Nissan 300z misfire


#1

My fiance is having trouble diagnosing a misfire on the second cylinder of his 300z. He has ruled out electrical. Any ideas for us?


#2

Sticky injector?


#3

more info would be good.

that question is WIDE open.

what has he done?


#4

nope but thx


#5

He says he has done everything and it all leads him back to square one. He is very frustrated right now so I cant get a real answer other than he even followed up in the FSM, you know, the book that Nissan Tech’s refer to? And it’s not even helping him.


#6

Does a “reading” of the spark plugs show any abnormalities on that cylinder?


#7

A definition of “ruled out electrical” and “has done everything” would help.
How has this been determined, what if anything has been replaced, what codes are being shown, how many miles on the car and what year, etc.?

If the car has half a million miles and finally dropped a cylinder due to low compression then one can throw parts at it all day long without solving anything.


#8

Its flooded with fuel, plug itself is drenched


#9

Power Balance Test

Swapped coil packs

swapped plugs

Check continuities of coil packs

Check ohm reading on injectors

ohm read PTU

ohm read CAS

did continuity test between PTU terminals / ECU terminals / Coil harness

swapped PTU’s

ran ecu codes, no codes

did a pulse signal test on dead cyl #2

Its a 1991 with over 95000 miles


#10

Power Balance Test

Swapped coil packs

swapped plugs

Check continuities of coil packs

Check ohm reading on injectors

ohm read PTU

ohm read CAS

did continuity test between PTU terminals / ECU terminals / Coil harness

swapped PTU’s

ran ecu codes, no codes

did a pulse signal test on dead cyl #2

Its a 1991 with over 95000 miles


#11

You checked to see that the signal to the injector was good, but did you try swapping the injector itself? My gut suggests that the inject may be leaking. A single saturated plug where all the ignition items have been checked is a real strong symptom of same.


#12

compression check?

cylender leakdown test?

back to basics,(seems that way)

good luck.