Faulty Brainbox?

[Tarantula]

Also tested three of the blown plugs that I had, two were good and one wasn't, which makes it even more hard to understand. The two 'good' ones were changed in May when I got misfire for cylinders 1 & 2. Both plugs were changed and car worked back to normal.

[wagonrunner]

which is why i wanted to see your "blown" plugs.

[wagonrunner]

the tiida has a plastic valve cover???

The GA's seem to be plastic. Dunno if it's different in the tiida, hence the question.

[Dave]

local GA's were aluminiun and FU units were plastic

spidey, the jacks for wire harness and contact points for plugs were ever cleaned and lubed back?
something is creating a hot spot causes additional voltage to get to the plug

[belalegosi]

pics of "Blown" plugs?

confirmed the sensors are good?
spark plug gaps are right?
if its only happening on cylinder 2, is the injector for cylinder 2 good?
You checked cranking compression?

[Tarantula]

local GA's were aluminiun and FU units were plastic

spidey, the jacks for wire harness and contact points for plugs were ever cleaned and lubed back?
something is creating a hot spot causes additional voltage to get to the plug

shouldn't the additional voltage instead affect the coil pack and not the plug?

Anyhow I'll post pics of the "good" plugs and the bad one as well.

jnqaz I use the original irridium plugs. Problem affects all cylinders is not restricted to cylinder 2 only however cylinder 2 is affected most times. All scans done show that all sensors are good and everything is in excellent working order.

[Dave]

bro with your strange issue, i won't leave any stone unturned if u understand what i mean
voltage would look for the least resistance path when looking to flow

why don't you try copper versions of the plugs u use, if available

[belalegosi]

scan tools are great but don't put your faith in it.

[Tarantula]

Well problem has reoccured yet again, less than 2 weeks after the last time. This time cylinders 1 & 2 were affected. Will post pics of the blown plugs later this week. I'm going to try changing the brainbox first and see how that goes.

[DSM_05]

why don't you try copper versions of the plugs u use, if available

Hard to find copper versions of the Tiida plugs.

The plugs are similar to those "long reach" ones used in the GDI P11's, but narrower.


Also, the HR15/16 has a metal valve cover, but a plastic intake manifold. But in this engine, the intake manifold passes "over" the top of the engine....

[Tarantula]

But in this engine, the intake manifold passes "over" the top of the engine....

this worsens my situation soooooooo much more!

and no Dave, apparently copper versions of the plugs are not available.

[DSM_05]

^^Indeed it does sir, makes changing plugs that much more difficult.

[wagonrunner]

The plugs are similar to those "long reach" ones used in the GDI P11's, but narrower.

In the what?
what's the model of the plugs being used now?

[Tarantula]

I use original Nissan plugs LZKAR6AP-11.

[DSM_05]

The plugs are similar to those "long reach" ones used in the GDI P11's, but narrower.

In the what?
what's the model of the plugs being used now?

I was comparing the Tiida OEM plugs to the "long reach" plugs found on the QG18DD engine (not DE), that was found in some P11's and B15's. That engine was a Gasoline Direct Injection (Neo DI printed on the plastic engine cover). I called it GDI for short, although that's technically incorrect since "GDI" was the nomenclature used by MMC, not Nissan.

The Tiida's plug is of course narrower, longer, and of different dimensions. Never said it was the same.

I use original Nissan plugs LZKAR6AP-11.

Sounds about right. I had bought the FXE20HR11 Densos some years aback to try. AFAIK, those are the Denso equivalents to the LZKARs.

[Tarantula]

Anyway I'm going to take jnqaz's advice and change the crankshaft position sensor tomorrow. Hope that works.

[~Vēġó~]

crankshaft position sensor will be changed....trying your suggestion there jnqaz.....made a lot of sense to me....

[belalegosi]

any update?

[Tarantula]

^^ I changed the crankshaft sensor yesterday also serviced injectors. Car running very free now so i'm not too sure if its cuz of the sensor or injector cleaning. I do know that i've eliminated the lazyness/buck that i used to get when pulling off from zero. That was a problem that i had since I bought the car and always thought it was the CVT tranny.

[wagonrunner]

Diagnostics never saw a problem with the injector pulse rate, or the sensors?
What diagnostics were used on this car?

[belalegosi]

Diagnostics never saw a problem with the injector pulse rate, or the sensors?
What diagnostics were used on this car?

how would diagnostics detect clogged injectors?
It would only read the digital command from the pcm/ecu and not the mechanical response of the injector.

Unless I'm behind on engine management advancements again

The laziness/buck you experienced was most likely fixed from cleaning the injectors. Injectors only open for really short periods of time (milli secs range) during idle. Clogged injectors or even improperly balanced injectors could cause what you're experiencing on take off.

The replacement crank sensor you use, was it new from dealership or new aftermarket brand?
Or used known good one?

To be honest, I usually just get my sensors from the junkyard. They are dog cheap/free and are usually OEM.... yes I'm cheap.

[wagonrunner]

how would diagnostics detect clogged injectors?
It would only read the digital command from the pcm/ecu and not the mechanical response of the injector.

Unless I'm behind on engine management advancements again

What i've been doing is using the O2 / Injector Pulse / and Duty Cycle. At idle, (1K WOT, 2K WOT, 3K WOT) when warm, sometimes a difference is noticed from they're clean.

Maybe I've been doing it wrong.

[belalegosi]

Ok I kinda see what you're getting at now.
I thought you meant the diagnostic readers would throw codes for partially clogged injectors.

If you have some background on the car I suppose you can infer problematic injectors from the o2 data. However on a factory narrowband sensor I would be skeptical.

On some (maybe most) cars the pcm/ecu disregards o2 sensor readings at WOT.
Idle and cruise is when o2 sensor values effect fueling.

An easier method to try to diagnose faulty injectors from the diagnostic data would be to monitor the fuel trims at idle. If the fuel trims are skewed then you maybe have a fault injector.

Anyways I digress.

[wagonrunner]

Ok I kinda see what you're getting at now.
I thought you meant the diagnostic readers would throw codes for partially clogged injectors.

ROFL. good one.

Idle and cruise is when o2 sensor values effect fueling.

Digress lil further. I'm not looking for effect of it (increasing pulses and DC stablish).
If the pulse width increases, DC similar with O2 similar at idle, and rev. would it be safe to say the injector is staying open longer to accomplish same work,. Hence maybe not as efficient or clean as it should be?

[belalegosi]

Digress lil further. I'm not looking for effect of it (increasing pulses and DC stablish).
If the pulse width increases, DC similar with O2 similar at idle, and rev. would it be safe to say the injector is staying open longer to accomplish same work,. Hence maybe not as efficient or clean as it should be?

Duty Cycle is a function of Injector Pulse Width and RPM.

If at constant rpm (assume idle) and constant o2 readings (lolz), the pulse width or duty cycle does increases then that could mean a number of things.
1. Inefficiency as you mentioned. Mechanical failure (problematic injectors, bad o2 sensor, lost/lowered cylinder compression).
2. Engine load increased (AC, Headlight, 8 12" Subwoofers, etc turned on)
3. Warm up, pcms are programmed to run richer during warm up.

I'm sure the list could go on as not all pcms use the same control algorithm.

[~Vēġó~]

The replacement crank sensor you use, was it new from dealership or new aftermarket brand?
Or used known good one?

The sensor was bought from the dealership...as in motorist....

The cost wasn't that bad (around $347)......which is still cheaper than the cost of repairing a blown plug (scan, plug and mechanic labour).

Keeping fingers crossed....after that I don't know what to tell him to do again, other than carrying the car and leaving it somewhere.....

[Tarantula]

So problem has resurfaced after 35 days. Cylinder 2 again. Going to clean the injector tips this time and see if this would help. It may be possible that one of the injectors is faulty..

[Tarantula]

Injector tips were clean, no major carbon buildup. Also they were spraying very good. Absolutely no problems.

I feel the next step would have to be the brain, I think I've exhausted all other options. Any extra advice???

[belalegosi]

huh.

At this point I guess changing the pcm would be your best bet

Another option is to make friend with someone with a similar tida.
Try swapping parts with each other until the problem transfer from one to the other.

[Tarantula]

huh.

At this point I guess changing the pcm would be your best bet

Another option is to make friend with someone with a similar tida.
Try swapping parts with each other until the problem transfer from one to the other.

LMAO at your suggestion but no. I think I write off Nissan for a good while. I done wid dat sheit.