CX-5 2.0L - P0304 P0171 - Help needed please

yugrus

Contributor
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CX-5 GT
LTFT gets out of scale at 23% while spark advance is pulled to zero. It's choking, it can't burn all that fuel, that's what it looks like to me. It behaves like under huge load with no help from the transmission...
Another thought, SkyActiv engines are quite finicky when it comes to spark plugs. I've read that OEM plugs are the part of the system for indirect measurement of the cylinder pressure. I see that you're using Bosch plugs with multiple applications... Who knows...
How did you check for air leaks, did you use smoke machine?

It is a waste to throw parts at the problem, but in your situation there's not too many options.
Too bad there are less and less techs who know what they are doing, even at the dealer. Their hiring pool is the same as Midas'.
 
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Mazda RX-7
I think the timing being pulled is a result of all the knock. As I sweep the graph it starts at 43* and quickly drops.

I don't have access to a smoke machine. I have capped the brake vacuum port and visually triple checked all the hoses. This car isn't very old and the hoses are in good shape.

When I get some time I am going to try and thoroughly go through this procedure. Many I have done already.
http://mazdaman.x10host.com/SM352634/

Wondering if I can shut off injectors with ForScan???
 

yugrus

Contributor
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CX-5 GT
I'm sure I recall shutting injectors off with ForScan on my son's Crown Vic. It was a while ago, I can't recall now how it's done. Shouldn't be too hard. What are you trying to achieve with that though?
 
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Mazda RX-7
I'm sure I recall shutting injectors off with ForScan on my son's Crown Vic. It was a while ago, I can't recall now how it's done. Shouldn't be too hard. What are you trying to achieve with that though?

See if one being shut off has less effect than the others. Maybe another weak injector.

Honestly just swapping the whole rail over from a known good car would be more definitive. I'm nervous about the Teflon seals getting ruined. It requires a special tool to put them back on supposedly.... and they are 12 bucks a piece I think.
 
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GA prior 16 CX5 GT
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20 CX5 GT + Prem
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Mazda RX-7
There is a ion feedback system from the spark plugs, take a look at:
http://nema.club/2014wsm/service highlights/books/n6w01/html/id0140g0004400.html and
http://www.mcx5.org/spark_plug_inspection_skyactiv_g_2_0_-1154.html
make sure your plugs support this, you may need to put in Mazda plugs to make sure this is not the problem... Here is some of the theory
http://bmwmotorcycletech.info/ionization-current-sensing-ignition-susbystem.pdf

You nailed it!

The car came to me after new plugs were put in by another mechanic.

I got another CX-5 to start testing/swapping parts. Started with coils, then plugs, and noticed a big difference in the plug type in the working CX-5.

Plugs are $32 a piece at the dealer!

Be careful, RockAuto lists those Bosch Double Iridiums as compatible. THEY ARE NOT!

Thanks for all the help! Hopefully this post helps someone else.
 
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Mazda RX-7
Linking images from Facebook. Hopefully this works.

## Differences between the two plugs
23722261_10155243541658391_122913418364442954_n.jpg


## The cost and part #PE5R-18-110
23795425_10155243543413391_7664650857168692113_n.jpg
 
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2013 CX-5 6MT
The car came to me after “new plugs were put in” by another mechanic.
Hopefully the car behaves now!

You did some pretty good diagnostic work there.
It's a shame that the stupid dealer can charge a $127 "diagnostic" fee and doesn't put any actual effort into diagnosing.

You should have the G/F's dad show this thread to this other mechanic to prevent other poor soles from going down the same path!