Black spark plugs

I recently changed out what appeared to be pretty old spark plugs.


I bought the Autolite Iridium long life. After research I got paranoid about them not being the correct plugs for my ride, and bought denso iridium plugs. Took these Autolites back out.



Just a couple weeks in the 4 runner, when I removes the Autolites. They are all black on the tips. I know that means too rich fuel to air.

Hopefully you guys can name off some things that may need to be addressed. Things that may cause this. When I put the denso plugs in, the motor seems to be knocking less than before, but still does it under load and throttle.

Things like Maf, 02, air filter, fuel pump, fuel filter, dirty throttle body, bad ignition, leaking exhaust manifold(exhaust shop said the exhaust looked good). So I am in a spot trying to find that knocking, I dont remember this sound when I first bought it.

Im new to the 4runner, and have only had it a couple months. What things have you done to help with the spark plugs looking more correct after years of use?

 

Yes, what I've found in the past, by trial and error on my other cars, each manufacturer has it's "preferred" spark plug brand. Toyotas are more compatible with Denso's, Bosch is more compatible with German vehicles, AC Delco's, GM vehicles... You catch my drift. Not to say that you can't cross em, but your mileage may vary.

I realised this after talking with my dad years ago when the Bosch Platinum+4's came out, and being a guy in college thinking these were "cool", and they would make my vehicle more efficient, I installed them in my then Pontiac Grand Prix supercharged GTP, and was wondering why i was always throwing a Check Engine light.

Now, I tend to stick with what the manufacturers recommend on all of my vehicles.

Cheers,

Sean

 

Well. I dont get many responses on this site. Its a bit discouraging. Its like bumpers and tires is what the talk is

Thanks to the fella that agreed that the wrong brand spark plug...can effect things......

 

I just put brand new denso plugs in it. I was hoping ANYONE may have any insite to anything other than plug brand. That may cause black plugs or a possible knock. Things like sensors that could cause this.before my brand new densos get all charred. I own an 82 f150, and a 1990 toyota pickup. Both are carb and super simple.

As I search the site looking for ideas, its the same loop. About how vvti just sounds like that. Basically when I hit the gas, it sounds like a putter from exhaust or something. At low rmps with a load, and if I hit the gas harder its even louder.

I know on the Atv forum im on, there would be alot of good creative ideas about this topic. And not just a bunch of people saying oohh thats just how they sound.

Im not trying to be an arse. Ive just had alot of negative things in life right now...and hoped for some input, as I spend hours researching, with still the same rabbithole.

I guess that means to just drop it, sale the machine, or take it to a mechanic..because the internet is not giving me anything good.

Sorry if Im negative nancy.

 

The plugs you took out look better than the last pic. Just an fyi, there has been a lot of counterfeit plugs out for awhile now, just a thought. Have you checked your pvc valve? I suggest getting your plugs from a reputable source, run them for a bit, and check them to see how they are.

 

I did get the densos from advance auto parts. It is running a bit more smooth, and with a little more power too. Ive not checked the pcv. Ill do that, thanks for the input. Ill do the cleaning of the throttle body, maf, and possibly replace the pcv soon.

Im not sure if there are other things that could cause the domino effect. The machine runs really good. Just whatever that noisy putter sound is. Is quite annoyong when someone rides with me and they ask, whats that sound? Surely not everyone has explain to every passenger you have, that its apparently normal.

I show between 18 and 20 mpg, which is good news

 

How many miles are on the truck? Sometimes an exhaust leak can cause a sound where its difficult to find. I had a truck once where I couldn't find this strange putter noise and it turns out the top of the muffler where it wasn't visible had a bunch of pin holes. It was rusting from the top down.

 

I agree with what Irizzo asked.

We don’t have eyes and ears into the vehicle and it makes it hard if not impossible to know what is going on based on your description. Here are a couple items I would do:

1. Bring my car to a reputable mechanic for diagnostics and don’t just accept what they tell you. They should show you what they find and give proof. Don’t fall game to the endless money pit.
2. Provide more details on the car in question (idk if you have more than one 4Runner). Taking a hunch this is your 2004 4Runner 4.0L.

Things that I would want to know:

• Is the car stock or is there any aftermarket parts as it relates to the Input, Compression, Power, Exhaust of the vehicle (ie: new sparks plugs, new wires, new intake, new exhaust, etc.)
  
• Where has the vehicle lived most of its life. (Any place with common rust)?
• What is the service history of this vehicle
• Has there been any previous motor work in the vehicle
• Does the noise change at higher RPM’s when driving or standing still?
• Does the vehicle have to be moving for the noise to be evident?
• If stationary and can hear the noise can you pinpoint a rough location the sound is coming from?
• Have you crawled under your car to listen for sounds in the exhaust?
• Have you tried a ?

It could be a number of things causing your issues:

• ECU
• spark plug wires
• bad lifter
• bad spring in headers
• fuel injectors
• MAF sensor
• exhaust

I know this might not help but at least if you never heard of a Mechanics Stethoscope you can get one for $5 and start listening around your car.

Disclosure: I am not a licensed mechanic (for the sue happy people in California). And know reading my post means you were in front of your screen which might be according to the state of California as cancer causing. But idk. Just know everything and anything you do I take no responsibility. (Yes this is a joke)

 

Man, sorry that you're having a bad time in life, but know things will always get better.

In addition to what these guys said, you mentioned getting the plugs at Advanced Auto. Check and make sure that they are gapped properly. Another lesson I've learned is to never take the "these plugs are pregapped from factory." Just make sure they are gapped correctly to the specs in your manual. I'll see if I can find that for your year.

Cheers,

Sean

 

Here it is...



One thing that hasn't been mentioned is, if your spark plugs are OK, check your EGR valve.

Cheers,

Sean

 

The plug type really depends on your ignition system so stick with what the book says...

 

I totally, strongly agree on using the correct plugs. And you can use Denso or NGK and be fine. Looking at it logically, the original plugs you removed were not black but the Autolites were. If nothing else changed it would almost have to be the plugs. Again, I believe that's what it was.

 

Do you have a OBD2 scanner or code reader at all? I'd be curious to see your fuel trims. If they were high, I'd double check that while you were in there you absolutely 100% seated all of the vacuum and EGR lines. I could see an air leak from one of those causing trims to skyrocket with the ECU dumping more fuel to compensate.

Just a thought, and with a cheap scanner easy to check. Good luck dude, I'm pulling my plugs on my new to me 07 next weekend and praying I'm not chasing down something like what you're going through.