Misfire

[mazdafamiliamx3]

Hi everyone, new to the forums, i have a misfire in my v6. Im using the pictures from this link as a reference http://www.mx-3.com/phpBB3/viewtopic.php?f=23&t=62510.

When i pulled the spark plugs, cylinder one according to the firing order picture was running rich and 4 and 6 are running lean. I did a compression test to make sure everything was cool. everything was 180 BUT the 4th one which was like 150.. I made the mistake of putting bosch spark plugs (won't ever do that again and read on here after the fact they are bad for our cars) and it and that blew a hole in my exhaust from all the backfire. Cap, rotor, ignition coil, wires and plugs are new (plugs are NGK and gapped). So im at a loss. Injector maybe? if so im defintely dont wanna to pay the money to do that. Am i better off just swapping the motor? is it my dizzy?

[mikeinaus]

o2 sensors?

[mazdafamiliamx3]

o2 sensors are new

[mikeinaus]

are you getting any cel codes? have you checked your timing? when you replaced your ignition coil, rotor and cap you may have moved the position of the disty throwing your timing off. your compression numbers seem pretty solid so your motor is probably in pretty good shape. you could try another disty (if you can borrow a known good one, or find a cheap one used), but they tend to cause problems when there at running temp when there about to die.

common disty problems are:
misfiring when warm
stalling and/or not starting when warm
lack of power/bad fuel milage
and many weird random problems i can remember at this point in time...

[newdriver92]

Hi everyone, new to the forums, i have a misfire in my v6. Im using the pictures from this link as a reference http://www.mx-3.com/phpBB3/viewtopic.php?f=23&t=62510.

When i pulled the spark plugs, cylinder one according to the firing order picture was running rich and 4 and 6 are running lean. I did a compression test to make sure everything was cool. everything was 180 BUT the 4th one which was like 150.. I made the mistake of putting bosch spark plugs (won't ever do that again and read on here after the fact they are bad for our cars) and it and that blew a hole in my exhaust from all the backfire. Cap, rotor, ignition coil, wires and plugs are new (plugs are NGK and gapped). So im at a loss. Injector maybe? if so im defintely dont wanna to pay the money to do that. Am i better off just swapping the motor? is it my dizzy?

heyy ya i've been having the same issues as u
is it more notice able when its warm and in drive when u have your foot on the brake

[mazdafamiliamx3]

yea it gets worse once the car is warm. I have to rev the car very high in 1st gear in order to get the car going and so it doesn't bog down and cut off. It use to be a intermittent misfire. Like i would be on the highway and it'll run normal for a bit and then misfire and then continue to misfire. After doing some more searching on here it says that the distributors are prone to going bad in these cars?

[newdriver92]

yess and it could be timming, and even fuel. whats your cold idle at

[mazdafamiliamx3]

yess and it could be timming, and even fuel. whats your cold idle at

when it starts up it idles at like 1300-1500, then drops down to like 700-800 when warm. when engaged it rises slightly to like 1k.

[newdriver92]

ok is the mis more noticeable in drive with the brake applied and fully stopped

[newdriver92]

if its a fuel issue it could be the: pump, filter, fuel pressure reg, injectors, or even pressure
ignition could be: disty, ecu, timing etc......
umm maybe vacum leak, or O2 sensor
its hard to say u should get the timing up to spec if not on soec

[mazdafamiliamx3]

ok is the mis more noticeable in drive with the brake applied and fully stopped

not sure exactly what your saying there but its most noticeable in drive and i dont keep my foot on the brake when im at a stop because its stick...

[newdriver92]

ok is the mis more noticeable in drive with the brake applied and fully stopped

not sure exactly what your saying there but its most noticeable in drive and i dont keep my foot on the brake when im at a stop because its stick...

oh lol ok i have a auto

[mikeinaus]

if it happens more when its warm its most likely the disty. like youve found our cars have a defect in the design of the distributor causing it to overheat and fail over time. they can be pretty expensive to buy new so used is usually the best way to go.

or you may be able to do the external H.E.I. mod, but ill leave it up to you to find the guide, and to find out whether or not yours is applicable.

like the other guy said it could also be a vacuum leak. play around with your hoses and see if you can find anything. if not see if you know anyone with an mx3 you could borrow the disty from and try it out.

[Daninski]

Use the search here? With misfiring there is no clear cut answer, could be anything from a bad spark plug to faulty injectors. I've posted some very informative reading on this issue so type in misfires and possible my name (daninski) and you should get 2-3 different posts. Good luck.

[mazdafamiliamx3]

Use the search here? With misfiring there is no clear cut answer, could be anything from a bad spark plug to faulty injectors. I've posted some very informative reading on this issue so type in misfires and possible my name (daninski) and you should get 2-3 different posts. Good luck.

well i took a spark plug reader to one of the cylinders and it was firing much weaker than the others so im going to try to get a disty and see if that is that issue or not.