[stevewa]

After several months and over 8000 miles we got the dreaded christmas tree display in the Prius this evening. This time, the engine ran for a few seconds, then shuddered and stopped. After two more tries with the same symptoms, and swapping circuit opening relay with another like part, I called Toyota Roadside assistance who helpfully told me my coverage had expired (great way to find out). They offered to arrange a tow for me, but I decided to call my insurance to find out what options I had with them. In the meantime I tried again and the engine started and ran. Drove home, hooked up the OBD scanner and retrieved a P3191 plus a pending P0300 (multiple misfires detected).

It seems unlikely that the relay is the culprit this time. I'm looking at a couple of possibilities:

1. bad or damp fuel -- car has not been refilled since 10/29 and is at half a tank according to the guess gauge. Could be some moisture in there...

2. Fuel pump/tank.

According to the relevant TSB our VIN already has the updated ECU so it seems unlikely that replacing the computer will do any good.

Dealer is unlikely to be of any help at the present so I've cleared the codes and we will put some fresh gas in tomorrow, then watch for signs of any more trouble.

Anyone with similar experience in the "classic" Prius I'd like to hear from you...

 

[tochatihu]

misfires

Besides the things you are already trying, you might put some fancy fuel injector cleaner in the fuel tank, and either a spray or a liquid/swabable cleaner onto the throttle butterfly. I read in the Yahoo Canadian group that butterfly soot actually can set the misfire code.

DAS

 

[Sanny]

Re: misfires

I read in the Yahoo Canadian group that butterfly soot actually can set the misfire code.

Hmmm... butterfly soot. Is that like "frass"? And everywhere the Monarch went, his sooty foot he put...

 

[mrv]

The engine misfire codes can often be found with using high-octane gasoline, or driving over very bumpy (like cobblestone) roads.

The generic P3191 engine can not start code has several possibilities. TSBs that cover it:
EG011-03 (with P3101, circuit opening relay/ECM/fuel tank)
EG050-04 (incorrect oil or oil overfill)

and yes, soot build-up on the throttle body butterfly (supposedly visible under the engine air filter) is also known to cause the P3191 code, and there is a Canadian equivalent to a US TSB on it.

 

[stevewa]

Shot some throttle body cleaner around the butterfly, there was some dirt buildup there. Looks like the whole air cleaner assembly needs to come off to really get in there and clean it, though. Ran like crap the first couple minutes after digesting the cleaner, but seems OK now.

Just put a can of Techron in with some fresh gas, we'll see what happens.

 

[philmcneal]

Shot some throttle body cleaner around the butterfly, there was some dirt buildup there. Looks like the whole air cleaner assembly needs to come off to really get in there and clean it, though. Ran like crap the first couple minutes after digesting the cleaner, but seems OK now.

Just put a can of Techron in with some fresh gas, we'll see what happens.

you mean cheveron gas?

 

[stevewa]

No the Techron fuel system cleaner. Available in most auto part stores.

Shot some throttle body cleaner around the butterfly, there was some dirt buildup there. Looks like the whole air cleaner assembly needs to come off to really get in there and clean it, though. Ran like crap the first couple minutes after digesting the cleaner, but seems OK now.

Just put a can of Techron in with some fresh gas, we'll see what happens.

you mean cheveron gas?

 

[galaxee]

dealers commonly clean off those throttle bodies for big bucks, sounds like you just saved yourself some money if this does the trick.

how's the car running now?

 

[stevewa]

So far so good. When I get some free time (and better weather) I'll probably pull the throttle body off and give it a thorough cleaning. You do have to be careful with the electronic throttle bodies however as they have integral sensors and servomotors that you can mess up with the wrong cleaners.

dealers commonly clean off those throttle bodies for big bucks, sounds like you just saved yourself some money if this does the trick.

how's the car running now?

 

[tochatihu]

soot

No personal knowledge but I have read that BG 44K induction system cleaners are very good. May even be what Toyota uses. Not that they'd tell me...

DAS