Turbo, followed by engine failure

[Aja1732]

Hey everyone,
So my 2010 Mazda Cx-7 GT (77k miles) decided to break on me the other day. The closest place I took it too said that my Turbo failed and that caused the Timing Chain to mess up which caused internal engine problems. Now let me explain what happened.

On interstate, accelerating, all the sudden a high pitched whine that changes with RPM, got off at next exit. Once I stop whining stopped followed by a crunch when accelerating. Pulled into a AAMCO Transmissions. They diag'd it at basically said I would need a new turbo and a new/used engine replacement.

As of right now I have it being towed to the nearest Mazda dealership, to see what they think. Now my question is, 1.) Could that actually cause that much damage with the turbo failing? 2.) Can it not be rebuilt? or is that cost prohibitive? 3.) If I was to find out that it could be rebuilt what would you change on it? Besides the MS3/MS6 Turbo change, I know I will definitely do that just because of how prone the current CX-7 Turbo's are to failure.

Thanks for reading.

Its been a fun few days. Wasn't expecting it to happen, but then I guess you never are. Also any advice would be appreciated. I love the car. Its fun and comfortable, plus I still owe on the car so I'm planning on keeping it for a bit.

[mazda62006]

It really depends on what the failure was with the turbo. I guess it could cause engine damage. Also as for a rebuild, you really won't know until someone pull the engine apart to see what happened. I would rather rebuild if possible since you do not know the history of a used engine. Good luck

[Aja1732]

So just got a call from the dealership and there diagnosis is much better then the first one. They said that I only needed a timing set and new turbo. So I have enlisted some help from a mechanic friend of mine and I am planning on doing this myself. My question is since I have the chance what should I replace the oem turbo with? I know that if I go with a different turbo I will have to do retune the engine. Any recommendations on parts would be greatly appreciated.

Thanks!

[shamie]

So a transmission shop diagnosed an engine that some Mazda dealers can't even diagnose correctly? Good you got out of there and I hope you didn't pay them for their "advice".

As for the turbo just go VIP here and buy a used turbo for $100-200 and call it a day. The turbos on here will probably be from a speed and not a CX7, but should work just fine as a direct replacement.

[Aja1732]

I think I'm going to go new on the turbo. Probably just one online for it somewhere, unless there is a benefit to going with something like the BNR S1 or CS for a daily driver. Also is there anything else I should look at replacing while I am doing this? Like I said I know I will need to tune it for the larger turbo. Thanks again for the help. I wasn't expecting something like this to happen when it did, but kind of excited for a reason to replace it with something better to make the car a little more fun.

[Aja1732]

So I picked up a used K04 from the classifieds, as well as ordered a Versatuner with cable, which should be here hopefully by the weekend. I've been reading about the tunes and learning to understand them. My question, if I am going to replace my timing chain, should I also replace the VVT? I'm finding quite a few basic kits for that, but with the problems I am having, would the VVT be the cause? I know I had the recall done on it, but that doesn't mean anything at this point. Also while I am doing the Chain, what else should I replace? Any pumps, etc?

[andale927]

I would go with the edge auto VVT kit, might as well replace everything while you are there:

Mazda OEM VVT Replacement Kit Mazdaspeed 3 / Mazdaspeed 6

[Aja1732]

That's what I was thinking. Just doing the whole thing and then not having anything to worry about. Thanks for that link, appreciate it!

[Aja1732]

Thanks again for all the help everyone. One last question, I've been trying to find info on how to do the timing chain and whether or not I will have to remove the engine for it. Anybody have any directions or links I could take a look at for it? TIA

[Aja1732]

So in the process of getting the turbo out I decided to look at the internals to see what I'm looking at with the timing chain. Well timing chain is a little loose, however my big concern in looking at the engine is the gunk and oil sludge built up. Anyone have any recommendations on how to clean that out? Before I get started on taking apart the serpentine belt and timing chain.

[Alpha Wolf]

If you have a lot of sludge and hardened oil in your galleries, that is due to not doing oil changes at the proper intervals or using the wrong oil or both.

Not much you can do if you are not rebuilding the engine. If you use any kind of cleaner inside the top of your engine you will need to change all of your oil and filter to assure none is left when you start it.

[Aja1732]

Yeah, I ended up draining all oil and and coolant, and took the valve cover off and did a cleaning of the camshaft area using a kerosene spray. Evaporated pretty quick but broke up the sludge and everything is nice and clean. Hopefully once I get the time case off it won't be that bad. Figured out that to get the timing case that I have to remove the hydraulic motor mount and use a jack under to support it at the oil pan with a 2x4 or something similar to spread the weight out. This will hopefully prevent any damage to the oil pan. Once I got done cleaning the camshaft area I had a hose connected to a shop vac and sucked up all I could. Good news all that was left in the shop vac was the dried oil dust/small chunks. Learning as I go. But so far so good. Turbo is almost off after finally getting the exhaust manifold off. Got all parts and hopefully will have it done this weekend. Will let you know how it goes.

Edit: I'll also get some pictures up of what it looks like after the kerosene bath. Haha

[Aja1732]

I will also work to get a little guide together to better explain what all I did for people in the future that have similar issues. I'll try to get as many pictures up as I can, maybe in an imgur gallery or something. It might not be the 100% right way, but so far, my way has worked.

Thanks again for all the input and suggestions.

[shamie]

There is a VVT how to on here.

