New Wires, TINY Jerky Above 3.5k

thatranger · #1 05-14-2013, 04:53 PM

Just replaced the wires with some autolite ones. Have these very small/faint jerks above 3,500rpms.

Engine power feels the very same with these new wires on a side note, and didn't have this problem before.

Maybe the computer needs to get reset? Or theres a common vac line that I might of moved? Feels to me its more like lack of fuel, just a very tiny bit. Doesn't happen above 3,500rpms at all. Idles great.

Engine has ~80k on it.
Everything else has 187k on it.

Spark plugs look almost new. And were replaced 1-2years ago with motocraft plugs. Coil pack looks good, no cracks. No check engine light.

Update: Its now a noticeable jerk. Almost as if the fuel injectors cut off for a second, turn back on, then cut off again.

Sounds like a fuel problem, but: It was not doing this before I change the wires. I drive my truck above 3-4k every time I drive it, a few times a drive. And it did not do this yesturday.

rangerlocal · #2 05-15-2013, 08:08 AM

Try taking off all the plug wires and with some needle nose pliers crimping the connector inside the boot ever so slightly more closed. Gives it a better grip on the spark plug nipple. Try some dielectric grease too to help aid in conductivity in case there's a slightly loose connection with one of the wires somewhere. Make sure no debris got in the coil pack connectors when you removed the wires.

cowboybilly9mile · #3 05-15-2013, 10:08 AM

Is the plug wire routing exactly the same as when it was new? And if you have two plug wires crossing, are they crossing as close to 90* as possible as opposed to them being parallel? Are all wires in looms and you're 100% sure none of them are getting fried against a manifold? I mean, you did mention that it's getting worse, so.....

thatranger · #4 05-15-2013, 10:21 AM

Quote:

Originally Posted by cowboybilly9mile

Is the plug wire routing exactly the same as when it was new? And if you have two plug wires crossing, are they crossing as close to 90* as possible as opposed to them being parallel? Are all wires in looms and you're 100% sure none of them are getting fried against a manifold? I mean, you did mention that it's getting worse, so.....

No the routing isn't exactly the same. Two of the clips broke off, but I tried placing them the best I can without them getting in the way of anything else, and with trying to make sure the wires/ends are not making contact with the headers.

Looms? Don't understand what you mean by looms.

And the wires have to be parallel when running them in the clips from the coil to the plugs? In some areas the wires might 'cross' like the near ends to the coil pack, but nothing too much....

----
It idles and runs perfectly fine. It drives fine, but around 3.5-4k rpms, it'll jerk/miss/buck a little bit. Which never happen till I did the wires....

I also sprayed some brake cleaner (had no carb cleaner) to check for vac leaks, and found none. Its not like I was doing the spark plugs & hitting things trying to remove plugs. Just took off the wires, and replaced them only.

cowboybilly9mile · #5 05-15-2013, 11:08 AM

Despite the leaps and bounds in plug wire quality over the years, it might be possible to crossfire between two (or?) plug wires, especially at higher speeds. One way to do this is for them to run parallel to and to be in contact with each other and for noteworthy lengths, and one way to avoid this as much a possible and to try to make them cross as close to 90* whenever possible. This get's back to the factory routing and using the looms, ie, the devices that hold the plug wires in position. Unless you've got a reason to have to deviate from factory, for example, maybe adding headers, it's preferred to stick to the OEM wire routing, to avoid crossfire issues, wire burning, etc.

There are times, situations and circumstances of course that plug wires must be parallel to one another. However, when this is the case, it's desirable to minimize the length of the parallel run and to keep them apart; the worse is to have them laying against one another with no gap. What I said about plug wire routing, that's the ultimate goal, compromises will have to be made. Which get's back to letting the manufacturer address it and implement the preferred solution.

From what I've read of your situation and what's going on, and looking back at what I've sen over a lot of years and on different vehicles, I'm suspicious of plug wire routing maybe being the problem.

thatranger · #6 05-15-2013, 11:44 AM

Quote:

Originally Posted by cowboybilly9mile

Despite the leaps and bounds in plug wire quality over the years, it might be possible to crossfire between two (or?) plug wires, especially at higher speeds. One way to do this is for them to run parallel to and to be in contact with each other and for noteworthy lengths, and one way to avoid this as much a possible and to try to make them cross as close to 90* whenever possible. This get's back to the factory routing and using the looms, ie, the devices that hold the plug wires in position. Unless you've got a reason to have to deviate from factory, for example, maybe adding headers, it's preferred to stick to the OEM wire routing, to avoid crossfire issues, wire burning, etc.

There are times, situations and circumstances of course that plug wires must be parallel to one another. However, when this is the case, it's desirable to minimize the length of the parallel run and to keep them apart; the worse is to have them laying against one another with no gap. What I said about plug wire routing, that's the ultimate goal, compromises will have to be made. Which get's back to letting the manufacturer address it and implement the preferred solution.

From what I've read of your situation and what's going on, and looking back at what I've sen over a lot of years and on different vehicles, I'm suspicious of plug wire routing maybe being the problem.

Well your posts makes sense about causing them to crossfire. I know with ethernet wires, they have 8smaller wires in them, and each pair needs to be twisted around each other to prevent 'cross talk'.

However from the factory, they are pretty much all running parallel to each other. But since two of the clips broke, they make be touching each other in quite a few places. It was the two clips that routed the drivers side plugs behind the back of the engine. So they are just laying there.

So I need to prevent them from touching each other is the very first thing correct?

Next step is to run them non-parallel as much as I can. But the odd thing is, almost all cars now a days have their wires running parallel using the factory clips.

Just found a pic, so I need to do something like this:

----------

Update, well I had all my wires on my coil pack all in a neat parallel line on each side for the left bank and the right bank. Well I did what was in the image, and just swap some under neather and over the wires and it seems to have fixxed my problem.

I'll be going to school later today and it'll be tested for a longer period to make sure.

But thank you VERY much cowboybilly9mile, no one else would of ever thought about it cross-firing!! Maybe instead of autolight I've should of gone with motorcraft? But the wires say they are 8mm thick. I didn't think that the factory why they wire them, like in the pic, was like that for a reason. However now I know lol.

cowboybilly9mile · #7 05-15-2013, 11:56 AM

Parallel in itself will have to happen sometimes and will have to be delt with, I'd gap them (distance between them) like the factory did and as much as possible. Myself, I've gone out and bought replacement pieces for the plastic looms from the stealership; they get old and break sometimes.

See what they did to the plug wires in that pic of yours for the 6-5 part of the firing order? If the firing order for your engine has two jugs barking side by side in the sequence, or for that matter any engine with a firing order that is like this, you want to keep those plug wires for away from each other. That 6-5 in the pics is a perfect example of a situation where two plug wires, parallel for a noteworthy distance, are the perfect recipe for crossfire. SBC's love to do this on 5-7, same deal, age old area to beware of.

Like I mentioned in my last post, I'm suspicious of the plug wire routing and positions; I'm not guaranteeing a fix but I do see a situation that doesn't sound correct from what you've said, I do know and can say from personal experience that wire routing can cause the problem you're describing (odd that it doesn't continue with higher revs, but I've got a theory), and if I were working on it, I'd eliminate it as part of the troubleshooting/diagnostics/correction process.

thatranger · #8 05-15-2013, 12:04 PM

Quote:

Originally Posted by cowboybilly9mile

Parallel in itself will have to happen sometimes and will have to be delt with, I'd gap them (distance between them) like the factory did and as much as possible. Myself, I've gone out and bought replacement pieces for the plastic looms from the stealership; they get old and break sometimes.

See what they did to the plug wires in that pic of yours for the 6-5 part of the firing order? If the firing order for your engine has two jugs barking side by side in the sequence, or for that matter any engine with a firing order that is like this, you want to keep those plug wires for away from each other. That 6-5 in the pics is a perfect example of a situation where two plug wires, parallel for a noteworthy distance, are the perfect recipe for crossfire. SBC's love to do this on 5-7, same deal, age old area to beware of.

Like I mentioned in my last post, I'm suspicious of the plug wire routing and positions; I'm not guaranteeing a fix but I do see a situation that doesn't sound correct from what you've said, I do know and can say from personal experience that wire routing can cause the problem you're describing (odd that it doesn't continue with higher revs, but I've got a theory), and if I were working on it, I'd eliminate it as part of the troubleshooting/diagnostics/correction process.

The miss starts at 3.5-4k, I'm unsure if it gets worst at higher rpms because I did not try to go any higher then that with it missing. However it did not miss below 3k at all. So it makes perfect sense to me with the higher rpms causing it to crossfire.

Thank you for the infomation. Yea, I was trying to wire them neatly with them running parallel to each other, just trying to make it look nice. But now that I know about this, I'll remember it forever. Never knew about this before. Thats why I enjoy being on a car/truck forum, to learn as much as I can. Again, thank you for posting & solving my issue, its a really odd thing, and most likely no one on the forum would of mention it & it would of drove me crazy, and I would of been replacing a bunch of stuff just trying to fix this.

cowboybilly9mile · #9 05-15-2013, 12:05 PM

Quote:

Originally Posted by thatranger

---------

Update, well I had all my wires on my coil pack all in a neat parallel line on each side for the left bank and the right bank. Well I did what was in the image, and just swap some under neather and over the wires and it seems to have fixxed my problem.

