misfire,hesitation,faulter?????

by **stag76** » Tue, 17 Apr 2012 9:53 +0000

hi lads,more drama with my 90 mx5.

3nights ago i was driving my mx5 hard,racing a boxter off lights,messing and not winning.

i noted later that night a slights miss when pulling away,only up to 2000rpm and after that fine.

the next day started car and it a bit worse under acceleration in 1st and 2nd up to 2000rpm and after that fine.

last night,started and she the same,but after around 10min driving a faulter?miss throught the rev range,as if it is running out of petrol.

if you accelerate like normal,it misses and act up,but if i accelerate very gentaly it is fine??

when im doing 60mph and floor it it just misses,if im doing 60mph and i throttle gentaly she grand no hesitation.

so bad now i have lumpy idle,and if i rev it i get the miss straight off.

it has to be fuel or spark.

its not head gasket,or any heavy mechanical problem.

so what do you think??? i havnt checked anything yet.

could it be leads/coil pack/fuel pump/sensor.

any ideas,is this a comman fault,is there a diagnostics plug on these,are there fault codes i can read if there is a plug.

car not drivable,so need help :shock:

thanks,any ideas will help alot

jay

by **mx5ash** » Tue, 17 Apr 2012 10:15 +0000

Id go with leads first then coil pack.

by **leamyj** » Tue, 17 Apr 2012 10:16 +0000

Hmm, if your leads and ignition are fine then you may have fuel starvation?? Being a '90 mk1, and if you've got the original fuel filter, it's now 22 years old. I'm not sure how you'd diagnose this for sure, short of by-passing the filter with CLEAN fuel and see how she runs. The filter is located near the rear driver's side wheel behind some protective panelling..best have a mechanic look if you're not that way inclined..petrol is not to be messed around with.

John

by **stag76** » Tue, 17 Apr 2012 10:26 +0000

hi lads,thanks for the ideas.

yes id say its what you have mentioned,from what i here the leads are a week point,could be arking under load,or coil pack breaking down.

fuel starvation could also be it,ill change the filter anyway i think.

ow im well handy with the tools,ive been working on old triumphs man and boy :lol:

thanks again,anymore ideas be great.

ill keep you posted,il have a fiddle 2moro.

anybody have good leads and pack i could try before i go to expence of buying new???

can trvel a bit,im in west dublin,be good to meet the lads also.

thanks jay

by **sidewaysreilly** » Tue, 17 Apr 2012 11:11 +0000

think i have a few spare to diagnose . Near drogheda and will be havin a tech day next saturday if you can make it down.

by **stag76** » Tue, 17 Apr 2012 11:21 +0000

hi side ways,thats great,yes id like to go to a tech day.

yea i can try and drive her up to you.

what time is the tec day on at ??

im free on sat so il head up.

ill txt or ring you if you can give me your number.

jason 086 895 30 80.

thanks jay

by **sidewaysreilly** » Tue, 17 Apr 2012 11:24 +0000

no bother, ill post on the tech day post already on here.

Sean, 0877922285

by **stag76** » Wed, 18 Apr 2012 11:15 +0000

hi lads,got my mx5 sorted today.

i changed the plugs for new ones this morning,no change,i then changed the fuel filter,no change.

well i limped her out to robert in autocheck,he had a set of leads,popped them on,and after a test drive,fixed

.

so thanks to all who offered suggestions.

still intrested in the tech day sideways

jay

by **sidewaysreilly** » Wed, 18 Apr 2012 11:21 +0000

yeah sure come on down and you'll learn something lad.