Can anybody give me any reason why my car could be missfiring?

 

Im getting very bad missfiring at high rpm and a noticable missfire at low/idle.

 

All the injectors are firing and connections seem ok

All Coilpacks seem to be working and the connections are ok on all but one.

 

This prolem is driving me mad and i need any help you guys can throw out.

 

Note to john300zx, my idle problem has reappeared!

its getting rediculas now, i had no issues at all untill i got a dodgy idle one day and its not gone back since!

Just been out in the car and it took ages to start, it just didnt want too! it kept starting and stalling for ages before i could get it to work!

 

And this might sound stupid but do you think it could be related that my drivers door keeps ****ing shocking me!

Think you really need to hook it up to ConZult. Could be something to do with your TPS setting if you've only noticed this after an idle fault.

 

Have you checked the ECU for codes?

yep several times, and i get a code 55 and o2 sensors say all good too

Have you tried another MAF?

no but its not the maf because i can go all the way to the redline and im getting missfiring at idle too.

 

Plus it happens in all weather and its hidden by a huge oil cooler.

pete sounds like you have inherited the same problem i have got exactly....

 

now between you and me maybe we can come up with a solution ???

 

my car goes well sometimes but sometimes it clearly starts to missfire once warmed up like once its past the autochoke stage on other cars toyotas seem to rev high till the choke goes off then they calm down .. well this zx seems to run smoothly in the first 5 mins of running once slightly warm it starts to missfire ..

after undergoing all suggestions from here i have changed plugs coilpacks injector plugs coilpack plugs have tried timing also no leaks.. tps is set using voltage correctly det sensor is bypassed to rule that out ...still i have same intermittent problem ..

the more i use my common the more i think this is something as simple as a stray spark somewhere i think znut meantioned it in another post ... so try looking for a spark in the night ... when you find a fix if you do let me know and ill do the same back ..

maybe somebody could design some heat resistant non conductive sleeves to put in the hole where coilpacks go just a half mill thick or so to stop stray sparks..

the stray sparks or 'arching' explained by znut would only become aparent on the coilpacks themselves, if one is split or has even a hairline fracture in the rubber (usually the tip) then you could get a stray spark.

The spark however doesnt have anywhere else to go inside the sparkplug resovouir except the spark plug, unless the resovouir is cracked or covered in shite.

 

I have checked mine today and they all seem in great nick.

Ive ordered new plugs and pcv's today to stop all that oil in the intake but to be honest, im at a blank

ok can a safly say that if we where using common sense here a vacuum leak could not cause a car to missfire...

what i mean is one set of problems are surely electrical as in a missfire and a vacuum leak surley would just cause loss of power however it would not stop the spark plugs sparking ..

pete i honestly think the conzult thing would be a better buy im going looking for it or datscan it would save everybody on here alot of problems and money .. if i buy one i will flog you a copy as you can get the dongle from china for 40 quid to plug it into your lappy .. well basically it would save us both a shit load of trouble and give us a head start

they're about £400 i think, and i think you need a licence for the soltware

iff you can get it over to the wirral at the w/end ile have a gander and plug my conzult in;) and like i say to all my visitors i smoke lambert&buttler in units of 20:)

Znut, your a star, but i cannot get there this weekend. and if you smoked marlboro that would be better as my ladies dad has tons :)

 

Ill get back to you

Znut, your a star, but i cannot get there this weekend. and if you smoked marlboro that would be better as my ladies dad has tons :)

 

Ill get back to you

 

just stay away this week..i have germs:smash:

pete sounds like you have inherited the same problem i have got exactly....

 

now between you and me maybe we can come up with a solution ???

 

my car goes well sometimes but sometimes it clearly starts to missfire once warmed up like once its past the autochoke stage on other cars toyotas seem to rev high till the choke goes off then they calm down .. well this zx seems to run smoothly in the first 5 mins of running once slightly warm it starts to missfire ..

after undergoing all suggestions from here i have changed plugs coilpacks injector plugs coilpack plugs have tried timing also no leaks.. tps is set using voltage correctly det sensor is bypassed to rule that out ...still i have same intermittent problem ..

the more i use my common the more i think this is something as simple as a stray spark somewhere i think znut meantioned it in another post ... so try looking for a spark in the night ... when you find a fix if you do let me know and ill do the same back ..

maybe somebody could design some heat resistant non conductive sleeves to put in the hole where coilpacks go just a half mill thick or so to stop stray sparks..

 

Since you sold me your lame donkey of a 300ZX saying that your mechanic says it only needs fuel injector connectors to cure misfire,you refuse to take my calls.How interesting is it to actually find you on this site telling the truth,it would have been nice if you had told me that you had bypassed the det sensor. I would suggest no one buys a car from this con merchant. He lives in Newcastle and not Ireland as is stated in his profile.You sad little man:nono:

I hope you dont mean me

I hope you dont mean me

 

Did you find what caused your miss fire in the end

pete sounds like you have inherited the same problem i have got exactly....

 

now between you and me maybe we can come up with a solution ???

 

my car goes well sometimes but sometimes it clearly starts to missfire once warmed up like once its past the autochoke stage on other cars toyotas seem to rev high till the choke goes off then they calm down .. well this zx seems to run smoothly in the first 5 mins of running once slightly warm it starts to missfire ..

after undergoing all suggestions from here i have changed plugs coilpacks injector plugs coilpack plugs have tried timing also no leaks.. tps is set using voltage correctly det sensor is bypassed to rule that out ...still i have same intermittent problem ..

the more i use my common the more i think this is something as simple as a stray spark somewhere i think znut meantioned it in another post ... so try looking for a spark in the night ... when you find a fix if you do let me know and ill do the same back ..

maybe somebody could design some heat resistant non conductive sleeves to put in the hole where coilpacks go just a half mill thick or so to stop stray sparks..

 

 

If its missfiring after warmed up i would suggest you check the PTU, fit a known good ptu and see if it solves the problem.

These usually start playing up once warm. You could also try dabbing it with a wet cold cloth to cool it down see if it stops missfiring.

If its missfiring after warmed up i would suggest you check the PTU, fit a known good ptu and see if it solves the problem.

These usually start playing up once warm. You could also try dabbing it with a wet cold cloth to cool it down see if it stops missfiring.

 

Think it's a post from last year jimmy

Think it's a post from last year jimmy

 

Yeah i know but this will help when peeps do a search for "missfire" and need advice. As this is prob the latest missfire thread atm....

Always Keep it simple mate.

Its normally A connection problem. with the injectors if there green and crappy on the connectors then you need to replace the plugs and chemically clean the terminals on the injectors.

Also look at ptu connections for intermittant contact failures.

and coils and Always remember to check or replace the spark plugs.

 

in my time its nearly always these options ..

good luck.

but remember keep it simple first!

Yeah i know but this will help when peeps do a search for "missfire" and need advice. As this is prob the latest missfire thread atm....

 

Cool, fair enough! :p

Yeah I had a glowshift 'Air/Fuel' ratio gauge fitted and it was giving a duff signal to the ECU but i had taken it zworld a few days later and they sorted it.

Off topic. But pete those wheels are stunning :cool:

Off topic. But pete those wheels are stunning :cool:

 

the kind of off topic that i like :smash: