Ben

iTrader: (33)

Those plugs don't look the same. I don't see evidence of deposits or glazing on them. The single plug looks like it has deposits (ash?) and is possibly glazed a little. The glazing occurs when there are deposits on the plug that don't have time to burn off before you step into the throttle hard.

I was hoping for a close up of the single plug to see the condition of the insulator.

Braineack

iTrader: (62)

no, they dont look the same at all.

ampz

That looks fine to me, just make sure there are 19 teeth at the 12 o clock position exposed between the 2 cam wheels.

The second set just look well used, if the single one is only a week old, i think it is getting a touch hot at the electrode, bu nothing to worry about, unless of course the ceramic insulator has yellowed.

FWIW the only reason i replaced the HG last time was to stop the oil leak at the back of the head, i thought the rich idle was a mazda factory option

Braineack

iTrader: (62)

I know that #2 had a yellowed insulator compared to the rest the first time I pulled them to do a compression check. I can pull again at lunch.

The only leak I appear to have is from my VC gasket which is tired and old and not doing a great job of sealing, I can see oil drips from it in a few spots. I'm assuming most of the leak that's collecting on the transmission is from that and the cas o-ring, but it's possible it's actually coming from the head gasket.

I'll double check the timing belt again tonight when I pull my valve cover. I'm going to try to retorque the head bolts and see if any got loose. If they did, I have more of a clue.

Braineack

iTrader: (62)

here's #2:






distinctly yellowed compared to the rest on the insulator and less sooty.


#1 is bright white:





#3 and #4 look just like #1.

Braineack

iTrader: (62)

What does it MEAN?!!?!?!

-double rainbow guy

Faeflora

iTrader: (2)

Means I will ban you if you don't bring awesome mt tshirt to dyno day

miatauser884

iTrader: (11)

flaky white is coolant

I've never pulled my plugs right after idle, I should try this as well.

southernmx5

iTrader: (1)

My plugs looked that when I tried to run >15.0-15.5 afrs above cruise kpas and stoich at idle. Regardless of what the lc1 says you are lean or the plugs are not transferring enough heat to the head esp #1.

Braineack

iTrader: (62)

I'm running a fuel map that should have it idling in the 13.5-14.0:1 range regardless of what the AFR gauge says. But it will show leaner than that during warmup and get richer when warm.

southernmx5

iTrader: (1)

Plugs don't lie but the lc1 can and will. Mine is starting to spit occasional e8s again even with the older innovate firmware. Make it richer in warmup and cruise (I know you run 15 or more below 90 kpa) and check them again. My guess is either the lc1 or injectors are to blame and not the headgasket.

Techsalvager

did you ever check from the narrowband at idle?

Braineack

iTrader: (62)

I don't think you understand, with the tune I'm running, warmup should be in the 12.0:1 area. I can watch as I reduce my pulse witdh from 2.5ms down to 1.7ms, as the motor warms up, the AFR show richer. So even with +150% gammae enrichemnts during warmup, the AFRs are reporting leaner than ever before, when I know that should be dictating low 12s - I know this because after I fit my new 255HP fuel pump I never retuned the warmup enrichments (i have higher fuel pressures), and I actually lengthened the After Start Enrichments.

I'm ignore the AFR readings at the moment, but during cruise everything reports pretty spot on. I've been tuning this thing for 4 years with megasquirt. I know what AFR, what pulsewitdh and what kPa I typically idle at. I know what it's capabile of.

Right now, it idles poorly, reports between 11.8-13.5:1 at the same exact kPa & pulse width, randomly misses, and im logging very odd vacuum spikes. Never in the last three year have I ever had it cycle violently if I leaned it up too much...unless I'm somehow acutally idling at 16.0:1 and now I'm trying to idle at 17.0:1 it doesn't make sense. There's a .5% window in my VE table that can upset the crap out of it.

The same pheomonia is happening on different injectors.

I would have bought a new MTX-L gauge last week if I thought it was just the LC1 going bad, but I'm not convinced. I'm running a known good map that gave me 27mpg city driving only. I'm happy with that, problem is, right now with with that same map, it drives like crap, the enrichments are delayed to the point where I have to rev the motor up before releasing the clutch and the idle is twitchy, I had to increase the fueling at idle to keep it happy.

The only other time my car idled in a similar manner was when I did have a HG leak. #4 was drinking water. But it overheated and was obvious, and had solid compression.

My idle valve is also operting at the lowest duty cycle value possible and just barely getting down to 850RPM, this would have brought the RPMs down to ~650RPM before this issue...yet I cant find one vacuum leak...I've exhaust two cans of brake cleaner over every flange looking for a leak.


I'd go get a leakdown test, but I don't have the time/motevation after work. believe me I want to rule out the HG, but I keep coming back to it.

Faeflora

iTrader: (2)

Assuming it will idle, what happens when you turn off your startup enrichments? Everything but the short-decay enrichments.

Are your AIT, CLT reading ok?

What happens when you go in boost? Is AFR aok in boost? Does it lean up?

Long lazy shot: is there juice on the top of your pistons if you shine a light down the spark plug hole?

ismael_pt

iTrader: (1)

bottom fuel injector seal affecting one cylinder and causing a partial vacuum leak?

wayne_curr

iTrader: (8)

Have you tested your sensor using the brake clean method yet?

mazpr

iTrader: (1)

That looks lean to me.

When will the part out be?

Braineack

iTrader: (62)

fwiw: checked the torque on all my head bolts. two on the driver side, far corners were slightly lower than 60 pounds.

Freaky Roadster

Two options for the white crust are coolant or soap from oil. The latter most likely coming from valve stem seals. Are you losing oil at all ???

Thinking about COPS, would you benefit from plugs with a higher temp range?

Just my

rbluemx6

iTrader: (2)

Good thing I've been keeping up with this thread. I finally got around to doing a compression test on my 1.8 with 230k miles. I've been working on a rough idle as well.

cyl 1 = 170
cyl 2 = 170
cyl 3 = 163
cyl 4 = 160

Close within each cylinder and consistent. I think this motor may have some life left for some boost.

I've recently replaced plug wires(ngk) and spark plugs(bkr6e) in an effort to sort out my rough idle.

Heres what my plugs look like after about 5-600 miles.
cyl 4

cyl 3

cyl 2

cyl 1


Plugs almost look similar as brains. Ground straps look whiter in person. I believe that perhaps my oem 230k mile injectors are worn down and causing the engine to run lean, or maybe the seals have a leak as I have smelled a hint of fuel when shutting off after driving around for a while. Also before my LC1 died, afr's were around 14.9 cruising 14.3 in idle and 12.5 wot, all on 93 octane. I have sent out my rx7 460s for servicing, I'll post the results after installing them.