Help! P0302 issue! Possible injector failure?

[ganque]

This is how bad it sounds on cold start... then took the camera to the inside so you guys can see what the AP reads

P0302 cold startup. Possible injector issue? - YouTube

P0302 cold startup. Possible injector issue? - YouTube

[btstarcher]

Raise your idle to 1000? LOL

Is that misfiring at idle? What are your plugs gapped at again? I know you've swapped coilpacks but what about plugs?

[Lex]

Car needs air fuel and spark. You covered spark by looking at plugs and swapping coils. The next would be air and fuel.

I would do a leakdown test just to make sure all is well and then look at the injector, seals and valves next.

Was VVT replaced?

[ganque]

Originally Posted by Lex Car needs air fuel and spark. You covered spark by looking at plugs and swapping coils. The next would be air and fuel. I would do a leakdown test just to make sure all is well and then look at the injector, seals and valves next. Was VVT replaced?

not yet. and I don't know anyone who has the tool to run the leakdown test

[Mazdazilla6]

Maybe it's just me but your fuel pressure seems high. Mine is only in the 400-500 psi area at idle.

About a month ago I had an issue where I kept getting a P0303 code but my idle fp was 200-300 psi and wot fp was down to 1600ish where it was normally 1800. I narrowed it down to it either being an injector issue or my relief valve.

I'm mostly sure it was my rv because fuel pressure dropped when the engine was off and warm. I never resolved the issue though because my fp returned to normal right before I was going to buy a replacement rv. I haven't had any issues since and there haven't been any codes.


Also here's what Mazda says about P0302

Screen Shot 2013-10-07 at 6.30.31 PM.png


If I was in your position I'd check all the wiring again to see if anything is amiss. If it all checks out then try something like this to check injectors.

Screen Shot 2013-10-07 at 6.40.14 PM.png

[Tokay444]

Nice. Mazda can control individual injectors with their scan tool.

[ganque]

Originally Posted by Mazdazilla6 Maybe it's just me but your fuel pressure seems high. Mine is only in the 400-500 psi area at idle. About a month ago I had an issue where I kept getting a P0303 code but my idle fp was 200-300 psi and wot fp was down to 1600ish where it was normally 1800. I narrowed it down to it either being an injector issue or my relief valve. I'm mostly sure it was my rv because fuel pressure dropped when the engine was off and warm. I never resolved the issue though because my fp returned to normal right before I was going to buy a replacement rv. I haven't had any issues since and there haven't been any codes. Also here's what Mazda says about P0302 Attachment 130314 If I was in your position I'd check all the wiring again to see if anything is amiss. If it all checks out then try something like this to check injectors. Attachment 130315

Fuel pressure under idle is normally around 440-450. Maybe the ECU is requesting more gas to the injectors which means is trying to send more fuel pressure.

:S

[silvapain]

Also as a quick check if you haven't already done it: take out the #2 coil and swap it for another cylinder. See if the misfire moves. Pull the plugs and see if #2 shows any damage; if not, clean them up and move the plug to a different cylinder. See if the misfire moves.

[btstarcher]

He swapped coils but not plugs yet....

[jack_hammer]

I'm going to speak for ganque in case it might move along the discussion, but he has already moved coils and replaced plugs.

Originally Posted by ganque Hey guys, sorry for bringing this thread back... I rather using this one since it might or might not be related... Another issue. P0302 constalty (Misfire on cyl #2 ), no matter how many times I delete it it pops up again... Symptoms: - Car hiccups randomly all the time on idle. Sounds worst on cold start. - Car runs extremely fine during regular driving, it actually spools up normally and feels quite strong. Some KR comes randomly. - AFRs are again oscillating between 14.4 and 15.2 on idle (so it´s leaning). - STFTs are kinda low on cold start but they eventually hit -0.16 on idle, STFT are good I think.. Things that have been done already: - Swapped coils between cyl #1 and #2 , issue remains on cyl 2. - Replaced the spark plugs. Had a brand new NGK 1 step colder and used an old Denso ITV24... same issue - Tried to do a compression test but my friend's tester gauge wasn't working properly.... but he is a very qualified mechanic and he said that the engine looked good.... So.. what do you guys think? I'm thinking on a bad injector? bad ECU harness wiring somewhere?

