I think I'm going to sell...

If it's throwing codes it's not inspect-able, so it's going to be sold as metal or salvage....
My 2ng gen is very particular about exactly what spark plug it has, 10mpg particular, just sayin..

 

I'm not a mechanic but maybe the helps. The table from a corolla, may not be universal for Prius

OBD-II Trouble Codes: Full List! - Toyota Nation Forum : Toyota Car and Truck Forums

 

I think it is something around the gas tank. Wait for one of the Master a mechanics to respond to the thread. Patrick Wong or Avi are very good.

 

Requested post be moved by moderator to Gen 1 discussion, plus link to prior posting...
Generation 1 engine problem | PriusChat

 

This is the full list of suspect areas with DTC P0171 which means you have a lean air/fuel mixture:

Air induction system
Injector blockage
Mass air flow meter
Engine coolant temperature sensor
Fuel pressure
Gas leakage in exhaust system
Open or short in oxygen sensor (bank 1, sensor 1) circuit
Oxygen sensor (bank 1, sensor 1)
Oxygen sensor heater (bank 1, sensor 1)
Circuit opening relay
PCV valve and hose
PCV hose connection
ECM

You've addressed many of these areas already. Since the problem is intermittent I would look for a loose wiring harness connector. You may need to seek professional assistance to further narrow down the problem.

 

P0171 is a lean condition. Find a shop with a smoke machine and have them smoke test the intake.
It will test the breather system, the PCV system, the intake and all the related vacuum hoses.
Always make sure the brake booster isn't leaking also. Most will leak and cause a stiff pedal.

Here's some diagnostic data for things to look at.

 

May I ask where you are located?

 

Prius does not have a brake booster activated by engine vacuum. This is because the engine frequently is turned off during the course of normal operation and obviously there would be no vacuum available during those periods.

Instead Prius has a brake actuator that contains an electrically operated pump to develop pressure in the hydraulic system. This pump can usually be heard running for a brief period after the driver's door is opened, prior to the car being made READY. It also will be heard running from time to time while the car is READY.

 

Sorry to hear about your problems. Can you tell us where you are located? We know of many credible, independent Prius mechanics who might be able to help diagnose what is going on.

What type of scanner are you using? The standard, over-the-counter scanners are not 'Prius-aware' and do not read out Prius specific error codes. There may be something else going on that a 'Prius-aware' scanner, something an independent Prius mechanic would have, could give more insights.

* * * astrolink * * *
. . . Runs very rough at times at idle upon startup, codes p0171 and misfire codes. . . . mileage is at least 10 less then it should be. - Sounds like it may be running in "open loop." What are the long term and short term fuel trim doing?

With no change to symptoms, I've changed:

1) Spark Plugs - A Prius-aware scanner, if I remember correctly, would identify cylinder.
2) Coils - ""
3) Upstream O2 sensor - What is the voltage swing? How soon does it start?
4) Temp Sensor - What is the temperature profile over time?
5) Mass Air Flow Sensor (twice; once with a cheap Chinese one and again with Denso) - What sort of gm/sec are you seeing? Does it change as the coolant temperature increases?
6) Throttle body and gasket - Throttle body is usually pretty expensive, used part?
7) Intake gasket - The intake manifold was removed?
8) PCV changed - Reasonable, what did the old one look like?
9) Inspected vacuum control on exhaust; working fine. - Good
10) cleaned intake of oil and made sure it's not overfilled - Good
11) 2 bottles of fuel injector cleaner - Should have done the job but if you took the manifold, were the injectors removed? One of our members had a problem with the injector gasket.
12) Checked for vacuum leaks - Method? Some are better than others.
13) Cleaned around gas cap to make sure there is a good seal. - Good
* * *

Bob Wilson

 

I can not emphasize enough how important it is to have a 'benchmark.' Ideally, do it when you first buy a car and then save it somewhere. If there is any question in the future, re-run the 'benchmark' and you'll know.

WELL DONE!
Bob Wilson

 

Thanks for the update - it appears that the second item from my list in post #7 above was your car's problem.

Please comment on how difficult or easy it was to replace the injectors.

 

Did you just leave the third bolt in place then and find the fuel pipe flexible enough to lift and get the injectors out? Out of all three, that's the one that's a PITA to reach (down on the end of the head roughly under the PCV valve) but I was chicken to try leaving it tight and bending the rail around. That would have saved me some time.

Hmm, I wonder if that's why they built that goofy hook of the valve cover that lies over the fuel pipe. Maybe they figured out how far you could safely bend the tube without fussing with the bolt in the back, and then added the hook to prevent going too far. Pretty clever if that's the explanation. Even more clever if the guys who figured that out could have mentioned it to the guys writing the manual....

-Chap

 

Also, do you still have the old injectors, or did they go back as cores? I'd be curious to get a test report on them (from somebody like Cruzin Performance) just to get an idea what the numbers are when lean-running symptoms and codes appear.

-Chap

 

Well, I'm glad this problem is finally fixed!!!!!