miss firing on one bank?? help

[potshots007]

hey everyone, my car been miss firing for a while, well since i got it about a year ago, i have checked compression, and is all good, i have replace DFI module, coil pack, plugs, leads, crank sensor, and it still got me bugger, now i put the timing light on each lead cos it should spark all the time or every second reviloution, and i check all the right side, 4,2,6 and they are sparking beautifully, not missing a beat under all revs, then i checked the other side (left) 1,5,3 and they are all intermittent, and when you open up the throttle it almost stops sparking, even on idle, it sparks then it doesnt, sometimes constant and so on, got me absolutley bugger, just wondering if anyone had any ideas or anything i could check or test,
i have also tried another module, another coil pack, tried new leads again

cheers, nick

[88GreenVN]

When you tried the different module/core pack - it still miss fired on 1,5,3?
MAP, Throttle & oxy sensors would not affect spark. - Good problem to solve.
Does the car have any fault codes from the computer?

[aussieghostrider]

this is gonna sound silly but maybe loose injector or injector lead on that side or maybe wiring is burnt out and when car heats up gets worse ??

You have replaced most of everything ... hmmm

does you car use coolant .. maybe inlet manifolds leaking into those cylinders...

maybe electric regulator is dead... my car was doing same sort of thing ... loss of power idling rough like it was gonna stall... thought was alternator but was regulator,sounds like wiring is loose or burnt out on that side...

Try taking of battery lead for 5 mins to reset computer......

maybe loose earth or similar ???

Another thing to look for is if you have a leaking radiator hose or similar that can cause havoc with your electrical systems....

thats all i can think of....

let us know how u go mate..

[potshots007]

yeah, its got me a bit buggered, it does it all the time, but ive got it narrowed to somewhere before the coilpack or module, when i get enough time im going to trace every wire and make sure nothing is loose or broken or melted etc. also it definately a spark issue only on the 135 side of the coilpack, also yeah it is throwing a rich exhaust code, if i remember its code 45, and i have reset the commputer many times, what does the DFI mofule take signals from? cas, what else or does it just go back to the ECU?
thanks everyone for helping me,

also, can i turn the coil pack around? swap the wires around?

[88GreenVN]

The core pack fires both sides at the same time I think. To help burn fuel on the waste cycle. So it's not the core pak. code 45 rich - eg not good spark = unburnt fuel.

[potshots007]

what im saying is it fires constantly on the 426 side of the core pack, and on the 153 side of the pack it is not constant, fires every now and then, but yeah i think if i sort out the miss firing issue i will fix me code,
cheers, nick

[88GreenVN]

Ok if its running rich.. getting fuel. the code is no real help but to say its getting fuel. So the injectors are not the issue. If a 2nd core pac does the same thing. Can't be that. Dont know what else delivers spark to the engine other than the leads (all 3 leads doing the same thing is unlikely) and the injector wires.

Could be the injector electrics. Sorry I'm out of help.

[commy92]

plugs?????????

[potshots007]

plugs new, leads new, coil pack new, dif module new, cas new, also bought secondhand coil pack, dfi module, cas and all do the same thing,
where does the dfi module take signals from?
got me bugger, but will have a real hard look on the weekend,
thanks for everyones help

[88GreenVN]

Let us know just in case it happens to us....

[potshots007]

yeah, no doubt i will, but i seriously hope it never happens to anyone else, might get a secondhand ecu and see if it makes any difference

[88GreenVN]

Have you opened the DFI unit? to have a look at the guts of the thing.

[potshots007]

yeah, looks alright, then secondhand one lookd good two, got me puzzled why its only missing on one side of the poil pack,
also i have tried the coil pack and dfi module on another Vn and runs perfect, doesnt miss a beat at all, got me buggered, but yeah im just going to go through all the wiring and check it all, might even try another loowm whcih i have out the back, see if it helps, also change the ecu , i will get to the bottom of this as soon as i can

[potshots007]

well i got a new loom, and still no different, still not sparking constant on one side of the coil pack, i also tried another ecu and still no different, this is a very confusing problem and has me very well buggered now, anyone can suggest anything else?

