New project in the family(08 Mazda3)

Hey guys,

Long time no see,

Scored a sweet deal on an 08 Mazda3 Grand Touring from my wife's cousin. They only had it about a year and a half and it was buy here pay here car I think, or at least a corner lot car dealer type place. I had recently picked up an 85 RX-7 project for my youngest son and I to mess with, and eventually be his car. However it isn't a great year round car for New England, and probably not the safest car for a teenager, so I wanted to find a more modern car for him. Stumbled on this deal as my wife's cousin ,and her husband are getting two brand new leases on Subaru's. I inquired about the Mazda3 that had been sitting for at least 6 months, and she told me they were going to trade it in. I asked how much they were getting for it, and offered to buy it from them instead.

They had stopped using it because it was running poorly, and their repair shop said that they didn't really want to work on it anymore. Not sure why, or what was/is really wrong with it. I was told that it was running rough, and they parked it to share the one good car they had left. I went over to their house on Friday after work with a jump box because I was made aware that the battery was dead. Arrived to a really nasty looking battery with that white fuzz all over it. Tried my jump box to no avail. Tried jumper cables to no avail. Went back over on Saturday to remove the battery for a core, and go to a local Interstate battery and buy a refurbished battery for cheap. Went over on Sunday, cleaned the cables, installed the battery, and it fired right up. Made some clacking noises at first, and was a bit shaky, but smoothed out eventually. Still had a bit of a skip to it though. Aired up two of the tires, took it for a spin around the neighborhood. All seemed fine once I got the rust off the rotors. Acceleration was super smooth, but it went okay. Had her follow me home in my Sienna, removed the plates from the Mazda, and gave her a ride home.

Later that evening I am showing it to a friend, and investigating things more. Popped the trunk, and lifted the carpet to see the spare tire. Well has a significant amount of water in it. Popped the rubber plug, and drained the water. Popped the hood, and the engine cover to find a mouse nest made from the white insulation on the underside of the cover. Notice some wiring that the loom has been removed exposing the wiring, but looks like humans did it instead of rodents.  No check engine lights, but definitely a skip in the idle, and acceleration. Power door locks seem to have a mind of their own, and the fob(non-Mazda fob) seems to make a beep sound come from the car, but the doors don't lock. However if you open the door the horn starts blasting on and off like an alarm. Needs a bit of TLC, and a good detail, but overall it seems like a good car. Oil, and coolant look fine.

Not sure what I've got myself into. Any words to the wise on things to look for? While I was getting coolant for my Sienna I asked the parts guy for spark plugs fro the Mazda, but they didn't have any. I figure plugs won't hurt. 118k on the clock, but it seems it was not well maintained, but also not necessarily abused.

Aftermarket alarms/fobs suck.  Hunt around the steering column or fuse box areas to see if you can find the "alarm box'   Mostly so you can get a brand name and then try to source a wiring diagram, instructions and parts list for the unit.  Not so that you can save the alarm but so that you can safely defeat/remove the alarm. 

I've had several of these for years.  They are pretty solid overall.  At that age/mileage check over the suspension well, it is probably all original and wearing out.  The motor mounts are also probably worn, with the pass side mount having lost all of its fluid.  In good shape they are fun to drive and there are plenty of upgrades available. 

Shuffled the car around in the driveway this afternoon to do a few things. While moving it back to where it was parked, it seemed to be running more rough than before and the check engine light is now illuminated. Of course I can't find my obd dongle now. Doh!!! 

Located dongel. It was still plugged into my oldest son's Vibe. Doh!! 

Which engine is the Grand Touring, the 2.0 or the 2.3?   I've got an '08 with the 2.0.   Apart from a basic service (NGK plugs & some filters) - if a mouse has been under there, check if any on the inlet ducting has been chewed on.  Also check the loom going into the MAF, the cables can fracture inside the insulation (give it a wiggle and see if things improve).

As Sonic said, engine mounts wear out and so do front strut mounts/bushes/dampers/springs.  The big passenger side mount fails constantly, but be wary of aftermarket standard mounts like Anchor etc, they can last up to around a year, or start to collapse after a month or two.  You can get "upgraded" mounts, but NVH goes up, or go fill them with whatever rubber/silicon etc takes your fancy, but it will vibrate like hell.  Next time I'm going to go for an OE Mazda one.   The lower torque mount can be changed to an E-Focus mount (noting you need the corresponding horizontal bolt) which is an improvement over OE Mazda, without the NVH of aftermarket.

Let us know what the OBD2 reader says..

Grand Touring (highest trim level) makes it a 2.3.  The 2.0 was only in the lowest trim levels

John Welsh said:

Grand Touring (highest trim level) makes it a 2.3.  The 2.0 was only in the lowest trim levels

Ok, thanks John.  Lowest trim levels and Peru .  The 2.3 didn't make it down here, the 2.0 "Sport" was the highest spec, the lowest spec got the 1.6 ZM-DE lump.

Mazdax605 - being a 2.3, add in the PCV to that list, apparently they are more temperamental..

Here's what my cheap Bluetooth dongle found. 

Many videos come back when searching these codes:

https://www.youtube.com/watch?v=7qm8-wFW51Y&ab_channel=Themechanic

https://www.youtube.com/watch?v=1euFBytQ_6E&ab_channel=JoDaddy%27sGarage

$23 via Amazon

If you have to remove the intake manifold for any reason, do Future You a huge favor and replace the PCV hoses under the manifold.  There is one big fat one with an elbow that loves to split and cause a huge vacuum leak.

Intake manifold R&R sucks unless you have done a lot of them, avoid building this skill by preemtively dealing with that hose.

Anyone have an idea how the intake manifold runner could affect how the engine is running? Just trying to wrap my head around how an intake runner (valve?) affects idle, low speed engine operation. Or is this part of a larger issue? Will I likely find other problems like ignition related stuff once I sort this out? I guess I can only go on what the OBDII scan tells me at this point, correct?

Mazdax605 said:

Anyone have an idea how the intake manifold runner could affect how the engine is running? Just trying to wrap my head around how an intake runner (valve?) affects idle, low speed engine operation. Or is this part of a larger issue? Will I likely find other problems like ignition related stuff once I sort this out? I guess I can only go on what the OBDII scan tells me at this point, correct?

Here is a quickly googled answer on the "WHY" of how a bad runner affects engine.  Also, see the videos I posted which show how to test if your switches work or they don't (clicking sound with test wire.)  

The intake manifold runner control is an engine management component that is found on newer intake manifold designs. It is usually a motorized or vacuum actuated unit attached to the intake manifold, that controls the opening and closing of butterfly valves inside of the intake manifold runners. The unit will open and close the butterfly valves in order to provide maximum manifold pressure and flow at all engine speeds.

While an intake manifold runner is not necessary for engine operation, it does provide the engine with increased performance and efficiency, particularly at low engine speeds. When the intake manifold runner control fails, it can leave the engine without the increased performance, and in some cases even reduce performance. Usually a faulty intake manifold runner control will produce a few symptoms that can alert the driver of a potential issue.

1. Difficulty starting the engine

One of the first symptoms of a faulty intake manifold runner control is difficulty starting the engine. The intake manifold runner control is usually positioned when the vehicle is started. If the unit malfunctions, it may not position the butterfly valves correctly, which can lead to difficulty starting the engine. The engine may require more cranks than normal to start, or may require multiple turns of the key.

2. Engine misfires and decrease in power, acceleration, and fuel economy

Another symptom of a potential issue with the intake manifold runner control is engine performance issues. If the intake manifold runner control has an issue it can cause the vehicle to experience engine performance issues such as misfires, a decrease in power and acceleration, a decrease in fuel efficiency, and even stalling.

3. Check Engine Light comes on

An illuminated Check Engine Light is another symptom of a possible issue with the intake manifold runner control. If the computer detects an issue with the intake manifold runner control position, signal, or circuit, it will set off the Check Engine Light to alert the driver of the issue. The Check Engine Light can also be set off by a wide variety of other issues, so having the computer scanned for trouble codes.

