HELP, check engine lt.& check hibrid system. after changing plugs

Try ngk plugs.denso gave me knocking results

 

did you torque them properly?

 

They're the specified Denso plug? And where did you buy; wasn't there some counterfeits?

IIRC, Toyota changed the spec plug's "heat" range, from 20 to 16. But I think either would do.

 

Torque is 15 ft/lb with dry threads. Maybe 12 with anti-seize.

 

The Owner's Manual says Denso SC20HR11, but if memory serves, Toyota fairly recently revised that to (hotter) SC16HR11. Dealership parts department can likely confirm that.

 

Begs the question how was it running before touching the plugs? Also, I'd re-check all components touched during your plug change. Maybe something didn't get put back correctly...

 

Please keep us posted. I'm a big fan of twin tip denso plugs and run them in 2 other cars I own with no problems whatsoever. I considered getting them for prius if available. What is the specific part # you got? I need to do more search. Why would they work for most cars and not prius? Did you test them?

once i had a weird problem with denso iridium plugs in my boat, after countless problems, i switched to regular old fashioned copper/nickel plugs and no problems since. turned out when denso sharp (but single) tip iridium plugs got fouled, they were useless and no cleaning could fix them.

 

there are some other threads on people changing prius plugs using OEM ones and getting way lower MPG. not sure why prius is so picky about such a routine thing.

 

I bought the same plugs from RockAuto. Although, I haven't used them yet because my car hasn't hit 100,000 miles yet. There are two reviews on Amazon from Prius owners (2010 and 2014), so I thought these plugs should be fine.

There are also fake Denso spark plugs out there, so be careful.

 

The spark plug replacement interval is 120K miles (192K kms) or 144 months (12 years), the same as in the US.

 

Yeah focus, lol.

Seriously, even out of focus, that doesn't look good.

Still: why would this happen to a brand new plug?

How many miles, and have you ever cleaned the Exhaust Gas Recirc circuit, and/or intake manifold?

 

Ok thanks, maybe others will comment, all I can suggest is to check condition of the pipe between EGR valve and intake manifold, see how much carbon build up.

Shooting closeups like the above, your chances are better if the background is something like a blank/smooth wall, it'll force the focus on the plugs, as long as they're not closer than the close focus limit.

 

is the broken plug the same that was loose?
it's hard to imagine they came like that from factory or broke after short use. hopefully the broken tip didn't score the cylinder too hard. watch oil consumption now.

 

i bet those were were fake densos. i ordered a set of denso TT from ebay and got 2 different styles with slightly different description on the insulators. I got suspicious and compared to the original ones I purchased at brick and mortar store for my son's car (different size). there were subtle differences on box and print looked sharper on the originals. The metal finish was slightly different on the plugs with fakes being shiny chrome plated, densos semi mat with fine machining groves.