MongooseGA

iTrader: (6)

Long story short- A few weeks back I had a bad coil on the passenger's side of the engine. Replaced the coil with a new one from Advance, and voila, engine runs perfectly.

After driving for a bit, the engine developed a rough feeling. A slight sputter under acceleration. Cruising at a consistent engine speed seemed fine, but increasing throttle brought in the issue. Idle is slightly rough as well, but the engine does have power.

I checked the wire to the new coil and noticed the insulation was ripped near the boot. I figured they were arcing so I went ahead and replaced with all new NGK wires and NGK iridium plugs. Engine ran great.

After driving a bit again, the same sputtering came back. I unplugged the coil and the engine was much worse. Tells me the coil isn't a dud. I checked the connector from the engine harness to the bottom of the coil and noticed the interior plastics are completely missing. My thought now is that since the 2 wires inside the connector are really just free-floating right next to each other, their signals are interfering and causing the rough acceleration.

I've got brand new OEM connectors coming in this week, and I'm hoping they solve the issue. In case they don't, does anyone have any other thoughts as to what this issue might be?

FWIW, caps and rotors are new within 15-20k miles. New plugs, wires, clean IACV...

ArkLaTexSC

ECU is probably your issue, easily before wires messing with eachother.

MongooseGA

iTrader: (6)

ECU professionally rebuilt within a year.

The problem only comes/goes when I've played with the coil or the wire running to it.

ArkLaTexSC

Ah, well, I'm lost then. Anything stripped of insulation is a problem though. Fwiw, neither of my two coil wires had their clips (both broken) and worked fine.

MongooseGA

iTrader: (6)

Damn. I was really hoping that having no insulation in there would be causing this...

ArkLaTexSC

As long as each wire has insulation (ie no bare metal) it's not an issue, at least at these voltages.

MongooseGA

iTrader: (6)

That's basically what it is. They're inside of the connector housing (black plastic oval) but the two metal ends are exposed and right next to each other. There's no insulation between them at all. I'll get a picture of it tomorrow when there's light.

t2d2

iTrader: (8)

I can't explain why the problem comes back whenever you mess with the coil and wires, other than that being the nature of these finicky beasts, but the symptoms sound exactly like what I experienced before last week's IAC Valve breakthrough.

https://www.clublexus.com/forums/per...ance-tips.html

I too chased down ignition possibilities early on, per many suggestions.

MongooseGA

iTrader: (6)

I'll have to double check my car, but when I had the IACV out over the summer, I learned that I have the version that can't be cleaned like the guides all show. Earlier models had a valve that could be disassembled for cleaning, mine can't. But, I'll check again. If it were the IACV though, I would expect it to have been an issue right away at start up, right? Not something that would come up after driving for a while?

t2d2

iTrader: (8)

Ooh, that sucks. I do have a spare of one of those non-serviceable ones, but I have no idea if it's any good.

Mine was always sporadic, coming and going from day to day, from drive to drive... I think it's something that interacts so closely with the TPS and MAF, lots of variables can affect when it acts up.

MongooseGA

iTrader: (6)

I'll try out these new connectors when they get in, but hopefully I don't need to keep buying anything else. Everything was perfect until the coil went bad and I started moving those wires around. Do you know if the serviceable IACV would be compatible on the newer engines?

t2d2

iTrader: (8)

I'd say it's 50/50. The black housing is smaller on the non-serviceable one, but the bolt holes are identical, the water and air lines are in the same place (but the air line barb on yours is quite a bit bigger; you can fit it over the barb on the serviceable one), and the electrical connections look to be the same visually (a spare connector fits both).

The one part I'm less confident about is the hole on the backside of the metal housing. The serviceable one is a straight shot directly in the center, while the non-serviceable one is off-center and angled. However, the latter's valve looks like it might extend through centered once the angle is accounted for -- the shaft is actually straight, only the opening is angled -- I just can't be positive because mine is in the retracted position. I would guess there's some difference in the intake plenums that the different cutouts on the backside of the metal housings necessitates.

The tips of the shaft on the two are also different. I can see a flat head on the non-serviceable one. Again, that might have to do with the shape of the opening on the plenum that is filled when the valve extends to shut off the air bypass.

MongooseGA

iTrader: (6)

Here's the inside of my connector. As you can see, the wires are free-floating within the housing. The gunk between them is just dielectric grease. I just considered that since there's nothing in there right now holding them in place, the issue could be that they're not sliding over the male ends on the coil correctly.

Thoughts? The new ones should be here by Wednesday. I'll be able to find out for sure it this is my issue, unless someone else has an idea that I can check before then.

t2d2

iTrader: (8)

Wouldn't dialectric grease be a conduit between the two terminals, rather than isolating them? I'm not positive about its properties, but it's used to improve electrical contacts...

MongooseGA

iTrader: (6)

It was on the coil side before I noticed the lack of insulation on the harness connector. Honestly, I've never seen a noticeable benefit to using it, but I do use it on most of my connections out of habit.