustion engines dont work that way. The spark either "lights off" the fuel mixture or it dosnt.

Of course plugs erode eventually, and the heat of the engine eventually destroys the insulating capability of the boots. But there is no 'half way' on this. Given the extremely high voltage of modern ignition, they will throw spark across even really bad plugs. That's the beauty of modern "fine wire" spark plugs - they can go a LONG time and get REALLY bad before they fail to "light off" a mixture.

As many have noted in this and other "threads", the extremely powerful ignition systems of modern cars DO most certainly require better insulation in the form of both wiring and boots. So I do agree this is a job better not done "half-way" - do it all or leave it alone. "if it aint broke dont fix it" ! If your motor is running smoothly, leave the plugs and boots alone. }>

Plug after 60K.

Think of it this way. You free up a weekend morning, no kids, no wife, just you and the V10 hangin' out sipping a brew, listening to oldies (70's, 80's, 90's, NPR, Rush, whatever; it's all good). Ease off those Cops and boots, shoot a little compressed air to clear the debris, use pop's old hand tools (he'd be smilin' at you gettin another use out of 'em -he got'em from his pop too) to loosen and check out those well worn plugs. Smile and sip;), hmm amber ale today. If ya like what you see, put those new plugs away and slide them antiquated fireplugs and stiff boots back on and move to the next. Anti sieze or not, up to you in between tunes, oh I love that guitar riff. Ya get to stretch the back and arms on #4 and 5, but they too come out and get inspected and replaced... or not...

Point is, you enjoy the time with your EX- Zen style:-drink.

Some ice-cold Newcastle brown ale...hmmm.

wow ill never work on my truck in the same way ever again !

Wrong! If that were the case the modern day dragsters would still be running the old Corvette dual piont ignition systems with a hot coil and why do engines start getting more power and increased gas mileage after new plugs are installed. The plugs will ignite it but not well enough. It's kind of like trying to light a campfire on a rainy with a match as opposed to using a torch. Someone will chime in to prove you are wrong. I used to think to same thing and it sounded reasonable at the time also.

I guess all that power and added gas mileage was just my imagination. Leaving your plugs in until it misses is a very bad idea.:-X15

Great response...I have the same problem with my 5.4l '06 F150. did not change the COP's....for $60, your right, start there. Thanx again.....