These plugs have 10k on them, and my driving is mostly around town, I typically hit the boost hard about once or twice per trip. The first pic is leading, second pic is trailing plugs. These are the stock 9s and 7s.

What is this white powderish stuff on it? I also have a thin layer of this white/tan powder all through my turbos and exhaust.

Dave

 

ide say your running a little lean, what are your cruizing afrs?

 

No idea. I have a stock ECU, and DP, CB, Y-pipe, as my only power mods.

Dave

 

yeah looks lean how many miles on the motor? those mods shouldnt be leaning out your car that much.

 

Well at the moment my boost was hitting 12psi instead of 10 (since adding the cat-back - before that it was 10-8-10). So I know that's getting leaner than it should.

The motor has 14k. I'll pressure test the coolant system when I get things all hooked back up (I have the rats nest out and turbos coming off).

Dave

 

I have the same mods minus the Y pipe and my boost hits 11 and sometimes 12 on transition. you should look into getting a ECU brotha, even thought I'm sure someone will call me stupid or something, but my plugs are similar to yours just a bit more richer and black looking. You can get a pettit unlimited or something for around 400 bucks, it's a good saftey

 

GET MBC SET TO 10 PSI ASAP

 

I know, I know - I have a bigger wastegate pill ready to go in. I haven't been driving it all the way up to 12psi since it began happening.

So when I get it back to 10psi, will I still need an ECU? I don't think I should.

Dave

 

no you wont, but it will be a nice power mod. boost controller is great though.

 

dgeesaman,
My car also has similar mods and I'm just curious. How was the car running...mileage, idle etc. ...with those plugs?

 

A knowledgeable forum member such as yourself doesn't know the answer to this?

The stock ecu runs rich enough to compensate for the air flow mods you have as long as you hold the boost to 10 psi.

 

at least he doesn't act like he knows everything like some people.

The stock ECU is way good enough for 10 psi and even will cover small spikes... but for a extra 300 bucks it's a good saftey mod and will run the car a tad bit richer and get rid of the fuel cut on most ECU's. Of course a power FC is the best and getting it tuned, even if all you ahve is 2 or 3 mods, will improve your cars performance and keep the engine running longer.

 

Dgeesaman, that's weird, because it looks like you are running quite lean with those plugs, but you shouldn't be. Hooking up a wideband o2 sensor sure would help to see if you really have a problem or not. Maybe one of your air/water thermosensors is wonky, or you are having a problem with your injectors or fuel system.

 

If it was a thermosensor, such as the intake air thermosensor, don't they generally cause the car to run rich and generate a CEL?

 

I was wondering the same. Dave, I KNOW you know the answer to that...

I'd say stick w/ a working boost controller, and leave the ECU alone. Your car is very mildly modded, and I'm sure she runs great. I'd wanna preserve that. Plus, being able to pull codes is a great thing But then again, I KNOW you know all this already Dave.

 

No, to be honest, I don't know the answer. I've read about it before (dark = rich, light = lean), but because of the dark and light on them I'm asking.

The car generally runs well, but has had that FD not-so-smooth throttle response down low. Like I said, it runs dangerously high (12psi) since adding the cb and I'm in the process of getting it back down to 10. Also, this winter I noticed that from a cold start and idle, my downpipe glowed once! I figured it was afterburn from the cold start richness, but maybe it's suggesting lean.

I changed the fuel filter last week, and my quick test drive suggested the low rpm/low load smoothness improved. I'm having the injectors cleaned now during this outage. When I'm done I'll have new plugs, cleaned injectors with new OEM orings, newer turbos, and some replaced solenoids. If I ever change ECUs it won't be to one of those lame piggyback types - I'll make the full jump to a PFC and get it tuned well. But right now I see no reason to get rid of the stock one.

The thing about the thermosensors - since the UIM is off now is the perfect time to test them. Will running the FSM tests be conclusive for these parts? I'd hate to find out later those are the kind of parts that can pass the tests but still cause problems.

I wonder if Zach Keller will let me borrow his wideband for a test - considering now he's married and he will be busy swapping in the all-mighty piston engine.

If I pull the stock O2 sensor and put a wideband in its place, will the test for cruising afrs be thrown off b/c the ECU won't be getting a normal O2 sensor signal?

Dave

 

Dave, I think BlueRex and I were referring to you knowing you don't need an ECU, as long as you get a boost controller.

 

Well, yeah, that's certainly true. 10psi rule baby!!

Dave

 

Offhand I don't think the plug is telling you about fuel mixture at all, except that you are burning coolant.

If that is really "white", I think that white powder is cooked coolant. Are you mysteriously losing coolant?

 

Nope, not as far as I can tell. It passed a pressure test a year ago, and I don't get coolant smoke, either.

I've been running Mobil1 10w-30 and Sunoco 94.

So I guess these plugs aren't saying much at all.

Dave

 

God I miss filling up w/ Sunoco 94...

 

I know what the White on the Plugs is...it's called: Ash. Yes, Ash.

Common Motor Oil has Ash added to it. It's basically a metallic detergent they add to the oil.

I've seen white plugs on a wide vareity of cars. That's generally normal.

Your spark plug might be fouled (ie the black spot) because your mixture is too rich, it can be caused by extensive idle.

You might want experiment with a Cold or Hot plugs...see if it makes a difference.

A Cold plug is shorter, whereas a long plug will run hotter. My guess is maybe a Hot plug may work better for you.

 

He's already running 7s and 9s..you don't go hotter than that!

 

OK...well maybe a colder plug then

 

Your plugs are saying "change me more often!!!"

Also, you might want to run colder plugs if you're worried about running lean or detonating.
http://www.ngksparkplugs.com/techinfo/spark_plugs/

-s-