Exorcist wanted... My car is possessed

[TAS]

Let me start by introducing myself; my name is Todd and right now my beloved ride is named Lucifer.

It is a 05 Mazda 6 with a 4cyl automatic/ac

My son and I are in desperate need of assistance because have need to be in Wildwood NJ by Thursday night for a busy weekend. We are sponsored riders and definitely need to make a showing. The Mazda is a walking billboard so to speak so it needs to make an appearance as well.


The symptoms:

*Cold morning start can barely fire up and will hunt for the idle.
*Upon running temperature car accelerates fine (CEL lit).
*When I decelerate that's when things get funky... Tack will go to zero then
back up to original spot then repeat. The traction control dummy light is on
and the TCS light is flashing on and off.

I stopped be Auto Zone and the computer flagged the crank position sensor as being the culprit. This was replaced and still a no go... it seems to have gotten worse! I found this forum during a search and from the looks of it I have come to the right place! I have been overwhelmed over the amount of information there is on my car.

I keep reading that a lot of the symptoms could be because of the EGR valve not functioning properly. Could this be the culprit as well?

Thank you for taking the time to read all of this, the dealer option is out of the question because it is way too far away. Any thoughts?

At a loss in a sea of sensors,
Todd

 

[TAS]

This is what we haul on the 05. It's been a wonderful car and a great piece of transportation. Maybe I ask too much from it

 

[Blendercloud]

At first it sounded a bit like a cold idle switch. That switch detects the temperature of coolant and will adjust the idle up accordingly.

I don't even know what to think about the tach situation.

 

[8.5MS3]

when the tach goes to 0 does the engine sound like its trying to quit? sounds like an electrical gremlin. did you reset the ecu? if not try disconnecting the battery for about 15 min and see what happens

 

[TAS]

I had a mechanic also say something about the cold idle switch and he was going to look into it. Headed out now to reset the ECU...

Is there a throttle position sensor on this? What do you think about that?

Many thanks for the replies!

 

[TAS]

After resetting the ECU it seemed to be worse meaning that it stalled at lights and now wouldn't hold an idle at all. After more reading on this forum told me that the ECU was taking it's time to re-adjust so yes after about 30 minutes it idles fine. When the tach drops to zero I don't feel the engine trying to quit, and I tried to accelerate during the drop to find out if it had died which it didn't.

Is there any other thoughts on what could be the problem?


Thank you,

 

[TAS]

After renting a vehicle for the weekend not wanting to harm the motor any further, I have a possible route to the problem.



The mechanic who has been doing the work tells me that there is an internal cam sensor that has gone bad. This is located in the timing chain area on the face of the motor. Apparently they shorted out this sensor and it ran fine but this is going to cost in the neighbor hood of $1500 to fix.



Does this sound right? I feel about sick to my stomach right now.

 

[8.5MS3]

since its an 05 you could still be in the 5yr/60k powertrain warranty, provided you have less than 60k miles. also check for TSB's. Dealer would be required to fix it for free if it is.

a cam position sensor failure does sound like it could be a culprit.

 

[Blendercloud]

I don't know how much the sensor is itself, but that's a lot of money for what's involved to replace it.

 

[GiJoe]

That sounds a bit expensive. but the mechanic may have to drop the motor to change the sensor. but that may be the problem, as I firsts started reading the first post I was directed toward a fuel issue. but when you start talking about how many sensors these things have. I kinda get lost. lol

 

[TAS]

but when you start talking about how many sensors these things have. I kinda get lost. lol

I'm in the same shoes as you thats for sure after being used to driving old Jeeps. There was only 3 three things that where required to make these things go.


The correct term that I just found out was a variable timing phaser.

 

[Blendercloud]

The correct term that I just found out was a variable timing phaser.

Sounds like a Star Trek weapon.

 

[waldo_2001]

Does the car have a throttle posistion sensor (TPS). When I had a Saturn that went bad and the symptons were very much the same. I could tap the sensor and cause the engine to jump all over the place. Replacing it $150 area and all was fine. On Saturns it was located on the Throttle Body.

James H

 

[TAS]

As of right now the car is running fine due to the fact that the sensor is grounded out. This sensor is located in the timing chain area with the lead wires coming out of the top left of the valve cover. I am going to make an appointment for second opinion for the replacement of the sensor. I will have them install a new timing chain in at this point as well. Good idea?

 

[8.5MS3]

how many miles on the car?

 

[brandini]

timing chain is a PITA and an unneeded expense before 100K miles

as for gauges, sounds to me like a grounding issue

 

[TAS]

The car has 89K on it and that's the only reason I was looking into it.

New appointment is on Friday 8am and I elected not to drive it until then.

 

[Afroman]

This sounds a little dumb and maybe already looked at.... but this is from a car I had a while ago.

Are all the intake hoses and MAF/Temperature harneses connected?

My old car had a loose hose - Exhaust Gas Return - loose on the upper manifold - this cause the car to act crazy at idle (near stall) and run really crappy when it was first started up.

If its a loose hose after the MAF you car is getting way more air than its accounted for..... which would make it stall and run very lean.

If you got 15-30 minutes. Poke around your intake and top side of your engine. Look for loose hoses or even frayed wires or bad loose electrical harneses. Give everything a little yank to make sure they are snug.

Its quick and its free. So if everything is cool no big deal. If you find something loose --- great!