Fuel injectors gone bad, or so they say!

I believe that there is benefit to be gained from sustained usage of a Top Tier gasoline brand (Chevron happens to be one of those.)
Top Tier Gasoline

MSRP of the Prius fuel injector is $163 and you can buy them for $124 each, plus shipping here:
Champion ToyotaWorld

It is not that hard to replace the fuel injectors. Depressurize the fuel rail. Remove the cowl that runs over the engine for access to the engine valve cover. Then remove the engine wiring harness over the valve cover by disconnecting all wiring harness connectors to the igniters and injectors and unbolting the bolts that hold the harness to the valve cover.

Remove the valve cover to gain access to the fuel rail, then remove the fuel rail. At this point the injectors can be removed and replaced with new. Good luck.

 

1. I suggest that you subscribe to techinfo.toyota.com so that you can obtain repair manual pages that relate to this repair.

2. If you had a Classic, it would be very easy to depressurize the fuel rail as you would just unplug the Circuit Opening relay while the Prius was READY, which would turn off the fuel pump and cut off the fuel supply. Hence, the engine would consume the remaining fuel in the fuel line until the pressure had dropped to the point where the injectors no longer would inject, then the engine would stall.

3. However, 2G has a fancy relay module that contains multiple relays including the Circuit Opening relay. The repair manual suggests removing the rear seat cushion, then disconnecting the fuel pump wiring harness. Then make the Prius READY and let the engine run until it stalls. As an alternative, you would need to find the fuse providing power to the fuel pump and pull it. <I don't have access to the wiring diagram at this moment, so you'll have to look that up as well when you subscribe to techinfo.>

4. The fuel rail is automatically pressurized the next time you make the Prius READY, as the fuel pump will establish a minimum pressure of 44-50 psi.

 

If all three codes came on about the same time, your stealership is trying to do a walletectomy on you. His inflated injector price is another clue.

Those codes are semi universal codes for cylinders misfiring, injectors don't suddenly die in multiple cylinders at the same time.

I believe (but check) the codes mean

P0300 multiple cylinder misfire
P0303 Cyl 3 misfire
P0304 Cyl 4 misfire.
http://www.ricksfreeautorepairadvic...305-p0306-p0307-p0308-p0309-p0310-p0311-p0312

More likely you have a fuel pump, emissions system or ignition system problem. Someone here should be able to tell you if the diagnostic system will throw a code for fuel pressure, if it will, then your fuel pressure is probably OK because you didn't get a code for that. I think you would get

Code:

[LIST]
[*]P0087 Fuel Rail/System Pressure - Too Low
[*]0r
[*]P0088 Fuel Rail/System Pressure - Too High
[/LIST]

if your pressure were seriously off either way

It sounds more like an ignition or emissions controls problem. Is there anything in the ignition system that could cause 3 and 4 to start misfiring at the same time.

A good share of trouble codes are generic. Plug them into Google and you will get clues.

 

hobbit has a description on a cutoff for the fuel pump ; 04-09

http://www.techno-fandom.org/~hobbit/cars/nosquirt/

inserting a cutoff switch in the lead to the electric fuel pump is even simpler. This describes a surprisingly easy method and location to install one in the '04 - '09 2nd-generation car.

and
There is no dedicated fuel-pump fuse, unlike that found in many other cars; the pump simply feeds off the 15A AM2 supply.

Also about the question -I had a CEL come on over the weekend-, If the engine runs okay other than startup , I would try running some good injector cleaner again, perhaps your current tank of gas is the problem.

 

Is it always rough at startup? How many times has the CEL come on? Every time after clearing the code?

It just seems awfully strange. There's an ancient TSB for 04-05, basically water comes through the cowl and causes one or more cylinders to misfire and perhaps damages the ignition coil. Actually, Patrick Wong posted it a few years ago: http://priuschat.com/forums/gen-ii-...g/45550-ignition-coil-getting-burned-out.html Also possible that the wiper tray drain is plugged and is also causing excess water to enter the engine compartment. Anyways, I'm suspicious of you needing new injectors. I've run 150,000 miles at 25 mpg in a 2004 RAV4 (same injectors as your Prius) using only the cheapest gas and have had zero fuel/ignition problems. If in doubt, pull the injectors and mail them off to be ultrasonically cleaned and flow tested.

 

Don't worry about the oil "sheen" at the bottom of the throttle body. That is normal.

Occasional use of fuel injector cleaner is OK, but you should not overdo that either. It wouldn't hurt for you to buy top tier fuel for a while.

You might want to remove and inspect the spark plug igniters for cyls 3 and 4 (the two that are closest to the inverter) to assure yourself that they are in good physical condition (no cracking or burn marks on the plastic body.) Look for rust stains which would show that water had entered the spark plug well. If there are any problems, replace the igniters and that will probably take care of the misfire DTC. Good luck.

 

The goodnews/badnews is that you learned something about your dealer.

 

It is possible to damage the MAF sensor while cleaning the throttle plate, and that could cause such weirdness. I don't know how to test for that specifically.

If you have trouble again, if at all possible take it to a different dealer.

 

I agree, do not pay the Stealer for this! It could simply be a bad tank of fuel. Continue driving normally and see if you get another code set after a fresh tank (and different brand) of fuel.

As Patrick said, Oil in the Intake is a normal artifact of the PCV system, it will not hurt anything.

Be careful using cleaning fluids on parts like the Throttle body. I recommend you take the TB off while cleaning so excess fluid doesn't enter the engine. I've seen things like this destroy oxygen sensors and catalyst systems.

 

1. Yes, the MAF sensor needs to be cleaned now. You can buy the correct cleaner at discount auto parts stores.

2. If the CEL comes back on, I would suggest replacing the fuel injectors for cyls 3 and 4 since those were the cyls with the misfire.

 

Ding ding ding ding ding! We have a winner. Clean it correctly and your problem will most likely be over. See Patrick Wong's recent excellent post on the subject:
http://priuschat.com/forums/gen-ii-...-airflow-sensor-instructions.html#post1218678