Cly #3 Not Firing

[White GTS-T]

Hoping for some help on this one.

RB20DET

Mods:

Apexi Power FC

Apexi AVCR

HKS 2530 Kai

Z32 AFM

3" turbo back exhaust

Greddy fmic

Bosch 040

Nismo 555cc injectors

Tomei Poncams

Splitfire coils

Brand new bcpr6es-11 plugs

This problem started after i installed the following mods, prior to this the car ran fine.

I recently installed Nismo 555cc injectors, Tomei poncams and a 2530 turbo. All parts were brand new. New timing belt, fuel filter, all new gaskets etc were installed at the same time.

Compression:

Compression test results: Dry test

Cyl #1: 145psi

Cly #2: 145psi

Cly #3: 135psi*

Cly #4: 145psi

Cly #5: 145psi

Cly #6: 145psi

Compression test results: Wet test

Cyl #1: 150psi

Cly #2: 150psi

Cly #3: 150psi*

Cly #4: 150psi

Cly #5: 150psi

Cly #6: 150psi

* I put the 15psi gain down to the fact that the cylinder bore is awash with fuel.

Cylinder leakage test results:

Cyl #1: 6%

Cly #2: 6%

Cly #3: 4%

Cly #4: 6%

Cly #5: 8%

Cly #6: 12%

Spark:

I have battery voltage at the coil harness, and can see the computer switching the earth with a noid light and LED test light. I can lift the coil pack up while its running and here a very auidable crack, crack, crack. I can earth out the spark plug on the rocker cover and see the spark jump > an inch to the rocker cover. I have changed out the CAS, coilpacks, ignitor, coil harness, (with known working items) computer, (with stock item) and countless new spark plugs. With a timing light on the balancer it reads the same as the ignition timing read out on the power fc hand controller.

Fuel

I have scaled the new injectors size and latency in the power fc and rechecked my calculations numerous times. I have injector pulse and can see the computer switching the earth with a noid light and LED test light. I have the scaled voltage at the injector plug and can hear the injectors tick, tick, tick with a stethoscope. I have swapped out the injector from Cyl #2 which was running fine, with Cyl#3 which is missing, with the same result.

Cams/Lifters

After running the cams in i pulled the rocker covers off and the wear on the new lobes is perfect. Opposing cylinders are rocking with the other on compression. I can turn the lifters with the lobes pointed towards the rockers covers, so they are free. The lifters are not noisey and i have taken the car for several drives and got it hot.

Other

There are no vacuum leaks. I can pull a vacuum line of and spray accelerant in the plenum and cyl # 3 doesn't pick up. I have had a boreoscope down the cylinder bore and it looks fine and even down the No#3 intake runner to make sure there are no foreign objects in there blocking airflow.

To Do

About the only thing left to do that i can think of is to pull the fuel rail off with the injectors still in and turn the CAS over by hand and ensure that the spray patterns are ok and that the injector is infact firing. Try some non resistor type plugs, as they make the coilpacks work harder.

As you can see i'm starting to go around in circles, so any help/suggestions/ideas are welcome as it may be something very simple that i have overlooked.

Thanks,

Tim.

Edited April 21, 2010 by White GTS-T

[mad082]

so i am assuming that you diagnosed that it was cylinder 3 not firing by unplugging something to do with cylinder 3 while the car was running to not have it make any difference?

the issue you are having could still be spark related. it could be that the coil is arcing out when it's in the spark plug valley, when then you are simply testing to see if it will fire in open air it will work. i would try swapping a spark plug and coil from a different cylinder and see what happens.

also have you checked that the injector is getting power?

[White GTS-T]

Yeah, if i remove the ignition coil harness from cylinder #3 there is no change in engine speed. If i pull the spark plug out it is just wet with fuel. I have tried swapping the coil packs around but it makes no difference. I have also tried about 10 new plugs to no avail. I have 13.8V at the injector plug and i can see the computer switching the earth to the injector with a noid light and can hear the needle lifting off the of the injector with a stethoscope.

[badhairdave]

Interesting problem. So it doesn't fire at all?

If you take it for a drive and open it up can you blow the plug clean and it starts to fire? Or alternately if you bring the piston to TDC and blow it dry with a compressor, then install a new plug and start it immediately will it fire?

[White GTS-T]

Nope, it doesn't matter if i just clean the plug or fit a new one it still won't fire, even after the first hit of the key, cylinder 3 hasn't run since putting the car back together and every time i blow the cylinder out it just smells of fuel. Today i fitted a new ignition harness and new bcp6es-11 non resistor type plugs, but to no avail. I've ordered a hks twin spark, but i doubt it's going to do anything. When i was earthing out the plug on the rocker cover the spark was more of an orange coulour than i was expecting, i thought would be a brighter blue/white. However, i'm starting to think that the problem has to be mechanical, as i figure i've coved just about everything electrical. I think i'll pull the lifters out. Does anyone have a rough idea how much new ones are?

[drf76]

When i was earthing out the plug on the rocker cover the spark was more of an orange coulour than i was expecting, i thought would be a brighter blue/white.

any luck???,

how did the spark look on the other plugs, orange aswell. seems you have covered everything i would have done..very interesting problem. stumped lol

long shot but are the cam lobes opening at the right time on cylinder 3, i know how that sounds lol but it just seems you have covered everything simple and i have heard cams being ground incorrectly before on a factory car haha ford transit!

[White GTS-T]

Not as yet. The spark on the other cylinders was the same. I haven't got around to pulling the lifters out yet as i have been at trade school all week. But i will be doing it this weekend. I was thinking that maybe one or more of the lifters in cylinder #3, while they are pumped up, as they are not noisy, is not bleeding down and has too much oil pressure and is acting like a solid lifter giving zero valve lash? Maybe the problem has been there all along but the higher lift on the after market cams has exacerbated the problem? I'm not too sure, but I know what your saying about the cams. I've spoken to a few people now who have said they have seen new cams ground incorrectly, but you would think if that was the case that the opposing cylinder to #3 (Cyl#4) would be missfiring aswell? Also when i did the leak down test in firing order, (1-5-3-6-2-4) as cylinder #3 came up to TDC it had very little cylinder leakage, proving the valves are closing at the right time.

[BH_SLO32]

I have had an intermittent problem with one of my cylinders firing and it is a problem in the actual coil pack wiring harness associated with the specific cylinder (#3 or 4 from memory). May pay to have a good look at the coil pack plug connection and if possible borrow someone elses coil pack loom to eliminate it from the equation.

[White GTS-T]

I had swapped out the ignition loom/coil pack harness with a know working item but it now has a brand new nissan one fitted.