occassional stutter

[mrt72]

hi guys, need to pick those brains of yours cos im lost on this one now.
evo 4 mods are 2.5" downpipe with straight through decat going into a 3" hks back box, apexi induction and baileys bov.
had issues with it since i got the car, having the odd hickup every so often, can be sat ticking over and every few minutes or so it'll miss a beat.
some times its worse and sometimes it hardly does it, but the problem is it also happens when driving too, so if ya booting it and it does it, it almost puts ya through the windscreen.
with this comes a rather eratic tick over too, i'm guessing the problem is related,
one minute it ticks over at 750 and then 800 or 850 or 900 and upto 950.
i've cleaned the maf, ive replaced the cam sensor, i've set the throttle position sensor, i've cleaned the throttle body thoughly.
what next?

 

[mike evo iv]

have you checked the idle screw hasnt been screwed out to much and checked the idle servo. had i little problem with my evo4 keeped cuting out so adjusted the idle screw it sometime idled fine then other times was allover the place. i pulled the big connection block off on the side of the throttle body wiped the pins clean the rest the ecu by diconnecting the battery for 10 mins and then running the car with evey thing on for 10mins turned it on and off a few time it worked fine since as for puting you through the wind screen mate not to sure lol. the only time i felt something like that in mine it was when it hadent been delimited and i hitt 180kph that was like hitting a wall, (is yours delimited) may it could be speedo sensor not reading wright. thats just a gues mate. im sure more will reply soon matey. hope thing iv my help mate

 

[mike evo iv]

have you checked the idle screw hasnt been screwed out to much and checked the idle servo. had i little problem with my evo4 keeped cuting out so adjusted the idle screw it sometime idled fine then other times was allover the place. i pulled the big connection block off on the side of the throttle body wiped the pins clean the rest the ecu by diconnecting the battery for 10 mins and then running the car with evey thing on for 10mins turned it on and off a few time it worked fine since as for puting you through the wind screen mate not to sure lol. the only time i felt something like that in mine it was when it hadent been delimited and i hitt 180kph that was like hitting a wall, (is yours delimited) may it could be speedo sensor not reading wright. thats just a gues mate. im sure more will reply soon matey. hope thing iv my help mate

i mean reset the ecu

 

[mike evo iv]

sorry about the spelling typing to fast lol the last bit ment hope something iv said may help lol

 

[jasinuk34]

have you tested the coil packs?

 

[mrt72]

no not tested them properly, i've had mut monitor on it and that said they was ok.
would the coilpack give such an infrequent misfire?
and as for the limiter theory, its just like that but happens as and when it pleases, but no ecu faults showing.
its something stupid i know it is, just remembered it aslo occurs when you drop the bonnet down.
checked everywhere for a loose connection and nothing yet, plan b is change the maf i think

 

[B6lee]

Plugs maybe the issue. Have you replaced them and or gapped them ?

 

[mrt72]

i've not replaced them yet lee but i've had em out and cleaned and gapped them as they looked pretty new.
plugs wouldn't explain the stutter when bonnet dropped though would it?
tried an idle reset a couple of times now with no joy.
and for the idle screw mike, which screw do you mean? theres the idle mixture screw on the throttle body and one on the throttle leaver?

 

[mike evo iv]

the screw on the top next to the trottle position sensore. mine was tured out to much made the car run rich and reves where all over the shop. if you do try i winding it back in (clockwise) and it hasnt worked just count how many turns you gave it and put it back to where it was. now you said it my car used sudderd when i knock the maff sensore when i was having problems with mine and i thought that the maff was faulty on mine but dont be to hasty with changing the maff. have you had the idle servo out and give it a proper clean what your describing happened with mine. tuck the idle servo out and cleaned it up its on the side of the throttle body with with 3 screws holding it in. i think its just as you said something so simple. i tuck mine to mitshubishi for a engine scan to try and find the promble and they couldnt fine anything wrong. if you do find its the idle servo you can fit the fto idle servo in your evo plus its cheaper.

 

[mrt72]

i've had the complete throttle body off mike and cleaned every little bit of it cos it was well oiled up.
i thought it was that too and it was a no no, also tried the throttle mixture in all positions and still its all over the place.
i know its a common thing with them to not be stable but its a little too eratic for my liking.

 

[mike evo iv]

i no what you mean mate by being eratic mine done my head in i put up with it for six months, it has to be some sensor do you no any one with another evo that you could just swap a few sensors with just to see if you can find the problem, you might just have to spend the odd coin or two to slove this one. sorry i cant be much more help il ask my mate for you hes on the fourm to hasnt been on for a bit but will ask as hes a bit more clued with problem solving than me with faults

 

[mrt72]

nice one cheers mike.
all help is apprciated mate.

 

[mike evo iv]

my mate said he will have a look at your thread to night when he gets 5mins, hes jay2k6. if he doesnt and he forgets coz he is a bit of a gimp lol just go into members list and message him. he will get back intouch with

 

[jay2k6]

I know you checked your plugs and cleaned them but have you tested them? Some times under undue stress they won't fire correct had similer problem with mine, when really pushing it, it would lurch and nearly send me through the windscreen lol remember you've only got two coil packs so if a plug is not working as it should it will give you problems, just test if they are sparking correct mate, hope this helps you out dude

 

[mrt72]

i'll stick a new set in and see if that changes it.
cheers guys much appreciated.
is there a standard setting for this mixture screw and the throttle stop, i've gone throught the manual and all it says is ".45 feeler guage between sas and throttle leaver and then turn the screw 1 turn", but it doesn't say what screw or what part it classes as the sas.
in the olden days it was usually 1 1/4 turns to standard, is it still the same?

 

[sponners]

i'll stick a new set in and see if that changes it.
cheers guys much appreciated.
is there a standard setting for this mixture screw and the throttle stop, i've gone throught the manual and all it says is ".45 feeler guage between sas and throttle leaver and then turn the screw 1 turn", but it doesn't say what screw or what part it classes as the sas.
in the olden days it was usually 1 1/4 turns to standard, is it still the same?

(no mixture screw, your thinking old carburetter days)

to adjust the biss screw for the throttle plate you need to take it to a mitsi dealer or find someone with evoscan/laptop to park the stepper motor - then you set the rpm using the screw.

 

[evo arm's m7960]

hi just out of interest have you ever changes the fuel filter ?? had a simular problem on a old uno turbo years back .
it went like stink then one day every time you hit boost it was like hitting a wall , changed loads of sh t on it untill one day after about a month i changed the filter and problem solved . you could have a fuel flow/ pressure problem maybe . ???

 

[mike evo iv]

you can alter the reves with the idle screw next to the throttle position sensor mines nearly screwed all the way in but other cars might be different. but first give it a service i would try all fillters and new plugs to start mate it doesnt cost to that much you can buy a service kit from camskills uk for a about £45.

 

[fq-craigus]

My revs change when bonnet is dropped too, strange. I would blame plugs or cp easy to swap off another car if one is handy I did this today thanks to fazzhead off here, unfortunatly didn't give me the answer I was looking for

 

[mike evo iv]

dont mess to much with the screw to much as your car can start to run rich, i found that with mine on a dyno run mine run extreamly rich had to turn it back to where it was when i got home oops:wtf: