1977 280z misfires.. valve clearences?
09-16-2014, 02:09 PM
#1
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Join Date: Apr 2014
Posts: 8
1977 280z misfires.. valve clearences?
Alrighty, well I was getting no where with my car's problems before. It used to never start, and when it did it only ran on the front 3 cylinders and couldn't rev for nothing
Turns out it was the injectors... I replaced them and it ran like brand new! I had also installed a megasquirt system to replace the old EFI system (Works great). Now I have a problem. Cylinders 3 and 4 are not firing. I know this because when I remove the injector connectors when the car is idling nothing changes to the idle. When I remove the spark plugs theyre wet and smell like fuel. I can feel the injectors firing by feeling the clicks, so I thought it was ignition. I've already replaced the cap, rotor, plugs, plug wires, and been through all the tests to find that the ignition circuit is fine. Nothing wrong with it. Anyway, can it be the valve clearances? is there anything I'm missing? I'm sorry if this posts seems a bit jumbled. If anyone has any questions feel free to ask! Thanks!
Turns out it was the injectors... I replaced them and it ran like brand new! I had also installed a megasquirt system to replace the old EFI system (Works great). Now I have a problem. Cylinders 3 and 4 are not firing. I know this because when I remove the injector connectors when the car is idling nothing changes to the idle. When I remove the spark plugs theyre wet and smell like fuel. I can feel the injectors firing by feeling the clicks, so I thought it was ignition. I've already replaced the cap, rotor, plugs, plug wires, and been through all the tests to find that the ignition circuit is fine. Nothing wrong with it. Anyway, can it be the valve clearances? is there anything I'm missing? I'm sorry if this posts seems a bit jumbled. If anyone has any questions feel free to ask! Thanks!
09-17-2014, 04:21 AM
#2
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Join Date: Feb 2011
Posts: 302
Actually, unless you're leaving out details, you don't know that cylinders 3 & 4 aren't firing.
Have you used a tool like (see picture below) to see if you have a spark on those cylinders?
Have you verified the injectors on those two cylinders are closing and not flooding the cylinder? You mentioned the plug are wet.
Have you done a compression check on the cylinders in question? (This isn't really related to the cylinders not firing, but it does relate to your question on valve clearance.)
Have you used a tool like (see picture below) to see if you have a spark on those cylinders?
Have you verified the injectors on those two cylinders are closing and not flooding the cylinder? You mentioned the plug are wet.
Have you done a compression check on the cylinders in question? (This isn't really related to the cylinders not firing, but it does relate to your question on valve clearance.)
09-17-2014, 10:59 AM
#3
Registered User
Thread Starter
Join Date: Apr 2014
Posts: 8
Actually, unless you're leaving out details, you don't know that cylinders 3 & 4 aren't firing.
Have you used a tool like this (see picture below) to see if you have a spark on those cylinders?
Have you verified the injectors on those two cylinders are closing and not flooding the cylinder? You mentioned the plug are wet.
Have you done a compression check on the cylinders in question? (This isn't really related to the cylinders not firing, but it does relate to your question on valve clearance.)
Have you used a tool like this (see picture below) to see if you have a spark on those cylinders?
Have you verified the injectors on those two cylinders are closing and not flooding the cylinder? You mentioned the plug are wet.
Have you done a compression check on the cylinders in question? (This isn't really related to the cylinders not firing, but it does relate to your question on valve clearance.)
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