cooldrums Posted February 5, 2012 Share Posted February 5, 2012 Hello all, I am a newbie to the forum so be forewarned. I am in the process of solving a misfire problem due to water in the chamber (lack of a better term) of the spark plug bank area. Had an engine light come on and a cylinder 3 misfire code. Cleaned out all water, replaced all plus with double platinum NKG plugs and also replaced coil 3. Still have the issue. So i noticed there's some sort of sensor located between plugs 2 & 3 on the top. Can anyone point me in the right direction as to what this is? It was holding water as well, not sure if it got down inside it or not. Thanks!! I have gone through my Haynes manual and scoured the net to no avail. 0 Quote Link to comment Share on other sites More sharing options...
FusionDiffusion Posted February 5, 2012 Share Posted February 5, 2012 (edited) I believe it's the cylinder head temperature (CHT) sensor. Pop the boot off and look down in the hole to see if there's any water. The following site talks about replacement, and includes a table at the bottom so you can test the sensor's resistance to see if it's functioning properly. http://www.autozone.com/autozone/repairguides/Zephyr-2006-Fusion-Milan-2006-2007-MKZ-2007/Components-Systems/Cylinder-Head-Temperature-Sensor/_/P-0996b43f8075c823 If you're sure the spark plug is okay, the next thing to suspect would be the fuel injector on that cylinder. Are you getting any other codes besides P0303? If you believe water got into the cylinder and you hydrolocked the engine, you should do a compression test. You may have physically damaged the engine. Edited February 5, 2012 by FusionDiffusion 0 Quote Link to comment Share on other sites More sharing options...
cooldrums Posted February 5, 2012 Author Share Posted February 5, 2012 I believe it's the cylinder head temperature (CHT) sensor. Pop the boot off and look down in the hole to see if there's any water. The following site talks about replacement, and includes a table at the bottom so you can test the sensor's resistance to see if it's functioning properly. http://www.autozone.com/autozone/repairguides/Zephyr-2006-Fusion-Milan-2006-2007-MKZ-2007/Components-Systems/Cylinder-Head-Temperature-Sensor/_/P-0996b43f8075c823 If you're sure the spark plug is okay, the next thing to suspect would be the fuel injector on that cylinder. Are you getting any other codes besides P0303? If you believe water got into the cylinder and you hydrolocked the engine, you should do a compression test. You may have physically damaged the engine. I had the codes reset after replacing coil 3. The plugs were replaced and it had run with the original coil for a couple days before fouling up again. When that happened the engine light came on and the code for cylinder 3.. At that point i put in the new coil and reset the codes. Now that i have wiped the code the misfire is random again. It did not misfire today yet.\ for me after 2 hours of driving around and about a 1/2 hr. of idling. I'm guessing it will come back. As far as water getting into the engine, i hope not. The old plugs showed normal wear with 80k on them when i took them out. The water was standing about 1/2" of it on top of 2 plugs and that HTC sensor (thank you!). Would that sensor. I was just wondering if that sensor may be effecting things now or not with the misfire. 0 Quote Link to comment Share on other sites More sharing options...
FusionDiffusion Posted February 5, 2012 Share Posted February 5, 2012 Okay, so plug #3 was fouled? Did you clean the plug before putting the new coil on #3? Unplug the HTC sensor connector and make sure it's dry. Also measure the resistance as I indicated so you know if the sensor is good. Measure it with the engine cold and right after you've driven the car (hot) and report the values. It's possible the CHT sensor could cause a misfire if the PCM is adjusting the mixture enough to create a really rich or lean condition. But usually you will see a code pertaining to the CHT sensor. When you run the engine is the temperature gauge on the cluster getting up to the middle of the normal range? Also, what were the circumstances that allowed the water to get on top of the engine? Did you leave the hood open and it rained, were you hosing off the engine, or did your drive through some water? I take it you got a CEL, read the code, went to pull the plugs, and discovered the water at that time? So you got a P0300 after the new coil, cleared the codes, and you currently have no codes or a CEL? 0 Quote Link to comment Share on other sites More sharing options...
cooldrums Posted February 5, 2012 Author Share Posted February 5, 2012 Okay, so plug #3 was fouled? Did you clean the plug before putting the new coil on #3? Unplug the HTC sensor connector and make sure it's dry. Also measure the resistance as I indicated so you know if the sensor is good. Measure it with the engine cold and right after you've driven the car (hot) and report the values. It's possible the CHT sensor could cause a misfire if the PCM is adjusting the mixture enough to create a really rich or lean condition. But usually you will see a code pertaining to the CHT sensor. When you run the engine is the temperature gauge on the cluster getting up to the middle of the normal range? Also, what were the circumstances that allowed the water to get on top of the engine? Did you leave the hood open and it rained, were you hosing off the engine, or did your drive through some water? I take it you got a CEL, read the code, went to pull the plugs, and discovered the water at that time? So you got a P0300 after the new coil, cleared the codes, and you currently have no codes or a CEL? I don't know if plug 3 was bad or not, i tend to think it was the coil because i changed all the plugs and only got the code when the engine light finally came on the day after the plugs being changed. But hey, i am not a mechanic. I rinsed off the top of the motor like a week before it all started going wrong, stupid me. I will try do your tests this week as time allow after work. Check engine light and code were before the new coil was in place but after plug change. I may take it to my mechanic and have him look for a mode 6 misfire as i'm not sure it has generated a code yet as there is no engine light yet. I have not had the codes read again yet. Thank you for all your valuable input, this is great. I need a code reader! 0 Quote Link to comment Share on other sites More sharing options...
Ruggybuggy Posted February 12, 2012 Share Posted February 12, 2012 Any time you have a missfire because of water contmination you have to replace the rubber boot and spring that goes from the coil to the plug. Make sure you have gapped the new plugs to spec. 0 Quote Link to comment Share on other sites More sharing options...
FusionDiffusion Posted February 12, 2012 Share Posted February 12, 2012 ^ This is good advice. 0 Quote Link to comment Share on other sites More sharing options...
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