High Mileage Mazda 3, Engine clean, oil for long term

[IndyIan]

I guess timing chain wear/stretch does tend to retard timing a little bit, but I've never seen numbers for it. VVT kicking in at the right rpms still?
I was messing around with my alternator so I had the battery disconnected for a while, and then by chance, I had 89 octane in the tank when I got the car back on the road, so I think the ecu relearned to run on the 89 and the car felt more peppy for a while until I went back to 87 octane.
Maybe try a tank of higher octane and reset the ECU, see if something is causing the engine to pull timing?
Try an italian tune up, a dozen WO pulls from 2500rpm to 7000, and engine braking down in 2nd gear might clear some carbon out that's causing some ping and timing pull?
How is your air filter? With no oil burn, your cat is probably good.
Feel all the hubs and brakes after driving. I had a brake drum dragging a bit which took me a while to notice

 

[BISCUT]

For oil I wouls simply run an OCI of HPL. Fuel filter seems like a solid place to start figuring out the issue.

 

[kschachn]

I also plan to check the ignition coils. No codes but it is possible that one or more are producing too little spark.

How do you check those for too little spark?

 

[SubieRubyRoo]

Coils never. They too are getting to the end of their expected life. I will be testing spark length and color to see if any are underperforming. Will replace as needed.

Don’t waste your time and all those extra trips to the parts store. Do all 4 and be done with it; Ford coils especially are notorious for one going bad, you replace it, and two weeks later you drop another. One trip, one cost, zero doubts. And don’t buy them from fleabay

 

[Johnnyz2]

How do you check those for too little spark?

With a tool like this: https://www.amazon.com/gp/product/B0DC9XTH8V/ref=ox_sc_act_title_4?smid=AY7ST2XRPXMUZ&th=1

Really you can't check to a spec, but you can see if one or more of the coils has less energy (shorter maximum spark, different spark color) than the others. Then replace the weaker coil. If all were bad, there's no way to tell with such a tool.

 

[Johnnyz2]

Based on some of the comments, I just cleaned the MAF. By eye it appears clean, same when viewed with with a low power magnifying glass; however, one of the two resistors wires are more reflective. It appears to have a bit of abrasion on it when viewed by eye and with the magnifying glass.

Trying to photograph it was difficult and the 5x cell phone lens is not super sharp. Combining that with zooming in on the file and I'm not certain whether it is actually still dirty or there's camera/photo issues. The top resister in the photo is the more recessed one and the one that appears to have some abrasion on the wire.

I guess there's another possibility and that is both are dirty but the shinier one is less dirty.

 

[Johnnyz2]

Here's some photos looking in through the oil fill cap. While this is not an area of expertise for me, considering this is the end of an OCI, I'm guessing it is pretty clean. Is that the correct assessement?

 

[Titan]

Here's some photos looking in through the oil fill cap. While this is not an area of expertise for me, considering this is the end of an OCI, I'm guessing it is pretty clean. Is that the correct assessment?

Yep, "pretty clean" is what I'd call it considering the mileage. Not perfect. And it wouldn't matter if at the beginning or end of an OCI. That doesn't change much (unless you have a "cleaning" ongoing, such as with Valvoline Restore and Protect, or perhaps High Performance Lubricant oil with it's ability to clean).

 

[IndyIan]

Here's some photos looking in through the oil fill cap. While this is not an area of expertise for me, considering this is the end of an OCI, I'm guessing it is pretty clean. Is that the correct assessement?

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Yep, whatever you've been doing for oil is certainly good enough, in terms of varnish/cleanliness. But does the cam lobe look a bit weird to you? Worn through the hardening layer on the tip?

 

[Urshurak776]

I don't like the look of this:

 

[Johnnyz2]

I don't like the look of this:

Yeah, that does not look right. I won't be able to look at it again until tomorrow; but, that's now at the top of my weekend list.

 

[katnapped]

Since OP is kind of in the same ballpark of what I'm chasing on my 3, what would cause the computer to be raising the LTFT (further positive) the more it's used in a given day and why is it often adding even more on a hot restart (ex. starts at high single digit positive LTFT, STFT subtracts some of it when the computer gets into closed loop on a hot restart, sweeps past zero and ends up adding to it within 10-15 seconds). It will end up dropping back somewhat after driving it for a few minutes.

 

[ka9mnx]

On your MAF. One of the sensors is naturally darker than the other. They both look contaminated.

Have any of the O2 sensors been changed? You should be on your third set by now. O2 sensors have a habit of getting "lazy" as they age.

 

[Tortuga]

I just picked up a 2005 vehicle with the Mazda 2.3 MZR/Ford Duratec engine. It’s been in my extended family for quite some time and reasonably well taken care of. My family member said it was leaking and possibly burning some oil. I cleaned the undercarriage really well and will monitor that to see where any potential leaks are.

I changed the oil and noticed there was no washer/gasket on the oil plug and that appeared to be one of the leaks. I put a crush washer on there and refilled it with 20% HPL Engine Cleaner 30 and the rest with Valvoline R&P 5W-30.

I also cleaned the MAF and put a bottle of Regane fuel system cleaner in the fuel tank. It seems to be running a lot better now. Probably due to the fuel system cleaner and higher octane ethanol free fuel I refilled it with.

Here are a few photos of the oil fill cap area at 148k miles.

I'd go with the Valvoline R&P. It’s cheap at Walmart and there's an easy $5 rebate via texting a photo of your receipt.

 

[dubber09]

I think I'd start with cat and O2 sensors checks. Lazy O2 sensors may add to trim and reduce responsiveness. Check live data.

 

[Johnnyz2]

Well, I had hoped that what was shown in the previous photo was actually a reflection of the opening. No such luck. Here's a new photo.

When this was taken it was still too warm to touch for long. So, I'm not certain whether what is visible is large enough to be felt. Later when it is cool, I will check again and report back here.

 

[6.7 CTD]

On your MAF. One of the sensors is naturally darker than the other. They both look contaminated.

Have any of the O2 sensors been changed? You should be on your third set by now. O2 sensors have a habit of getting "lazy" as they age.

I think I'd start with cat and O2 sensors checks. Lazy O2 sensors may add to trim and reduce responsiveness. Check live data.

Agree, O2 sensors would be getting attention long before injector replacement. When an O2 sensor does not have the ability to perform as it should, LTFT’s can increase.

 

[Johnnyz2]

So, now that the engine is cooler, I'm certain that the cam is very smooth to the touch despite appearing to have a visible sideways wear.

 

[BC1]

6% fuel trim is fine. The computer is still in control. Any parts changed will most likely be of lesser quality than the originals.

 

[ka9mnx]

With things critical like O2 sensors, I go with OEM.