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[skeeter149]

im no expert at all, but in the vid i see your temp gauge is at the cold side. was the fp higher because the idle was higher to warm up the car? it came down a bit in the vid as i assume idle was settling with temp

[azazelthegreat]

Originally Posted by ganque not yet. and I don't know anyone who has the tool to run the leakdown test

Correct me if im wrong but cant you still half ass a leakdown test just to see if air comes out of places that it shouldn't
(hooking up a air compressor to cylinders etc)

id message daafisch, i remember him mentioning that his compression results werent to far apart or something, then it turned into a catastrophic mess

[Tokay444]

Same here. Compression is +/- 2psi.
Leak down 31% on cyl 3. Lol.

[Tokay444]

Are you consuming any oil homie?

[btstarcher]

I think he found a bad injector.

[jack_hammer]

Originally Posted by Tokay444 Same here. Compression is +/- 2psi. Leak down 31% on cyl 3. Lol.

That's got to be disconcerting to anyone who takes comfort in good compression numbers

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[El_Diablo]

A compression test just shows that the engine can compress the air and fuel where a leak down test will tell you if it can hold that pressure as well as where its bleeding off.

[Marcus]

Originally Posted by Tokay444 Are you consuming any oil homie?

Going to resurrect this shit b/c I'm throwing p0302s all day, rando p0300s and I'm on my 2nd qrt of oil between oil changes (not a full 2nd qrt tho, just up to 1.5L with 2200km's to go before next oil change).

What would this extra oil consumption mean besides something bad?

[Tokay444]

BESIDES something bad? Nothing. It's something bad.

[Marcus]

Originally Posted by Tokay444 BESIDES something bad? Nothing. It's something bad.

Balls.

[phecker410]

Another thread revival.
I'm displaying similar symptoms that are worsening recently (possibly colder weather)
My exception is that I have a warranty replacement motor from mazda with ~4000 miles on it sooo I'm assuming that the cylinders hold pressure just fine and that the valves are pretty clean.
Dealership mentioned that I might need injectors prior to swap but never replaced/mentioned it again.
Time to check injectors?

[Marcus]

Originally Posted by phecker410 Another thread revival. I'm displaying similar symptoms that are worsening recently (possibly colder weather) My exception is that I have a warranty replacement motor from mazda with ~4000 miles on it sooo I'm assuming that the cylinders hold pressure just fine and that the valves are pretty clean. Dealership mentioned that I might need injectors prior to swap but never replaced/mentioned it again. Time to check injectors?

What was the mileage on the injectors/old motor?

[phecker410]

68,xxx. I've had it looked at and I don't think it's anything to do with the injectors at this point but we'll see

[Marcus]

I'll re-reference my recent thread for some moar infos:

How I (seem to have) fixed my Early Speed6 Misfire Issue

Is yours the early model speed6 or post 2006.5?

[phecker410]

Thank you I just read through that.

And at risk of sounding like a brownie fuck-tard, I didn't know there was a difference with the ms6

[Marcus]

Originally Posted by phecker410 Thank you I just read through that. And at risk of sounding like a brownie fuck-tard, I didn't know there was a difference with the ms6

Easiest way to check besides your vehicle # would be pop your hood, find our cold pipe. If the stock oem plastic pipe is straight you have an early model speed6. If it's a bent elbow, you have a 2006.5+.

Mazda made a few changes mid production.

[ghost-rider]

sorry for posting in your old thread, but we didnt get the answer to these problems.

did you solve the startup misfire you posted years ago??

got the same issue and already changed coils, spark plugs and injectors and tested compression.

I got spark and suspect the already changed clean injector to bei failing.

but idk for sure if something bad is happening in this cylinder for some reason.

greets from germany

[MSMS3]

Originally Posted by ghost-rider sorry for posting in your old thread, but we didnt get the answer to these problems. did you solve the startup misfire you posted years ago?? got the same issue and already changed coils, spark plugs and injectors and tested compression. I got spark and suspect the already changed clean injector to bei failing. but idk for sure if something bad is happening in this cylinder for some reason. greets from germany

Which member are you attempting to respond to? You might want to try to send a PM to that person. Chances are pretty high that he is not following this thread all these years later.

[ghost-rider]

i tried before, but dont have permission with only 1 post on my account.

Would you mind, send a pm to him for me and help some buddy from overseas

[Vansquish]

Originally Posted by ghost-rider i tried before, but dont have permission with only 1 post on my account. Would you mind, send a pm to him for me and help some buddy from overseas

We still need to know WHO you are trying to contact? A lot of people have responded to this thread over the years.

As far as diagnosing your problem, have you tested the harness to see if there are any weaknesses? Specifically, have you checked the ignition harness to make sure that there are no broken/bent pins that would cause cylinder 2 to get weak or no spark?

Similarly, have you checked the injector harness for the same sorts of faults?

[ghost-rider]

youre right sir, i saw the video on top of this page from "ganque".
Already saw a lot of threads an contacted a lot of people since over a year with this problem, and never got an advice which solved this problem, just the started threads...
you know this problem on the internet for sure.

Hopefully its okay to use this thread for my personal problem.
Otherwise is will start a new one.

I tried new and old coils and spark plugs, they all worked well and got strong spark.
Checked compression on cold engine (not optimal, i know) tested all cylinders with 135-140 psi.

Only on cylinder 2 i dont see any response if i unplug the coil, so i would think on injectors, but these got cleaned an checked recently.

Curious the misfire only persists in idle oder very low rpm, if i push on the pedal it seems to work.

I will check the injector harness next and clean the plugs, as i lubed the o-ring with engine oil there could be a culprit. Even when i cleaned with brake clean after.

[Vansquish]

What was the gap on the spark plugs that you installed?

[ghost-rider]

Originally Posted by Vansquish What was the gap on the spark plugs that you installed?

installed the genpu Plugs ILTR6A-7G, and tested also the old 8G Plugs which were only 2 years old. The Coils were also NGK, new ones mod. 42899.

Also changed Intake Manifold and Throttle Body Gasket, aswell as Header and both Turbogaskets as i installed a new Turbocharger at this point.

I got an primary EGR Delete and added also new Gaskets to be sure and threadsealant on the Plug in the Intake Manifold.

Will check the harness, if some of the lubrication oil got inside the plugs an clean them with contactspray.


You can see the jumping stft in the logfile

[Vansquish]

You didn't answer the question. What was the gap in the spark plugs? Did you check to make sure that they were in spec between 0.024 and 0.027 inches (about 0.61mm - 0.68mm)?

[MSMS3]

Not to pile on but proper plug gap is critical on this particular engine. Vanquish is right to ask you twice.

They need to be tighter than most sets come from the factory and never trust the factory to get them right, anyway. The fine wire iridium tip is very easily damaged in gapping. Do not use a gapping tool that scrapes that tip.

I don't know if that solves your problem, but it will eliminate one variable.

[ghost-rider]

yes sure, i gapped them just a little bit more than they were stock to 0.65, the old ones were 0.8 as spec. No gapping on these ones was needed to spec.

Do you think that some engine oil could make its way into the injector plug also because of oiling the o-ring?


i dont get you wrong guys, im familiar with this platform since 6 years now, before i had a 3 MPS and for over 2 years the 6 now

[ghost-rider]

i took the intake manifold off today an cleaned the harness connectors and injector connectors with electric cleaner, now i get a response from cylinder 2 when i unclip the coil.

Not as much noticable as when i took the other cylinders off but still hearable from the exhaust. With the cylinder 2 unclipped i get much more misfires at idle.

Hold the RPM at 2000 for expample and get no misfires, mysteriously.

Sure without the Intake on the car, the MAF was not on the car at this moment, it runs in limp mode.

How about the o2?? That would be my last idea, as the ECU just regulates with the o2 and throttle?

[ghost-rider]

no one looking at the video or log yet??