purplecatty
Active Member
- Joined
- Feb 11, 2007
- Messages
- 3,792
- Reaction score
- 6
COPS are simple and easy to replace. But sometime they are hard to diagnose or replace on some vehicles.
Suppose if you come over Catty's place to diagnose his car. You pulled a code P0304, cylinder#4 misfire detected from your pocket scan tool.
What to do? Check all fluid levels and visual inspection on the engine to see if anything broken or missing, before you investigate the misfire condition. Start the engine and run. Grab a long driverscrew and probe #4 injector as you feel pulses from injector, move a driverscrew to another injector to see if there is same pulse. Next....(Turn engine off)
Remove #4 COP ( make sure you examine it for carbon tracks or cracks) from the cyl #4 and swap #4 COP to cylinder #1 (as you random any COP if you like to swap)
Remove #4 spark plug from cyl #4, swap to cyl #3 ( don't swap to cyl#1)
#3 spark plug swap to cyl #4
Install #1 COP in cyl#4. Write down record of swapping COPS and plugs
Clear code. Take a car for drive around and observe the MIL. MIL pop up again. You are exciting to pull the code(s).....
P0301, cylinder#1 misfire detected that indicates bad #4 COP cuz you swapped. Sound easy diagnose.
P0303, cylinder #3 misfire detected that indicates bad #4 spark plug cuz you swapped #4 plug to cyl#3. Understand clear?
P0304 cylinder #4 misfire detected, same code after swapped COPs and plugs. You would suspect low compression or bad #4 injector?
You can try to swap an injector to another position to see if code changes
The Number One cylinder is on left bank side along with 3,5,and 7. On right
bank side is 2,4,6, and 8.
Beware of the disabled injector cuz some modern OBD-II PCM will disable injector(s) when detects misfire cylinders.
Highlander, what do you think? Even Catty dont have a fancy scopemeter, he can do the method of diagnositic. deafsmogtech
Yes, I can feel injector pulses with my fingers. I will do what you suggest. The only problem is that I don't have OBDII scanner yet. Originally above my posting, I will take my truck to auto part and borrow their OBDII to find out what's engine check light telling me. Then after replacing parts, see how engine runs. If it runs the same after check light been reset, I will do further investigation regarding to COP and Injectors and do tricks on that. If one of injector is bad, I know it's over $100 to replace it. Injectors are unpredictable that it may go bad too soon or go bad after 200k miles. Also will check the voltage spike on each injector to see how strong pulse voltage.
Even Catty dont have a fancy scopemeter, he can do the method of diagnositic. Yeah, that's correct!! I don't have that fancy stuff. I will use the methods you suggested.
Another thought, Fuel filter?? I haven't changed it since I bought my truck. It's now 73,000 miles on it. I am fully aware that fuel filter must be changed between 50k to 100k miles. I'll have it replaced.
I haven't done anything on my truck yet. I was soo busy last week catching things up in my house and other things cuz I was on one week vacation. I had alot things in my mind tho.
Catty