Mechanical Help Mazda 3 | GTAMotorcycle.com

Mechanical Help Mazda 3

Rohan27

Rohan27

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Hey guys, so my friend has a 2006 mazda 3 GT (2.3L 4cylin). The other day we went to start her car but it was dead. We jump started the car and drove where we needed to go. Upon arrival we realized the cooling fan was not shutting off when we turned off the car and it did not shut off until the battery was completely dead. We drove the car home and disconnected the battery terminal. We reconnected the battery terminal and when we went to start the car again the car did not start so we boosted it but the car idles really rough and as soon as we disconnected the cables the car dies.

We had the car towed to the mechanic and they replaced the fan control module and the battery terminal. Now the car starts when boosted and stays running but it idles VERY rough and does not accelerate. It rolls forward when placed in gear at a slow rate but does not accelerate. The check engine light is on and the automatic transmission light is also on. Neither of which were on prior to all of this. The mechanic also informed us that there was no coolant in the car when it was brought in which is strange because it was serviced at Canadian tire not too long ago. The mechanic also informed us that the throttle body harness is corroded.

Whats the best route to take at this point? Any insight / advice would be HIGHLY appreciated. Thanks so much
 
When you plug in an OBDII, what error codes are being thrown with the CEL?
What's the history of the car? maintenance/multiple owners, etc?
 
Dont have OBD, ill ask the mechanic over the phone though

I'm not too sure on history. My friend is probably the second owner Maintenance has been neglected often times from what i can gather. Car is at 133XXX KMs

Spark plugs were changed (NGK iridiums) about 4000KMs ago, also ball joint and control arm were replaced

Car was also in a front end collision at some point with the first owner. Not sure of any more details.
 
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The cost of the throttle body replacement is going to be $475. Is this likely to fix the engine running issue?
 
You need to read the codes & go from there. Could be several things, most likely an electrical issue. Camshaft sensor, O2 sensor, etc
 
Rohan27 said:
The cost of the throttle body replacement is going to be $475. Is this likely to fix the engine running issue?
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You could try cleaning it up a bit before fully replacing it. Gunked up throttle body is a known thing with Mazda 3's and 6's. In fact there's actually a recall for the 3.0L in the Mazda 6.

There's a bunch of youtube video's on how to clean it up. While you're at it, wouldn't hurt to check/replace the engine air filter if it's never been done.
 
The problem right now is that the car is not even in running order. Could the throttle body be the cause for the rough idle and un-runnable condition?
 
If it was really run without coolant you might have more problems than can be diagnosed here.
 
Rohan27 said:
The problem right now is that the car is not even in running order. Could the throttle body be the cause for the rough idle and un-runnable condition?
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A MILLION THINGS could cause rough idle and 'un-runnable' condition!! You have a check engine light on, this means the ECU is throwing faults... which means the first step to troubleshooting is to get the FAULT CODES.
 
Rohan27 said:
....

Car was also in a front end collision at some point with the first owner. Not sure of any more details.
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Front end collisions can be irrelevant or a nasty thing to find out about. All depends on how much damage was done.

It's hard to know where even to start looking without codes - the mechanic should be able to give you a readout of what codes came up. Sounds like you've got some electrical gremlins under the hood.
 
mmmnaked said:
A MILLION THINGS could cause rough idle and 'un-runnable' condition!! You have a check engine light on, this means the ECU is throwing faults... which means the first step to troubleshooting is to get the FAULT CODES.
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I don't think that's what he wanted to hear
 
Rohan27 said:
The mechanic also informed us that there was no coolant in the car when it was brought in which is strange because it was serviced at Canadian tire not too long ago. The mechanic also informed us that the throttle body harness is corroded.

Whats the best route to take at this point? Any insight / advice would be HIGHLY appreciated. Thanks so much
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http://www.torontomazda3.ca/forum/forum.php

See if there is someone familar with these cars in the Brampton area.
 
So I've asked for the OBD codes and I've also gotten them to go ahead and look at the throttle body.

Ill post the codes once I have them.

Thanks guys.
 
