Home
About
Sign Up Now
Log In
Q&A Categories
Find a Question:
misfire 03 ranger-3.0
Jan
24
2011
ther is a misfire on #6. ther is good fire,fuel & compreshon
Answer #2
I am a Lincoln/Mercury trained drivability technician and will try to assist you with this problem but I need a little information from you first.
Is the miss constant or intermittent? If intermittent, when does it occur ie.. under load on hills, sitting at a stop light, only at idle?
I assume, from what you are saying, there is good spark from the coil to the plug (using a spark tester), fuel pressure is correct (what numbers [KOEO and KOER*] did you get and does it bleed down) and compression is very comparable (how much compression) to other cylinders on the same engine. Do you have a lab scope you can check the secondary ignition patterns with? Have you been able to check the injector patterns (voltage command and current)? Have you connected a vacuum gauge to this engine? How much vacuum do you have and is the needle steady or erratic? If erratic, does it swing with a wide sweep or just a small \”wiggle\”?
Have you ruled out the possibility of a vacuum leak with a smoke test? Have you scanned it, other than checking for codes, to see what the fuel trims are both long and short term on each bank? These things can all point you in a direction to assist you in fixing this truck.
*KOEO = Key On Engine Off
*KOER = Key On Engine Running
If you can get me this information I will attempt to explain what may be going on and what to do next.
Thank you,
Diagtech055
PS..I know this is alot to ask but since I am not there with you, I am asking for this information to decide what to suggest next.
Answer #3
Make sure your coil cylinder can jump a gap with a spark tester. You may have fire but weak fire and need a coil.
Answer #4
Assuming you have good spark and proper injector pulses, it could be a broken valve spring.
Answer this Question
You must be Logged In to post an Answer.
Not a member yet? Sign Up Now »
Star Points Scale
Earn points for Asking and Answering Questions!
[1 - 25 
]
[26 - 50 
]
[51 - 500 
]
[501 - 5000 
]
[5001 - 25000 
]
[25001+ 
]
Sponsors
Answer #1
I am a Lincoln/Mercury trained drivability technician and will try to assist you with this problem but I need a little information from you first.
Is the miss constant or intermittent? If intermittent, when does it occur ie.. under load on hills, sitting at a stop light, only at idle?
I assume, from what you are saying, there is good spark from the coil to the plug (using a spark tester), fuel pressure is correct (what numbers [KOEO and KOER*] did you get and does it bleed down) and compression is very comparable (how much compression) to other cylinders on the same engine. Do you have a lab scope you can check the secondary ignition patterns with? Have you been able to check the injector patterns (voltage command and current)? Have you connected a vacuum gauge to this engine? How much vacuum do you have and is the needle steady or erratic? If erratic, does it swing with a wide sweep or just a small “wiggle”?
Have you ruled out the possibility of a vacuum leak with a smoke test? Have you scanned it, other than checking for codes, to see what the fuel trims are both long and short term on each bank? These things can all point you in a direction to assist you in fixing this truck.
*KOEO = Key On Engine Off
*KOER = Key On Engine Running
If you can get me this information I will attempt to explain what may be going on and what to do next.
Thank you,
Diagtech055