right guys i still got the miss fire i have changed the plugs leads dizzy car roary arm petrol filter oil oil filter cant find any split pipes at all but its fine on idle and when u boost up just driveing normal the missfire is there wud it be an injector now thats the only thing left i can think of everythink else has been changed now so can anyone help plz

 

could be head gasket could be the fuel pump powering down had that on mine before could be actuator or try unpluging the amal valve and see if that helps


justin

 

compression check is your next step

 

possible your fuel enrichment for on boost is not working but you'd need a afr to see that

 

well its had a new head gasget and since i put it all bk togher its been the same the plugs are going black put an amul valve on it and nothink

 

coil? ive had the same problem before when higher up the revs but ok for normal driving..

 

If your plug's are getting black then you have a fuel/air mixture problem mate best to have that looked at by someone who knows what there doing.

 

Ant you have the point straight away. After having an MFi car in pieces or once you have changed anything you will need to get it setup to make sure everything is how it should be.

 

i had a very similar problem 2days ago changed head gasket an started up idled fine but wouldnt rev up missing like fook changed the same as you plugs,leads,cap,rotor.
had it on C.o meter an nothing worked! it turned out to be 2 sensors on the inlet the aux air valve an the water temp sender (i think thats what its called) underneath the inlet an it ran perfect after it so i cant stress enough make sur there on!!!!!!!!!!!!

 

like studabear said do a compression check, then start looking at fuel pumps etc. could be piston rings, valves not seating, headgasket, anything like that! eliminate as many possible causes as you can

 

IS this missfire evident at idle, or when driving or both? MFI systems are very sensitive to air leaks, more so at idle for obvious reasons. It would have to be some pretty serious overfuelling for it to cause a missfire.

As for the comments about the sensors, the auxiliary air device is merely a means of controlling the engines idle when cold, if it was faulty you would see abnormally high idle speeds when hot. The coolant temp sensor would almost certainly make it a nightmare to start from cold.

As someone else said, a compression test is a good place to go now. And remember also, air leaks can be ANYWHERE on the engine itself (as its connected into the breather system), and that they are not just limited to the intake pipes. The brake servo leaking air is another favourite that is overlooked.

 

Check it step-by-step. Especially the easy things. Ignition timing? Should be different when revving the engine. Broken ESC-unit might cause the ignition timing to stay at idle position. Then check for air leaks, fuelling and so on...

 

what i ment by the aux air valve an temp sender i had the plugs the wrong way round an caused similar problems.

would start fine an idle from stone cold but would miss wen revved an it turned out to be the two plugs on the wrong way round swapped them an its been fine since.

its a two second job an if it dont work swap them back.

but definatly check for compression an air leaks..

 

wot colour are the qux air valve plug and the water temp sender plug

 

Aux air valve - BLACK
Water temp - YELLOW

Id still say you have a fuel problem mate if your plugs are getting black quick id get that checked after doing a compression test as that cost's nothing to do a compression test

 

antony215
Aux air valve - BLACK
Water temp - YELLOW

as antony said with the colours also my plugs were gettin soaked in fuel an black as night when on the c.o meter at idle i had it to about 2.8 a slight touch to richen it an it would shoot up to 6-7 changed the two plugs round while car was idlein an it cut out started back up an revved fine a few little adjustments on the c.o an idle screw an it was fine.

let me know how you get off with plugs..

 

all above is good advice...

couple things off me head...

next to the coils there is a little black square rectangle box that is in the wiring this can go sometime which is why people hard wire them straight through.

check the voltage on the fuel pump underload.
coil
gapped plugs

 

Coils? Black box? Are you talking about EFI by any chance, thats what it sounds like to me?

 

the engine is mfi i dontknow if it makes any diffrents but the yellow plug on bk of engine was broke and i cud not find a yellow one anywhere so i cut a brown one off a car at scrap yard and wired it where the yellow one goes it fits on ok but wud this be anythink to do with it

 

see i took it for a drive arfter swapping the meetring unit and the miss fire went then when i put me foot down it come bk thats the only time it cleared tho

 

i have done conpreshion check and its all good i started the car this morning and run fine with no missfire but only lasted about 20sec then come bk anyone know

 

did you swap the two plugs that i said round? because it sound exactly like the problem i had from the startin fine an idle but then miss.

dnt worry about the two colours for a min cos as you sed 1s a diffrent colour now.

there's a plug on a sensor underneath the inlet an the the plug on the aux air valve which is a circle silver thing with two pipes for vaccum one from top of inlet an the other goes to bottom of throttle body. they are the two i swapped an i worked fine

i went through the proccess of changing everything too metering head an all ignition parts an nothin worked so i just thought id give the sensors a go an i did it while the engine was runnin took the two off an as i plugged em back in it cut out started it back up an i ran great.

but if you have tried it an nothing them im stumpped mate you'll have to get a proffesional to take a look. good luck anyway i know how much of a pain they can be.lol

 

right tryed them 2 wires and nothink i took the injectors out today and one of the rubbers on it is all broke wud this cause the miss fire

 

i think it might if its drawing air through

 

at least youve ruled wiring out now.lol!

i would have thought id would be missing all the time if it was the seal an idle terrible like they do when a boost pipe or similar is split and suckin air but change it to make sure.

 

right i took the injectors out today see if thay was spraying and thay was fine but one of the rubbers on the top was broke i got a 2nd hand injector and put it in with a good rubber and it fired up no miss fire took it up the road was fine put me foot down miss fire come back

 

So is it still miss firing or only when you put your foot down

 

its still like when u rev and and mid way its still there but weird how it went then come back