Awesomeness!

Quote:

Originally Posted by thatranger

............But thank you VERY much cowboybilly9mile, no one else would of ever thought about it cross-firing!! Maybe instead of autolight I've should of gone with motorcraft? But the wires say they are 8mm thick. I didn't think that the factory why they wire them, like in the pic, was like that for a reason. However now I know lol.

NP, glad it appears to be working out. I could rattle off a few names of guys here that probably do know about this, there probably are more that' I'm not yet aware of. I don't think I'd have any problem with either flavor of Ford plug wire either. And yes, the reason I'm preaching maintaining and restoring that factory plug wire routing is because they have the time to engineer a great solution into the vehicle, and unless there is a real good reason to deviate from it I'd let the sleeping dog lay. It's a proven design, it's done by a fortune 500 company with an army of staff members, they've got over 100 years dealing with this stuff, they scrutinize the competition and maybe make use of such info, I just can't understand why anyone would want to fight it without a real good reason.

rangerlocal · #10 05-15-2013, 01:04 PM

That's one of the reasons the driver's side coil pack bank is routed 5-6-4, to avoid close ignition in sequential order. But this shouldn't be a problem if you used quality wires. Cheap knockoffs or house brands typically have thin or inadequate insulation around the wires that can make them prone to interference, especially on HEI ignition systems since they use a much higher voltage spike and can jump all sorts of weird places.

It could also be a loose connection at your boot, and wriggling them around changed it. It's funny how the little things and details can royally screw something up that you wouldn't think would matter in the slightest.

thatranger · #11 05-15-2013, 02:29 PM

Quote:

Originally Posted by rangerlocal

That's one of the reasons the driver's side coil pack bank is routed 5-6-4, to avoid close ignition in sequential order. But this shouldn't be a problem if you used quality wires. Cheap knockoffs or house brands typically have thin or inadequate insulation around the wires that can make them prone to interference, especially on HEI ignition systems since they use a much higher voltage spike and can jump all sorts of weird places.

It could also be a loose connection at your boot, and wriggling them around changed it. It's funny how the little things and details can royally screw something up that you wouldn't think would matter in the slightest.

Now, doesn't matter what rpm, if I 'get into the gas' at any rpm, it will want to buck/miss/whatever till I'm out of the gas mostly. Also when I was doing it (forcing it to buck) the check engine light came on flashing, I stopped doing it, then the check engine light went off. Have no idea what the problem is.

It will run idle perfectly, I can also rev it up (like 4k) and have NO problems. Will ONLY do it underload... Also switched back to the old motorcraft wires, and just threw them over the engine, no even putting them in place, and no way they are doing crossfire.

Guess its time to take it to the stealership.

Prages · #12 05-15-2013, 03:43 PM

Flashing CEL means bad misfire. You're sure you got firing order right, and wires aren't grounding somewhere?

thatranger · #13 05-15-2013, 03:46 PM

Quote:

Originally Posted by Prages

Flashing CEL means bad misfire. You're sure you got firing order right, and wires aren't grounding somewhere?

It idles perfectly fine, and will rev in neutral perfectly fine. It only does it under load. No way I mixed up the firing order. I even swapped the old ones back on. It'll drive fine till I 'get in the gas' more then a 1/3 of gas. Once I'm a 1/3 of gas in, it'll start to buck.

When I was in the gas, not letting off, causing it to buck (because I wanted to see if the check engine light will come on) it came on, flashed fast, then the check engine light turn back off once I 'got out of the gas'.
-Which means I can drive it just fine, but if I go pass about 1/3 of gas, it'll buck. The check engine light stays off, unless I make it buck for about 10seconds straight, then turn back off.

thatranger · #14 05-15-2013, 06:02 PM

Update:

Maybe this could be the clutch? I know before, if I were going like at 1.5k rpms in like 4th, and gave it 1/2 gas, the clutch would slip for a second then grab.

The clutch would always do this in 3/4/5, if I was around 1.5k rpm and give it 1/3-1/2 gas it would slip.

However when I'm going like 3-5k rpms, the clutch never slipped.

rangerlocal · #15 05-15-2013, 07:24 PM

Clutch slipping shouldn't trigger a CEL. Can you get the codes scanned and let us know what they are? That'll be the easiest place to start.