Hey everybody I'm new here figured I'd reach out see if someone smarter then me could save me some time lol...... so I cant seem to get cylinder 1 to fire I have a 1990 z32 na with a 1991 na engine swap I believe its misfiring because the care idles rough and has a bit of hesitation when applying throttle... I pulled coilpack connecter to cylinder one and rpms do not change pull any other coilpack connector and the motor starts to stumble so I got new plugs and confirmed the cylinder is getting spark, did a compression test and cylinder 1 matches cylinder 3 and 4... so I thought probly a fuel issue... pulled all the fuel injector clips off and saw they were all full of green death.... replaced all the coil pack clips and injecter clips... still no combustion on cylinder 1 ok so then I focused in on the injectors had a hard time getting an ohm reading on injector 1 due to the corrosion on the pins figured better be safe then sorry and just pulled the plenum and replaced the injector on cylinder one. while the fuel rail was out I also replaced cylinder 4 injector due to its tip having a bit of damage on it.. replaced all the seals and slapped the plenum back on fired it up and still had a misfire and a fuel leak on injector 1 so pulled the plenum off again changed out cylinder 1 injector seal and once again reassembled.. leaky injector is fixed but still no combustion on cylinder one so I have spark I have compression and I have fuel anybody got any ideas where I should be looking, thx for the time

 

Have you tried swapping the coil pack itself with another cylinder? To rule out the coil pack. Also do the “injector stethoscope trick” if you stick a long flat screwdriver onto the metal injector cap, you should hear loud ticking each time the injector fires. I had an issue with the connectors, then the coil pack itself, and I have replaced 1 injector. Be careful removing the spark plugs, don’t beat on the threads or drop any debris into the cyl head. You could swap the spark plug with another cylinder to see if that one is shot. Don’t just jump and do a full injector swap or spark plug swap, because that is a lot of work and may not be the remedy.

 

Sorry I didn’t read all of the post. Try the coil pack swap! I have 4 spare coil packs I you need one cheap

 

I've done a coil pack swap and the misfire stays in cylinder one all coilpack are working correctly cylinder 1 injector is also working correctly cranking the motor with the spark plug out sprays a mist of fuel out the spark plug hole and if u run the engine with the motor fully assembled there is a clear rich fuel smell from the exhaust on bank 1 also when I pull the new spark plugs out cylinder one spark plug comes out clean and wet cylinder 3 and 5 come out black and all of bank two come out golden brown so could this misfire be due to a timing issue?

 

Maybe the cam position sensor could change the timing. I can’t help but think that if your timing was really off, then a whole side of your motor would be running rough. Could have stuck valves in that cylinder ? Any chance you have a bore scope and a way to crank the motor by hand?

 

Also if I remove cylinder one spark plug from the head but leave it hooked up to the coilpark and ground in out on the plenum while cranking the engine the spark plug is sparking......

 

If a valve was stuck would I still get a good compression test? Cylinder 1,3 and 4 all tested 165 - 170 thx for your time btw!

 

To my knowledge your compression test really validates the condition of your pistons and rings. When I did my compression testing, following all of the write ups, I did not rotate the motor to change the position of the valves. So i don’t think that matters. On other applications the stuck valve could throw compression off, but the valve may seal air, but be stuck so combustion doesn’t occur.