misfire???

[owen180]

got the 180 up and runnin again but have a misfire in cylinder no 4. Each time i unplug the coil pack in 1,2, and 3 the engine dies but in 4 it makes no difference. Change over coils and plugs and no luck. Even changed amp pack. Checked continuity of cables and they seem fine. Any idea's lads cause this is buggin me. Also anyone no wat voltage should be at the coil packs

[nissan_doctor]

Have you done a compression check on that cylinder and checked the rocker arms?

[owen180]

did a compression test. 110 psi across the board. Haven't checked the rocker arms? Enlighten me please cause i'm no mechanic

[nissan_doctor]

did a compression test. 110 psi across the board. Haven't checked the rocker arms? Enlighten me please cause i'm no mechanic

The rocker arm opens the valves when its compressed by the cam lobe. They are known to break on SR engines and if its has broken then the valves won't open, which would give you full compression but no air/fuel mix or exhaust outlet, causing a misfire. Remove the rocker cover and you will see the rocker arms between the cams and valves.

[colm]

did a compression test. 110 psi across the board. Haven't checked the rocker arms? Enlighten me please cause i'm no mechanic

was that a hot or cold compression test? seems fairly low for an sr

[Taffy]

had the same prob wid mine was the exhust rocker on number 2 was a easy enuff fix

[180sxbreaker]

was that a hot or cold compression test? seems fairly low for an sr

i wit u on that note colm it is low...

and wat happened taffy happened me twas number 2 wit me aswell

[owen180]

that was a cold test. Wat should it be. Got it sorted today. Timing was out. Now runnin again. Dyno'd too. So ready to roll for next week