Engine runs, then stalls P3191 code, oil in the intake manifold?!

The way a Prius starts can fool you if you haven't worked on it before. The electric motor that starts it is something like 13 HP, so instead of sounding like a regular car's 12 volt starter struggling to crank, it just spins the engine up to 1200 rpm right away (which to most people sounds like "the engine starts"). The computer doesn't start sending fuel and spark until some seconds later, and that's when the engine has to really take over the work.

So the description you've given is really the classic one for "engine just doesn't start." And all the classic next steps apply: Compression. Fuel. Spark. Which one is absent?

A small amount of oil in the manifold is not unusual with the Atkinson-style valve timing.

-Chap

p.s. Don't forget that every starting attempt you make will use some charge from the HV battery, which won't get recharged until you solve the problem and get the engine to start. If it gets too low, an HV battery charger is not something you'll find at the corner parts store. So ... make this a "think" project, and budget your starting attempts so that each one is going to tell you something you need to know.

 

your oil was overfilled at some point... or slightly at multiple times. the oil finally built up to cause a vacuum loss in your intake therefore stalling.

i recently had this happen on my genII. in January i took my car to jiffylube to change the oil. i was sick so i didn't want to do it myself for once. they overfilled and me not feeling well, i didn't check it like i normally do. a few days later it took it's toll and the engine no longer worked.

in the end the repair shop cleaned the body and all attaching lines. jiffylube paid for it all...

 

At 77k miles and 10 years, you might have the spark plugs checked. Also make sure there is no 'crap' in the spark plug access holes. It is very easy to have water and/or oil get in the holes. I believe there was a TIS about this for the NHW20s.

Don't rule out 'critters' as some rodents think Prius wiring tastes great.

Still the best attitude is to treat this as an ordinary engine starting problem. Don't forget to check the fuel pressure.

Bob Wilson

 

I bet the dealer would say $1200 dollars to replace throttle body... And if that didn't solve it they'd start charging even more to replace other stuff. Hopefully for you that's not the problem though...

 

How about letting us know your home town? There may be independent shops that could lend a technical hand.

Bob Wilson

 

Great - if you're mechanically inclined, you'll find the Prius service manuals a huge help. There are two volumes, each the size of a major-city phone book, the first is all diagnostic procedures, the second is access, disassembly, and reassembly. The electrical wiring diagram manual is a separate small book and shows you every system in the car called out separately, plus a combined diagram of everything in the back of the book, along with locations and identification of every connector. There is also a New Car Features Manual, a smaller book that explains the why and principles of operation of all the things mentioned in the other manuals.

If you like printed copies, they're now distributed by helminc.com; the online copies are on techinfo.toyota.com where a two-day subscription is something like $15. As you have an issue to solve right now, you might be impatient for shipping of paper copies so techinfo might be the way to go.

Checking compression on a Prius can be tricky. There's actually a command to the computer to crank the engine at 250 rpm so you can take a reading, but you need a very Prius-specific scantool to send that command. I picked up an OTC 5609 leakdown tester, which costs less than Prius-specific scantools, and lets you test compression without cranking if you have a compressed air source.

Are you aware of any recent work being done on or around the engine?

-Chap

 

isn't starting a new thread for the can of worms you already opened a little repetitive?

did you actually ever mop up the oil from the bottom of the intake manifold? take strips of a clean rag (no loose fibers) and mop up the oil. if you want to go into more depth, you can also clean the emission lines. (from the pcv, and so forth)... careful since there is water that passes through the throttle body too. you don't want air to get in those. if you take it to a mechanic and they find the oil was overfilled or a buildup over time lead to a similar problem, they will drop pieces of rags in there and mop it up and most likely the car will start up afterwards (that's basically what they did to my car)

i simply think you could be jumping in the wrong direction. the first question should have been "how's your oil level?"... anything over full is too much.

when i played with my car over and over, pulling fuses and relays, i could get it to run rough and then shut off again with error codes. i wanted to pull the entire intake off and clean it but i didn't have the socket set since my buddy borrowed it and "misplaced" it...

 

also check for spark at those spark coils on top of the plugs, one of those could be misfiring too. plugs first then try the coils

 

Can't imagine how you'd check for a spark directly on the coils... How's that done? I've read on here about switching the igniters to see if the problem of a cylinder not firing moves when the coil moves to a different location, but that's about it.

 

If I wanted to check an igniter, I would remove the igniter, attach the wiring harness connector to the igniter, insert a known good spark plug into the igniter, ground the threaded shell of the plug, then have a helper try to start the Prius while looking at the spark plug tip for sparking.

 

same here, unless you have a multimeter that allows you to clamp around the wires to pick up a signal. thats how i would do it.