The throttle body has what's called a TPS (throttle position sensor) attached to it. When you get on the gas, the butterfly plate inside the throttle body opens allowing air into the engine. The position of the butterfly plate is measured via the TPS and a value is sent to the ECU so that the correct amount of fuel can be delivered to the cylinders to keep the engine running smoothly. There's actually quite a few sensors involved in this process but we'll stick to the TPS for now. If the TPS is shot, then the ECU has no idea how much air is coming into the engine and can't send an accurate amount of fuel. You get stalling, rough idle, and lack of power. On some cars the TPS is simply bolted to the engine, and only the TPS needs replacing. On others, the TPS is a part of the throttle body, so when it fails, the whole unit needs to be replaced.

All that said, get the codes. And I agree with Subenz, sounds like you have some gremlins to work out.
 
I'm not a professional mechanic but two things stand out to me:

#1
Low or no coolant makes sense. It's not unusual for the fan to stay on for a little while after the car is turned off to allow the temperature to drop. In your case, I suspect the lack of coolant caused the fan to run for a long enough period of time that it drained your battery.

I'm not sure why you disconnected your battery at this point but it could explain your rough idle. When you disconnect the battery and re-connect it the vehicle needs to relearn it's air/fuel trim. There's usually a procedure for this and/or may require you to drive it around for a few days.

#2
Based solely on what you've mentioned so far... I don't know why the mechanic replaced the fan control module or the battery terminal without deeper troubleshooting. He said there was no coolant so the first thing he should've done was fill it up and then see if the fan issue persists. Instead, he replaced parts.
I can see a bad throttle body (or harness) causing your issue in Drive. If the throttle body is not responding then you can't give 'er gas because you can't supply the engine with air (you will still roll forward with the engine idling because the idle air controller bypasses the throttle body to feed a small volume of air to keep the engine running).

BUT... why would this suddenly be an issue along with the CEL and Tranny lights? I'm a bit suspicious of this but I don't know the whole scenario so I won't make accusations. It could be a coincidence... or maybe the overheating damaged the wire harness on the throttle body--even though the mechanic said it was "corroded".

You definitely need to evaluate the codes being thrown. Good luck!
 
AF4iK said:
I'm not a professional mechanic but two things stand out to me:

#1
Low or no coolant makes sense. It's not unusual for the fan to stay on for a little while after the car is turned off to allow the temperature to drop. In your case, I suspect the lack of coolant caused the fan to run for a long enough period of time that it drained your battery.

I'm not sure why you disconnected your battery at this point but it could explain your rough idle. When you disconnect the battery and re-connect it the vehicle needs to relearn it's air/fuel trim. There's usually a procedure for this and/or may require you to drive it around for a few days.

#2
Based solely on what you've mentioned so far... I don't know why the mechanic replaced the fan control module or the battery terminal without deeper troubleshooting. He said there was no coolant so the first thing he should've done was fill it up and then see if the fan issue persists. Instead, he replaced parts.
I can see a bad throttle body (or harness) causing your issue in Drive. If the throttle body is not responding then you can't give 'er gas because you can't supply the engine with air (you will still roll forward with the engine idling because the idle air controller bypasses the throttle body to feed a small volume of air to keep the engine running).

BUT... why would this suddenly be an issue along with the CEL and Tranny lights? I'm a bit suspicious of this but I don't know the whole scenario so I won't make accusations. It could be a coincidence... or maybe the overheating damaged the wire harness on the throttle body--even though the mechanic said it was "corroded".

You definitely need to evaluate the codes being thrown. Good luck!
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I disconnected the battery in hopes that I could just reconnect it when I needed to drive out again and start the car (dont have my own booster cables and didnt want to run around looking for some)

I'm not sure about the coolant issue, but the car was being driven regularly before these issues and the temperature gauge on the car was behaving normally (warming up and remaining at a stable temp)

The issue with the rough idle and all of that also did not start until this cooling fan issue.


To be honest I dont know if the mechanic checked for codes because when I asked for them he said its $120 to check. This is all at Scarboro Mazda.

The mechanic looked at it and charged me "straight time diagnostics" for the electrical wiring going to the cooling fan. After looking at it for 3 hours (what I was billed for), he recommended to replace the cooling fan assembly after which he attempted to start it and test drive it but the idle was very rough and the car was almost immobile.
 
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Here's a thousand dollar question: is your mechanic worth a damn, or is it some Canadian Tire reject???? You sound like you may not trust him.


If there was really no coolant in the rad (and not just the overflow reservoir!!!) then the car would've overheated and you'd at the very least have a cooked head gasket on your hands. Smoke? Burning oil and coolant? Funny smells?
 
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