[5doorsoffury]

HOW-TO VVT
Best guide eva

[Aja1732]

I was quite surprised at how easy that was to replace once I had everything off. Thanks to the wonderful rain, I haven't had a chance to work on it since Saturday. Just have to put everything back together and put fresh fluids in. Only PITA was getting the last few bolts taken off from the turbo. Everything else was relatively easy, with the write set of instructions.

[Aja1732]

So good news and bad news.

Bad news first, after getting the new turbo and timing kit on, I found that the exhaust camshaft had cracked on the end. So now it's going to need a rebuild.

Good news is that it was relatively easy to get the engine out and dropped off at the machine shop.

I'll keep it up to date.

[Aja1732]

After a few months of working on the vehicle off and on finally at the point where I will have it finished this weekend. Once running I will use the Versa Tuner to take into account the turbo from the Mazda speed. Question for you though, since the engine has been rebuilt. Once all new fluids have been added, is there anything I should do prior to the first start? A mechanic buddy recommended that I try turning it over without the spark plugs firing to get the pumps and everything moving. Any input would be great!

Thanks!

[SSinstaller]

Cranking while holding the gas pedal at WOT will turn off the fuel and let you get the oil circulating before it fires up.

[Aja1732]

Thanks for that! Appreciate it! Can't wait until I get it back on the road.

[Fstrnyou]

Be sure you don't forget to hook up your throttle body wiring. I left mine off by accident and went to turn the engine over while WOT to circulate fluids and it started right up. Throttle pedal did nothing, obviously.

[Aja1732]

Originally Posted by Fstrnyou Be sure you don't forget to hook up your throttle body wiring. I left mine off by accident and went to turn the engine over while WOT to circulate fluids and it started right up. Throttle pedal did nothing, obviously.

Haha thanks for the tip. I'll go through and double check all my wiring to make sure.

[Aja1732]

So I have everything put together. Now the issue is that is runs if I use the accelerator while I start it and keep it above 1500 rpm. If it falls under it dies. If I keep it going and I put it in drive it stays idling but is very rough.

Now here's the weird thing, no CEL and the engine rpm above 1500 is smooth. Under is really rough. Could fuel left in there for 6+ months cause that, since it's premium? Any other ideas? MAF is clean. Seems like an air or fuel issue. Also I read something about a relearning procedure for idling?

[Thor Hammer]

Idle issue could be a few things. Check for vacuum leaks and toss in some fresh fuel if the tank is relatively low. Maybe you just forgot to hook something up? Check all your grounds as well. Particularly the one on the fuel pump.

[Aja1732]

So good news. Got the car up and running, ended up having a vacuum leak between the turbo and engine. So bad news, I think I damaged the new(used) turbo when it originally wouldn't idle. The turbo under any load makes a noise that sounds comparable to a weed eater. I'm assuming bearings or something went bad. Any input on that would help.


If the turbo is bad, then I'm looking at either the BNR S1 or the CS turbo. I'm going to compare the two hardware wise when I get the chance this weekend. The S2 for $100, says I have relocate the boost control solinoid. Still running stock everything but do have versatuner so ready to tune as soon as new turbo is in. Gotta google-fu comparisons between the turbo and see if it's worth the upgrade.

[Fstrnyou]

The CS turbo is between the S3 and S4.

S1 is comparable to stock.

[andale927]

If I were you I would install some sort of oil filter before your turbo oil feed with the new turbo. That turbo was definitely good and it is pretty unlikely to be damaged by an idle problem, you might have some debris in your oil from your previous issues.

Sent from my Nexus 6P using Tapatalk

[Aja1732]

Well I replaced the oil cooler and cleaned the lines out prior to reinstalling, figuring that would take care of it I have no doubt it was good. I probably jacked it up some how. I'll take a video of it when I get home reving and post it here. Get your opinion on the sound. Doesn't seem to effect performance at all. Mpg is better than what I was getting. Drove it for 30 miles and it started shortly after mile 3 or 4. No stuttering or issues. Just the noise. I'm just afraid of it having the same issue and causing another engine failure if it goes bad, that's why I'm thinking of a bigger turbo.

[Aja1732]

After much tinkering and just running the car around the neighborhood it seems that the loud turbo noise is fading. Don't know if that's good or bad. Haven't noticed any strange rev jumps or engine stuttering.

Then I went ahead and used VT and tuned the engine with the 93 octane, and wow what a difference in drivability. Also I forgot how well the car handles and rides vs the 2013 Outback I've been driving. So much better and more controlled. If the noise goes away I will stick with the turbo for the time being. Until I get a bug to do something else. TBH, I'm burned out working on it after so long. Haha.


Thanks to everyone that posted. It really helped out and I really appreciate it!

[Aja1732]

Well after a year of issues I've finally gotten it to the point where it's drivable. In Aug I had had enough and took it to the dealership after numerous issues communicating with the pcm they finally replaced it with a new one. The one code that keeps coming back regardless is p0012 (intake cam over retarded). I had them install a new timing chain and retime the engine which did not fix it. It keeps coming back after 30-40 miles of normal driving. The one thing that hasn't been replaced is the camshaft position sensor. Would I be smart in replacing or trying to clean it? It's not an expensive part and at this point I would rather replace it. Any other ideas if timing and vvt was replaced at dealer? I've had it back there numerous times and they have done a lot of work on it (new cluster, pcm, fuel pressure regulator, and ocv filter). This where I'm at. I'm driving the car on slow slide just in case. Any recommendations would be extremely helpful. Thanks!