Misfire on cylinder# 5 (Code: P0305)
Ford Ranger, 3.0
Misfire on cylinder# 5 - changed plug on # 5 Still misfiring on # 5 - noticed a squirrel had been chewing some of the plug wires - replaced plug wires Still misfiring on # 5 Suggestions for diagnosis? I know it has to be either a fuel-air mix, compression, or fire issue. I just don't know the most reasonable step from her. |
It is limited to one cylinder. Test the fuel injector. Use a stethoscope or a length of garden hose and listen to the injectors. If #5 is making no noise check the electrical circuit.
The coilpack may be shot. If you have 100K + that would be my first guess. What year and mileage on your Ranger? |
2000
154,000 THANKS! I'll try your idea once I figure it out completely. Can a coilpack be bench-tested. |
Tested the injectors. #5 is clicking just like 1, 2, 3, 4. Can't reach #6 with the stethoscope, but no mis-fire is indicated on 6, so ignoring for now.
Of course I guess clicking doesn't mean they're clean ... I guess it's on to the coil pack, |
carpheadhttps://www.fordforum.com/forum/imag...ser_online.gif
Junior Member Join Date: Feb 2009 Posts: 5 https://www.fordforum.com/forum/images/icons/icon1.gif 2000 154,000 "THANKS! I'll try your idea once I figure it out completely. Can a coilpack be bench-tested." ? Yes, check U-tubes for a pictorial on how to test COP's. The problem is getting down to the COP. skip. |
Using a spark tester, I'm getting sparks from all 6.
While I've got time on my hands, I think I'm going to grap a compression tester. |
Compression was fine - all between 165 and 172.
... but I think I found the problem when I pulled the plugs to test comp. All plugs showed signs of heat, high speed glazing, and worn to a nub electrodes. The one in #5 that had been replaced 60 days ago had actually been replaced with a 32 (edit: I mean replaced with a 22) which is for the 4.0 - a miss on my part. I'm going to try using a slightly cooler plug, if I can figure out which one. Thanks for all your help. Should know within 50 miles if it's a fix. |
Nice going Carphead!
Let us know how it goes. Get OEM plugs or some plugs that are very similar. Stay away from fancy stuff. To skip1930; This is just a clarification: Carphead's engine does not have COPs (Coil on Plugs). It has a coil pack and wires from the coil pack to the plugs. Coil packs can develop internal shorts. Also there can be shorts at the towers where the wires attach. A coil pack: https://encrypted-tbn0.gstatic.com/i...6fa88hAs79qNFA COPs:https://encrypted-tbn3.gstatic.com/i...gPB5nGCwWqGyyQ |
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