Nice score! The Grand Touring 3's are really nice cars. 

I echo what Sonic said: I'd replace all of the suspension bits and the engine/trans mounts before tossing the kid the keys. Parts are cheap for these, and they are super simple to wrench on. 

On the intake thing... I'm wondering if replacing this doo-hickey will fix it:


These usually go first, but there's also a physical tumbler that can lock up. I used to have one of those brand new in my garage, but I think it left during the last GRM New Year's Game. D'oh! They are cheap and available on Amazon, as posted above. 

I watched the video on testing the solenoids. I plan to do that next. Hopefully that is the problem, and I don't have to dig deeper into the intake manifold. 

New issue I found last night. The key fob doesn't seem to really work(like I mentioned before), and the one key we have doesn't work in the drivers door, but does work in the trunk/ignition switch. I wonder if it's possible to get the proper Mazda Fob, and program it ourselves rather than have to involve the dealer. I'm going to look for what might be an aftermarket alarm system in the wiring.

In reply to Mazdax605 :

You might check to see if Forscan can program those keys.

In reply to Mazdax605 :

Driver's door and lock...  Mazdas of this era should have vin tags on all body panels.  Looking for these tags.  Is the driver's door the original door?  Look close to see if the driver's door has a different vin on its tag implying used JY door.  This could have been done before they bought it off Buy-Here lot. 

Theory: driver's door has been replaced but lock cylinder was not corrected.  Shoddy work solution was to add aftermarket fob/clicker so you don't need a driver's door key.  

Or, if door seems to be original, a common issue...most people spend years entering their car via fob/clicker.  Therefore, the door tumbler gains years weather/road debris making the key unturnable.  If so, give it multiple treatments of penetrant/lube of your choice.   

Hard start, stalling and uneven throttle response (symtoms of a bad runner) as all good reasons why your people stopped driving the car as it became "unreliable."  I think the answer will be in the "test-wire-ing" of the current unit.  

Got my son an '09 Mazda3 Touring a while back as well.  Nice little car.  I replaced the suspension and passenger motor mount on it but otherwise it's a good driver.  Fairly easy to wrench on.  

Okay, update time:

Finally got to checking the intake runner solenoids today. The ones on this car are slightly different from the ones posted above and in the videos linked above. The solenoids on this car sit directly on the plastic intake manifold. 

In testing them one clicks and the other doesn't. I'm probably going to replace both. 

Beyond this, everything on the engine in this car screams its been replaced by a salvage yard engine. I come to this conclusion because of the yellow paint pen markings all over different parts of the engine. Do you guys agree? 

Yup.

So, JY engine and solenoids look different than expected...correct engine? 

Could it be a Ford 2.3L, not the Mazda? Does that matter? 

Being Grand Touring it should be 2.3L. The lesser trim got 2.0L. Could this be a 2.0L?

John Welsh said:

So, JY engine and solenoids look different than expected...correct engine? 

Could it be a Ford 2.3L, not the Mazda? Does that matter? 

Being Grand Touring it should be 2.3L. The lesser trim got 2.0L. Could this be a 2.0L?

I don't know the answer for this. However when I go on rock auto to check for the solenoid it shows this style for 2008. Maybe there was a mid cycle change? This car has an 07/07 build date. 

In reply to Mazdax605 :

I'm just making guesses. 

Those solenoids look exactly like what came on our 2007 2.3.   That is a Mazda intake manifold too, as the Ford versions didn't use the dual plane manifold from what I have seen, but that's mostly the later 2.5s that I know better.   More sure does look crusty though. 

Sonic said:

Those solenoids look exactly like what came on our 2007 2.3.   That is a Mazda intake manifold too, as the Ford versions didn't use the dual plane manifold from what I have seen, but that's mostly the later 2.5s that I know better.   More sure does look crusty though. 

You know, New England living and poor owners.