[vt1538]

On a wasted spark system one bank fires with the positive side of the coil, the other fires with the negative side. The reverse side takes more energy to fire so this may be why you have a scattered beam on one side of the coil.
Another thing to watch for is that a bad spark plug or lead on one bank can cause the other bank to miss.
Also if you are using a timing light that clips on the lead some of these clips need to face in the direction of current. If this is so with your timing light you could be connecting onto one bank with the incorrect current flow.

[potshots007]

yes i am using an inductive pick up timing light, and it is fitted correctly, might get another set of leads and plugs again and see if it makes any difference

[vt1538]

What I meant to say mate is if your inductive pick up is directional, one side of the coil current is reverse & may need the pick up to be reversed on the lead to function correctly.

[potshots007]

ok, now i understand, will try that tonight. dont know what else to try, might buy another car, some jap car or something cheap to run. but i will keep working on this problem until i figure it out,

[vt1538]

Might be worth checking all the earth leads for good clean contact as well. There is a few of them so follow the loom closely.
When you drive the car when is the miss most obvious. Does it only happen when you accelerate or the car is under load?
With the car running rich it could be an injector problem.

[immortality]

Have you looked at the crank angle sensor under the balancer, i've checked the gregories manual the only inputs to the DFI module are the ecu and the crank sensor plus outputs to the tacho so i would suggest that you possibly have a bad connection/wire between the DFI module and either the ecu or Crank angle sensor. i don't think it's related to the injector cause this engine runs a group injection system where all the injectors open/close together on a single circuit with twin outputs from the ecu. good idea though to use the inductive timing light to check the firingoutput of the coils etc

[vt1538]

If the CAS has a wiring problem the engine will not start as it will not trigger either the fuel or spark. Since the same signal that triggers the left bank also triggers the right a fault in this would show up on both sides of the engine also.
I would put the miss down to a seperate issue like a stuck or leaking injector or something along those lines.

[potshots007]

i dotn know now, ive givin up,

[adam69]

Hi,dont know if this helps coz i have a V8 but i had a miss, put new plugs,checked leads checked comp,all OK.turned out i have a stuffed cam that was giving number 5 piston some trouble.

[immortality]

it could be the CAS as it's actually2 sensors in one, make sure its set correctly, rotate the engine by hand and see if any of the fingers on the back of the balancer are bent etc as this can cause problems. mine was touching the fingers on the balancer and it wore it out. at first it seemed to run a little rough, one day the missus was driving it and it was sputtering/backfiring everytime she touched the gas pedal, drove it homethough at about idle which was bad as well , luckly she was only one street from home ( she doesn't like walking). changed the sensor etc and all was fine. might pay just to change the balancer also, most engine reconditioners say that everyone they have seen seemed buggered in some fashion or another. other than that i still think it's a wiring/ bad connection issue, if it was a stuck injector or bad cam it would most likely only be missing on that cylinder, not the whole bank but take the tappet cover of the bank thats missing run the engine and see if everythings moving nicely there. you can also just put a dail gauge on the end of each rocker and turn the motor over by hand and compare all the intake valves and all the exhaust valves lifts etc. can you get hold of the gregories manual you will need it to check the outputs on the ecu etc to trace the wiring, can be done without a wiring diagram but will take 10x longer

[vt1538]

At no stage has it been shown that the whole bank is actually missing. While he is getting a intermittent spark showing on his timing light it is more than likely caused by this bank having reverse current flow not an electrical issue.
With the reverse side needing greater current to fire the plug a faulty coil is usually the reason for a miss to occur on this side. These have already been replaced & tested on another vehicle.
I would be removing one injector plug at a time & try & isolate the miss to a single cylinder & go from there.