Prius Gen 2 stumbling, cold start rattle, running lean? Blistered spark plugs, pinging when hot

oem plugs from a dealer?

 

there are a lot of cheap chinese counterfeits flooding the market. only dealers have secure supply chain from toyota

 

any trouble lights?

 

Can you take some pictures of the old spark plugs and upload them here?

Does your scanner show you the short and long-term fuel trims?

 

In whatever ECM data that the app can display. There are two values - short term fuel trim (STFT - it's a direct response to the Air-Fuel sensor. This value changes constantly as the engine runs), and long term fuel trim (LTFT - it's a learned value that can be different for various RPM & engine load conditions. It tries to keep STFT near 0).

Ideally both values stay near 0%. They can go "up" to around +20 to 25% (adding fuel by increasing the fuel injector on-time) or "down" to -20 to 25% (removing fuel) . More than 10% correction points to a problem. The ECM sets codes when fuel trims reach 20% or so.

Posted via the PriusChat mobile app.

 

I'd check fuel flow and pressure while delivering the flow, then restricted fuel return to see how far the pressure rises ..... this all has the basic symptoms of excessive learn burn ......

T1 Terry

 

When you say regular, do you mean 91 Octane? If so, use 95. On 91, you will get pinging under load. Using 95, it solves the pinging, and you should get at least another 100 km per tank. I get near 200 km extra on 95.

What do you mean by this? What restrictions are you experiencing?

 

What state in Australia do you live, maybe someone in the area can help you go through the various checks etc ......

The knock sensor should not allow the ignition to advance enough to cause detonation (pinging) but a very lean run will cause all the symptoms you have described, our ex taxi Prius suffered similar after a long rather "spirited" run with the stereo up so loud we couldn't hear any engine noises.

Turned out to be a blocked catalytic converter and blocked fuel filter that probably caused the lean burn that cleaned all the carbon out of the engine and exhaust, resulting in the blocked catalytic converter.

Being an Australian model, the fuel filter lives under the vehicle, roughly where the passenger seat (left hand side because we drive on the correct right side of the road) and available from the likely auto parts shops ....

T1 Terry

 

With 30+ posts under your belt, you shouldn't have any restrictions. I would contact the site admin (by clicking on the report button under this post) and request a review of your account settings.



[EDIT]
For the USA audience:
91 RON = 87 AKI aka R+M/2
95 RON = 90 AKI

 

The knock sensor does peg back the engine on 91 (RON), but it still will ping under load. Toyota says this is normal behaviour in the owner's manual as long as it only occurs under load and is not sustained for a long period.

This reduced performance is evidenced in less responsiveness (in terms of acceleration) and general sluggishness or less "pep", if you like, in general driving.

 

Over here we have E10, low octane fuel with a min 10% ethanol added, both the Prius and the Ford 6.8ltr V10 in our motorhome, love it .... and it is the cheapest by law ..... It sure keeps the fuel system clean and water free, generally around 93 to 94 octane, where the regular unleaded is as low as 89 octane, you really notice the loss of performance and fuel economy when using that stuff, but it never equates to better kms/$$ to buy 95 octane in either vehicle ..... the V10 already eats 40 ltrs/100kms, 95 octane would have to improve the full tank range by more than 100kms to justify the price ..... the improvement would not be anywhere close to that ......

T1 Terry