Hi all,

Have a saff cosworth 4x4 in the workshop today that has left me totally stumped. car has a missfire (running on 3 cylinders) at all RPM including idle. pulling an ignition lead to find the cylinder with the problem doesnt help, engine dies when each one is removed.

If you remove injector plugs 1 or 4 then it will die, pull 2 or 3 and it will keep running with very little change to engine note.

swapped injectors round, still no change, car will still run fine (except on 3 cylinders) with injector 2 or 3 unplugged but not 1 or 4.

all injectors are pulsing properly with correct voltage

all cylinders have good compression. so changed plugs, leads, coil, points, crank sensor, map sensor and its still the same.



any ideas

 

Have you tried a water temp sensor mate. Its on the passenger side of the engine right at the back below a coolent pipe. What are the 4 teeth look like on the bottom pulley?

 

am I right in saying the order of the ignition leads are as follows:


2 C 1
4 3



when looking at the distributor with the terminals pointing towards you?

 

mine turned out to be a nackered valve

 

ignition leads were on in the wrong order. so sorted them out and missfire is still there. can pull leads 2 and 3 off the plugs with no change to engine note. leads are working fine, so are the plugs when tested out of the engine but once they are refitted they dont seem to be firing correctly.

any reason why cyl 2 and 3 would be causing this problem?

 

head gasket leaking inbetween the 2? - is your dizzy cap ok, no furr around the posts inside and no ground down bits where the rotor arm has been catching ?

 

that was the first thing I tested, no leakage between 2 and 3.

looking at the phase sensor, how is this removed from the distributor? removed the 3 screws but the plate wont come over the two teeth on the shaft?

 

Answered on other thread.
If you remove a lead and it even ALTERS, then that cylinder IS firing, as if it were DUD it would still be dud.
I would firstly change the plugs, as one may have a high resistance, or a lead.
The phase sensor will NOT cause a particular misfire like this, unless alignment was out, it then would pick on the weakest cylinder, check for a play in the shaft as these are not unknown to pick up the bush and spin in the housing.
I would also do the usual look for air leaks, as this will affect the waekest cylinder firtst.
tabetha

 

I HAVE THE SAME PROBLEM JUST NOW!!!!
been at it for weeks i could take both 2 an 3 plug lead of and makes no difference!!!

now it wont start at all just spluttes once in a while
the plug on my temp sensir has been changed at one time?? would it matter if the wire's were the wrong way round??
i also dont have an earth strap on my emgine goint o fit one today that might be an issue on yours matey??? but again could be the cap etc etc etc

 

I would do a compression test to make sure the valves arnt damaged. Then i would check the injectors to make sure they are working. Do you know if number 2 and 3 plug leads are sparking.