i have 2l blacktop zetec, i'm trying to tune it on megasquirt. but when you look down the inlet on cylinder 2 when the engine is running you can
see it light up, i've tried adjusting the spark table up and down but with no effect other than make the engine run rougher than it is.
any help much appreciated
incorrect cam timing or you have the HT leads mixed up?
i've checked the timing and it's right to megasquirt. ah with the leads i think i have. is there a diagram showing the correct way?
just checked and the leads are on correct.
no, incorrect cam timing not spark timing. Is there any possibility the cambelt has slipped or that the cams could have been fitted incorrectly?
Also the inlet valve could be sticking open, has any work been carried out on the engine?
Weak mixture will cause this, partially blocked injector perhaps?
Not timing surely..otherwise ALL ciylinders would exhibit the same symptoms no?
My prognosis given the symptoms is either a duff injector or manky spark plug...swap them around and c the outcome.
quote:
Originally posted by Fatgadget
Not timing surely..otherwise ALL ciylinders would exhibit the same symptoms no?
My prognosis given the symptoms is either a duff injector or manky spark plug...swap them around and c the outcome.
quote:
Originally posted by cd.thomson
no, incorrect cam timing not spark timing. Is there any possibility the cambelt has slipped or that the cams could have been fitted incorrectly?
Also the inlet valve could be sticking open, has any work been carried out on the engine?
i just swapped the injector over with another cylinder but it's still doing the same thing
Do a compression test
i'll have to go get a tester for that. but assuming that test comes back ok. what's next.
if the test comes back and the pressure is low, is that piston rings?
Is this the first time of running the engine since wiring it for Megasquirt?
If so you may have the wiring for cylinders 1&3, then 2&4 incorrect in relation to the coil pack connections.
Is this the first time of running the engine since wiring it for Megasquirt?
If so you may have the wiring for the injectors to cylinders 1&3, then 2&4 incorrect in relation to the coil pack connections.
no this isn't he first time the car has been run, i've just upgraded the inlet side from a diy manifold to a st170 one, although i'm starting from scratch on the tuning
also i'm using simultaneous firing so that shouldn't matter
just a small update been messing with the car more, the throttlebodies aren't balanced and adjusting them is helping although the balancer i got is crap so need to get another one
Sounds to me like either a sticking inlet valve, or the tappet have been wrongly adjusted holding the valve open just a tad. Does the Black top have hydraulic lifters, if so then that one in over pumping. My opinion, for what it's worth! Cheers Ray
It has solid lifters, how would you fix a sticking valve?
quote:
Originally posted by Chippy
Sounds to me like either a sticking inlet valve, or the tappet have been wrongly adjusted holding the valve open just a tad. Does the Black top have hydraulic lifters, if so then that one in over pumping. My opinion, for what it's worth! Cheers Ray
quote:
Originally posted by MakeEverything
quote:
Originally posted by Chippy
Sounds to me like either a sticking inlet valve, or the tappet have been wrongly adjusted holding the valve open just a tad. Does the Black top have hydraulic lifters, if so then that one in over pumping. My opinion, for what it's worth! Cheers Ray
^^ What he said ^^
If you can "See" into the cylinder, then the valve is open! It should be closed. Either that or you have a seriously hot inlet valve, and some worrying detonation going on.
quote:
Originally posted by MakeEverything
quote:
Originally posted by Chippy
Sounds to me like either a sticking inlet valve, or the tappet have been wrongly adjusted holding the valve open just a tad. Does the Black top have hydraulic lifters, if so then that one in over pumping. My opinion, for what it's worth! Cheers Ray
^^ What he said ^^
If you can "See" into the cylinder, then the valve is open! It should be closed. Either that or you have a seriously hot inlet valve, and some worrying detonation going on.
Dont dismiss it though.
The carbs will have a vacuum to lift the gizmo inside. ideally, i think id be taking the head off to have a proper look, but i know that takes time,
effort and money!
No need to take the head off to check for burnt/sticking valves! Do a cylinder leakage test and check/adjust the valve clearances
well if it still acts odd after i've played with the balancing and fuel/spark. i'm gonna start looking at removing the head or checking for
a sticky valve, really not keen on that just yet. but thanks for the suggestions, this weekend will soon tell what i need to do..
Fingers crossed
Imbalanced throttle bodies will easily cause this since the fueling can't be correct for every throttle body if they are opened different
amounts. The one you are getting flames back through is probably running very weak.
Can't be incorrect cam timing on a single cylinder unless the camshaft has somehow been twisted!