08 MPS 3 Misfiring

[CHMPS]

Hi Guys,

Cold start was really rough for me today and didn't get much better with the car running like a dog, misfiring I think through gears and rev range. Is quite cold here at the moment, (5-9 deg C). No error codes on my accessport. Can anyone help diagnose? Mods as per signature. Part throttle log attached (3rd gear), would a WOT log be more helpful?

When I get a chance I will be cleaning MAF sensor, checking plugs, and possibly stretching coil pack springs, checking for any leaks, Anything else to add to this?

Regards

[SarcasticOne]

I'd check spark plugs... If they're one step colder they'll struggle more in the cold...

WOT logs (or a MAF cal) could be useful as well... Cause your AFR's are all over the place in that log, and you had massive knock to begin with...

Know mine struggles for first 2-3 minutes with one step colder plugs and e20 mix in the same temps...

[CHMPS]

Just cleaned the maf sensor, found that the o-ring is buggered so that's a possibility, will have to order a new one ASAP. Clamped it down good and took this maf cal - no change still running badly.

Will proceed to check plugs etc.

[CHMPS]

Pulled the plugs, all seem pretty normal to me, one seemed to be gapped far too small so another possibility! Wondering if I should just put a brand new set I have sitting here in?




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[SarcasticOne]

http://ngksparkplugs.com/tech_suppor...qs/faqread.asp

[CHMPS]

I'm interpreting them as light grey = normal, but I am colourblind haha,


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[Lachlan]

When you cleaned your maf, did you take the intake apart or just pull the maf off? Iv seen several corksport intakes where the air straightener comes loose and falls into the filter, randomly blocking flow and causing erratic crap to happen.
Also check the gap of all your plugs, its critical on these engines (and plugs don't always come gapped properly when you buy them)

[CHMPS]

Hey mate, have actually taken the air straightener out as corksport said it's not needed on the Gen 1. Yea i might put it all back together with the regapped plugs and see how it runs.

[Lachlan]

Mmmk. Every good intake, including corksport and stock have straighteners for good reason, so i don't buy that. Hopefully plugs fix it though

[CHMPS]

More power on the gen 1 without it! Any ideas for a substitute maf o-ring? Am waiting on one from mazda

[Lachlan]

Seems like a pretty backyard ghetto way of adding a tiny bit of (no doubt unnoticeable) power vs just using a larger intake and proper tune. If Mazda are taking ages, you can get maf o-rings from edge in the us (maybe see if someone near you is ordering anything from them soon?). One of these solutions might work too http://www.ozmpsclub.com/forum/intak...ke-o-ring.html

[CHMPS]

Still no luck, have got the new o-ring. Gapped plugs at .026". Have been told to check my grounds, is this visual or with multimeter, how do I do this?


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[MPS2NV]

Anychance you have cleaned the map sensor?

[CHMPS]

Yea cleaned the maf sensor when I regapped the plugs, wasn't really dirty anyway. Am thinking I possibly have a cracked plug insulator as I didn't really check that. Just need a chance to put new plugs in


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[MPS2NV]

MAP, have had recent case of rough and low idle, on a hunch I remove the MAP (located in the manifold) it was full of egr/oil crust.

[CHMPS]

Am replacing 2 coils tomorrow, which is the most likely to be bad? Try the other two if that doesn't work. Bought a grounding kit for good measure.

The map is in the intake manifold? Big job?

Ray has also said it may be bad injectors. But to me it feels like a coil, so hopefully the simplest explanation will be the right one!


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[Lachlan]

Whats your misfire code? Should be referenced to a particular cylinder, and if so you can move the coils around and see if the misfire follows the coil. If so, replace, if not then its something else.

Also, you are VIP so you can download the service manual and it will tell you how to switch the map. Or just read http://www.mazdaspeedforums.org/foru...-sensor-45006/

[CHMPS]

Don't have any codes! It is a stutter /hesitation throughout the rev range. No luck with the 2 new coils in cylinders 1 and 2. Will have a look at the map, cheers


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[SarcasticOne]

[SarcasticOne]

Looks like yours weren't worn evenly...