anybody ever make their own spark plug wires? stumbling in boost...

[alloyguitar]

My car's having an issue with, for lack of a better term, falling on it's face at around 4 thousand rpms...or 8ish lbs of boost. Pretty much whichever comes first. In first gear it feels like it hits a wall of missing, and in second (and so on) it starts bucking VERY bad. Like fuel cut, but I have fuel cut eliminated via maf-t.

I'm beginning to suspect that it's my plug wires to blame. When installing the gt4088, and assorted goodies, I used wire off a spool of accel 7mm (I believe) that I had in the shop. My coilpacks are relocated to in front of the clutch master cylinder, which is why the stock wires would not have worked.

The plug gap is set at .25ish, and I'm running ngk's. Bkr7e's, if I remember correctly. There are no boost leaks, as well.

I have done this same plug wire setup on stock supras, but never on a car with a larger than stock turbo, which means (in my eyes, at least) that it could be the wires, or possibly the coil packs to blame.

Anybody care to chime in on this?

 

[figgie]

coil wire? Like solid strang of copper, aluminum etc?

More than likely EM/RF interference with the TCCS.

There is a reason that absolutely NO car with ANY sort of electronics uses solid core wire and you are finding out first hand why. They all use Carbon WOUND center conductors to supress the EM field that is being produced by the typical 30kv.

Even though it worked before.... as the boost level goes up, the power needed to overcome the new Combustion Chamber pressure increases so the length of the spark is cut but that means more amperage meaning a stronger EM field.

 

[jdub]

Any codes?

 

[alloyguitar]

It always throws codes because of the heater circuit on the o2 sensor being gone...Hopefully I can get down to the car soon and answer that question more accurately.

Figgie, I have a spool of accel 7mm plug wire. As in, the kind you would get in those "make your own plug wires" kits from advance/auto zone/etc...Only difference is that mine is like 100ft. long, instead of little pieces.

Like this:

It is NOT spiral wound wire, like it sounds you were assuming. I would NEVER, EVER try that.

I guess it could be the timing, as I'm not sure what it should be set at. My wastegate spring is at 13lbs(give or take), so I wouldn't think that I could advance/retard any for that amount of boost.

 

[alloyguitar]

P.S. if I mod could change the title, I meant to say "spark plug WIRES," instead of plugs...

...I'm an idiot.

 

[figgie]

It is NOT spiral wound wire, like it sounds you were assuming. I would NEVER, EVER try that.

Umm

I think you are mistaken.

Spiral wound is what you WANT. Solid core is no good for EFI application due to the EMF created. By soldi core, that means a core of metal either in one solid piece or strands.

So again, are you using the Carbon Graphite version, which is the spiral wound carbon graphite I was talking about or the Copper tinned which is the solid core?

http://www.mr-gasket.com/pdf/sparkplugs/Wire_Summary.pdf

 

[alloyguitar]

Ohhhhh, okay. I thought you were referring to spiral wound like wiring for lights and such. A bunch of small wires wound together. Like 12 gauge and whatnot.

It's the carbon graphite version, I am 99.8% sure. Is there any reason this would cause my issue? Too much resistance, perhaps?

 

[IJ.]

I use MSD 8.5mm GE sets that I trim to length to match my 6 coils then terminate them using new boots and crimp connectors.

Got any pics of your wire routing?

 

[alloyguitar]

They're running through the spot where the coil packs used to sit on the valve covers, between the runners on the intake manifold, and then to the coils.

Unfortunately I don't have any photos at the moment, but I'll be sure to snap a few the next time I'm near the car (saturday, probably)

 

[IJ.]

Make sure if the wires are running together they have plastic seperators, they may be crossfiring. (run the car in the dark with the hood open you'll see it if they are)

 

[Clip]

i've heard you can take a squirt bottle and lightly mist above them to encourage the wires to arc if they aren't readily doing it.

 

[alloyguitar]

I'll check that out. At the moment they're just zip tied together (probably not my brightest idea), so that could be the cause.

...Any other ideas what could be causing the issue?

 

[IJ.]

^ Understatement of the year...... :nono:

 

[alloyguitar]

lol. That never even occurred to me. My logic was that they run together between the valve covers, so I wasn't thinking that could be it...

...but why would it only do it under boost? the amount of spark energy needed, I'm guessing?

 

[IJ.]

Yep as cylinder pressure increases it takes more energy to make the zap happen.

You will often get spark blowout around torque peak as this is the point of highest pressure.

 

[alloyguitar]

Yep, sounds exactly like my problem. If I back out of the throttle to around 20% or less, it climbs past the limit, but if I floor it again at any time, it stumbles again.

Any ideas on how to separate them? just use the separating looms every six inches or so, perhaps?

 

[IJ.]

Just grab some plastic seperators, dropping the plug gap will help a bit as well but there's a limit to how small you can go due to the shape of the ground electrode.

 

[alloyguitar]

Yeah, my gap is at .25ish right now, so I'm not sure how much smaller I could go...

 

[IJ.]

25 is about it on the normal 1.1 plugs.

 

[alloyguitar]

That's what I thought. Well, I'll try separating the wires and pray that it helps. I'd love for it to be something easy for a change.