got a Grand vitara with a H25A motor.
problem is that it has a mis-fire on cylinder 4. ive swapped plug, coil, lead, injector to different cylinder, but the miss stays on cylinder 4. compression test and leak down test were spot on.
the only thing ive noticed is the plug is black, compared to other cylinders, but, still has a spark.
any help please????
cheers
weemsy
H25A V6 with a mis-fire
H25A V6 with a mis-fire
Its better to keep your mouth shut and appear stupid than to open it and remove all doubt.
Re: H25A V6 with a mis-fire
Weemsy wrote:got a Grand vitara with a H25A motor.
problem is that it has a mis-fire on cylinder 4. ive swapped plug, coil, lead, injector to different cylinder, but the miss stays on cylinder 4. compression test and leak down test were spot on.
the only thing ive noticed is the plug is black, compared to other cylinders, but, still has a spark.
any help please????
cheers
weemsy
test the voltage going to the spark plug. as it may be enough to jump the gap but not enough for it to burn all of the fuel ...
Your name is Bolo and it will stay that way until you have earnt the right to be called your real name........................ Bolo
Re: H25A V6 with a mis-fire
you also said you swapped the injector. have you seen the injector squirt fuel??? it could not be getting a pulse to work on number 4
Your name is Bolo and it will stay that way until you have earnt the right to be called your real name........................ Bolo
Re: H25A V6 with a mis-fire
gidday bolo,
yeah ive scoped the injectors and the coils, both have a matching pattern to other cylinders. (although that doesnt mean the firing point is correct).
just had the induction manifold off just incase the gasket was split (clutching at straws
)but all appears fine.
yeah ive scoped the injectors and the coils, both have a matching pattern to other cylinders. (although that doesnt mean the firing point is correct).
just had the induction manifold off just incase the gasket was split (clutching at straws

Its better to keep your mouth shut and appear stupid than to open it and remove all doubt.
Re: H25A V6 with a mis-fire

Your name is Bolo and it will stay that way until you have earnt the right to be called your real name........................ Bolo
Re: H25A V6 with a mis-fire
gidday bolo,
apparently they cant be swapped, as its a coded ecu for the immobiliser in the key
aint technology great!!!!
apparently they cant be swapped, as its a coded ecu for the immobiliser in the key



aint technology great!!!!

Its better to keep your mouth shut and appear stupid than to open it and remove all doubt.
Re: H25A V6 with a mis-fire
Weemsy wrote:gidday bolo,
apparently they cant be swapped, as its a coded ecu for the immobiliser in the key![]()
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aint technology great!!!!

Your name is Bolo and it will stay that way until you have earnt the right to be called your real name........................ Bolo
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Re: H25A V6 with a mis-fire
black spark plug means its running rich- probably so rich it wont fire nicely.
probably injector stuck open which would not show on scope as electrical pulse sent to injector would remain the same.
Guessing as im not a technician.......
probably injector stuck open which would not show on scope as electrical pulse sent to injector would remain the same.
Guessing as im not a technician.......
phone Ross Bolus (secretary of the BOP club) He'll save you.