Missing At Idle

[JVP]

Hye guys, i just changed my plugs to NGK's, gapped at 0.8.

when i had a major service done, they put in either 1.0 or 1.1.

now, i have noticed that it has a miss at idle, but not high up in the rev range, ie not 4500 and beyond.

now, i will be upgrading to a set of splitfires, but is there anything else that can cause this?

it never missed at all when i had the wrong plugs in, but it was backfiring a fair bit when the other plugs where in. the backfiring has faded away a bit, but now i have this miss when im sitting at traffic lights.

thanks for your help in advance

cheers

jarryd

[l0WRB]

  JVP-R32 said:

Hye guys, i just changed my plugs to NGK's, gapped at 0.8.

when i had a major service done, they put in either 1.0 or 1.1.

now, i have noticed that it has a miss at idle, but not high up in the rev range, ie not 4500 and beyond.

now, i will be upgrading to a set of splitfires, but is there anything else that can cause this?

it never missed at all when i had the wrong plugs in, but it was backfiring a fair bit when the other plugs where in. the backfiring has faded away a bit, but now i have this miss when im sitting at traffic lights.

thanks for your help in advance

cheers

jarryd

smaller ur gap more its gona miss fire on idle...i noticed mine really bad wen i regapped my .8 plugs down to .6 every morning i would start it up and it would sit there miss firing..so gay...

[JVP]

ok cool.

will the splitfires overcome this problem?

[Guest 40th-edition]

it may be your coils are just weak, but check your ignighter as well, may be stuffed.

also give your afm a check and clean if it needs it! may cause a rough idle

Edited January 15, 2007 by 40th-edition

[RB30X]

or open the plug gap up a bee's dick.

[JVP]

  40th-edition said:

it may be your coils are just weak, but check your ignighter as well, may be stuffed.

also give your afm a check and clean if it needs it! may cause a rough idle

ok cool. will clean AFM.

how do you check the ignitor?

if i buy splitfires, is it a waste, or precationary mod anyways?

thanks.

[r32matt]

Depending on how much you are going to mod your car and how stuffed your stock coils are. My coils started Popping at 4500revs but I fixed them with silicon. I also changed from Iridum 1.1mm Plugs to Copper 0.8mm. Im running 12psi and havent had a problem since. If i had extra money I would buy Spitfires but otherwise $600 can be spent on alot better things, such as fuel pump, boost controller, front/dump pipe, Intercooler, Injectors, Lighten Flywheel, Turbo.

[JVP]

already have most of the mods listed, but thanks for your help

[No Crust Racing]

My car has a very very very slight mis at idle but never ever misses anywhere else, I'm running Iritop plugs (factory gapped at .6) and splitfires. From what I've seen/heard the lower gap is the culprit and so long as it's not doing it anywhere else in the rev range you should be fine.

Splitfires will help depending on what boost/power levels you want as they give you (when coupled with better plugs) a nice strong spark.

[JVP]

ok cool thanks.

have been having a discussion with a mate, and he says if i change the coils the AFRs will be changed and will need a retune, is this true?

btw cars mods are full exhaust, fmic, bleed valve, bosh 040 pump and ecu remap.

and totally off topic, i have take off pretty much all of my wanky parts (bov and pod) and put stock items back on. does this also affect, or will it help? as in the AFRs.

thanks.

[No Crust Racing]

It's usually a good idea to tune again for new parts but that dpeends on what they are. Normally coils are put in to assist with higher boost levels so a re-tune is mandatory in your situation it shouldn't be necessary.

Removing the POD will have bugger all affect (see that various cars are making crazy power with stock airboxes and panels etc) but the BOV will have an effect as having a venting BOV upsets the amount of air in the system typically meaning the car will run rich as there's less air in the system at combustion time than there was when the calculations were made.

Anyone feel free to correct me Especially about the coils

Edited January 17, 2007 by ActionDan

[JVP]

UPDATE:

fitted my Splitfires last nite, there is still a bit of a miss at idle...

now i remember a while ago, i had a backfire issue with my car, and nissan played around with the timing, could this be related in anyway?

should i borrow an igniter to see if thats the problem?

thanks again

Jarryd

[Green_s13]

the miss at idle might be timing related with the lower gapped plugs, i would check that you car is at 15 degrees at idle if manual and 20 if auto.

also i recommend split fire coil packs i have them in my car and i haven't had any ignition related problems since

[Gazee]

Could it be the oxygen sensor thats not sending a signal making it run that bit more richer at cruise and idle? Cos mines missing @ idle aswell but i've got a bigger turbo making it run richer but i havn't tuned it as yet, when i tune it i think it will fix my problem...

[justin911]

mine did the same thing once i regapped my plugs to 0.6..

its better than missing when the car is moving so i try to ignore it

[JVP]

yeh thats true...

hmm might get the timing checked out, and check the 02 sensor..

thanks guys

[JVP]

UPDATE:

Cleaned AFM last nite...

problem still there....

should i get it re-tuned, and see how things are going, as in Timing, AFRs. etc?

thanks.

[Gazee]

  JVP-R32 said:

UPDATE:

Cleaned AFM last nite...

problem still there....

should i get it re-tuned, and see how things are going, as in Timing, AFRs. etc?

thanks.

Theres a way to check the oxy sensor... i think with a multimeter to see if its actually sending a signal to the ecu, probably check that its sending a signal before you get it retuned... seeing a tune will cost $450-$500 compared to an 1/2hr of your time to check the sensor and an odd $75 if its faulty...

[JVP]

hmm ok then.

ill get a mechanic mate to have a look at that, as i have nfi

thanks mate

[Taso84]

if it happened after u changed plugs, y dont u just change back to the original plugs?