Mazda 6 Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
Alright guys I'm stumped.

I'm running an 04 with the 2.3 in it. The car was starting, but idling up and down when it was cold, and until it warmed up it would misfire and surge whenever you accelerated, but once it warms up, it runs fine.

I bought one of the cam sensors because it was throwing the code that it was bad, but once I installed it, the car wouldn't start. I pulled the new one out and put the old one in and the car started but ran crappy, just as it had before.

I suspected the part could possibly just have been bad so I went and exchanged it for another one. When I came back and put the 2nd new sensor in, the car wouldn't start once again.

So I went back to square one and put the original sensor back in once again and proceeded to drive the car around once it warmed up. Is there something I'm missing? Even if the original sensor in the car isn't the problem, shouldn't replacing it with a brand new one leave the car running in the same fashion as before? I don't understand why it won't start at all.
 

·
Registered
Joined
·
370 Posts
I don't know why that might happen. I'm wondering if that is the original engine? If it's not, then maybe the part for it is different than the one you got. If the engine has been swapped then maybe it's a Ford part and not a Mazda part. When reading over some engine swap info I recall someone saying that the sensors on the engines are different.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #3
all stock

As far as I know the car is all original. I just bought the vehicle earlier in the fall and it has only started doing this since the weather has gotten cold. I have read all of the horror stories that people have run into with the P0340 code such as timing belts and all that fun stuff, but nothing explains why the car would smooth out. I also ran dry-gas through in order to try and clear any moisture from the lines.
I am completely stumped as to why with the new sensor installed the vehicle will not start. When i was explaining this to a mechanic friend of mine i said "Its like replacing a flickering light bulb and then losing power to the whole room, but putting the old bulb back in and the light be back."
 

·
Registered
Joined
·
370 Posts
Generally speaking, I believe that if a car smooths out as you drive it there is a vacuum leak somewhere.

This cam code and the sensor issue is strange. I don't know how else to explain the problem. Look on the original sensor for any markings that might identify it as a Mazda or Ford part.

Meanwhile, I'll search the forum for possible answers.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #6
Ill make sure to look into the possible vacuum leak possibility.

On the bright side I read that the longer you leave the battery unhooked the better it will relearn a part/sensor. I let my car sit with the sensor and battery unhooked for about 40 minutes and afterwards the car DID start and the CEL went off..... BUT the car's RPMs still bounce at idle and the original problems are present.

What else could cause these issues separately from what triggers the CEL?
 

·
Registered
Joined
·
370 Posts
I'm not sure, sorry.

I strongly encourage you to go to the 2.3L forum. In the search box for that forum, search on the code P0340. There is alot of info that might help you further.

Good luck and let us know what you find fixes it.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #8
Unfortunately most of the posts i found related to mine came up answer-less as well. I spoke with a mechanic the specializes in foreign cars and he told me that the problem I was having sounded like a faulty CRANK sensor. He claims that the car may not be equipped to recognize the CRANK sensor so it throws the P0340 CAM sensor code. Whether this is true or not I really have no clue.

The mechanic told me that as long as you eyeball about the right spot for the sensor you do not need the TDC pin the procedure calls for (in fact he said "In the 15 years I've been here I've never used one for a sensor.") So I unhooked the battery and then swapped the CRANK sensor out as well and my problems disappeared. The car runs fine once again BUT the CEL will occasionally come back on. I don't really know why because so far there's been no rhyme or reason for the circumstances that trigger it, but as far as I really care, the car runs fine.

I'm not experienced with this forum so I don't really know if there's a way to put this thread out there but I hope that it can help someone down the road before they take the car to a dealer and drop about $300 for a $40 fix.
 

·
Registered
Joined
·
370 Posts
Good job and glad that you're back on the road!

Overall, this whole thing makes no sense to me. The symptoms, the code, the way that it ran, etc,. But most of all the fact that the new cam sensor wouldn't work.

A faulty crank sensor affecting the cam sensor, I can sort of see that happening. No CEL for a faulty or intermittent crank sensor? Pretty surprising. Electrically they do share a common ground.

Anyway, you did a great job of keeping us posted on what fixed your 6 and by doing that you guaranteed that this one didn't go "answer-less."
 

·
Registered
Joined
·
2 Posts
Unfortunately most of the posts i found related to mine came up answer-less as well. I spoke with a mechanic the specializes in foreign cars and he told me that the problem I was having sounded like a faulty CRANK sensor. He claims that the car may not be equipped to recognize the CRANK sensor so it throws the P0340 CAM sensor code. Whether this is true or not I really have no clue.

The mechanic told me that as long as you eyeball about the right spot for the sensor you do not need the TDC pin the procedure calls for (in fact he said "In the 15 years I've been here I've never used one for a sensor.") So I unhooked the battery and then swapped the CRANK sensor out as well and my problems disappeared. The car runs fine once again BUT the CEL will occasionally come back on. I don't really know why because so far there's been no rhyme or reason for the circumstances that trigger it, but as far as I really care, the car runs fine.

I'm not experienced with this forum so I don't really know if there's a way to put this thread out there but I hope that it can help someone down the road before they take the car to a dealer and drop about $300 for a $40 fix.
 

·
Registered
Joined
·
2 Posts
Hi did you fixed your problem. I have the same issue in my mazda6 2004 and i cost lots of money for mechanics and they did nothing car is in same condition won't start can you please help me
 
1 - 11 of 11 Posts
Top