2007 Prius - Misfire Cylinder 1

Well, it was super easy in my gen 1 without a scan tool, just pull the CIR OPN relay out of the front fuse box and stick a jumper between the two wide slots in the relay socket.

Not as easy in gen 2 because the C/OPN relay is one of the four relays combined into "Unit C" in the fuse box (which has a big letter B on it, and should not be confused with Unit B, which has a big letter C). Anyway it's the one with four blank fillers on the top instead of four fuses. Would have to lift that item out of there and bring 12 volts to the red wire 3G pin 8.

Or just plug in a scan tool with active-test capability, put the car IG-ON (but not READY), and tell the scan tool to please turn the fuel pump on.

Maybe some would prefer to pop the back seat and bring 12 volts right to the pump. In gen 1 that was more trouble than popping the relay out.

I see in gen 3 it's about the same deal as gen 2; the C/OPN relay is one of a four-fer module in the front fuse box. Bring 12 volts to the red wire 1B pin 8. (Or just tell a scan tool to please turn the pump on.)

 

That B00061 illustration is really terrible at conveying information.

After staring at it for several minutes it seems to be trying to say "don't let the O-ring shift out of its groove during installation" (assuming there is a groove - not clear in the picture), with the bottom two being somehow different ways the O-ring can move incorrectly. The thing is, there would be no way to see the O-ring's position, good or bad, because once the injector is in the installer's view of it is completely blocked by the injector and the pipe. So what's to be gained from the illustration?

The written installation notes that say that the injector should be able to rotate smoothly are better. That at least gives the installer some useful information about what it should feel like when it is correctly installed, since what it looks like won't be very helpful. As a corollary, if three of the injectors all spin the same, and one doesn't, that would be a pretty good clue to pull that one out and try again.

 

Insight. They show you the secret view of what you can't see, so that when you see other parts of the instructions, like "twist after installing and check that it turns freely", you go "ah yeah, I get what they're wanting me to check!".

 

Having a good bidirectional scanner beats yanking on wires every time.

Regardless "all is well that ends well" which begs the question - did injectors fix it?

 

Select the engine system, find the Active tests menu. In the drop-down list, select the desired test.

Fuel Test by MAX2 posted Apr 15, 2025 at 9:23 AM

Cleaning an old injector for 25 is not rational. It is better to buy a new one.

 

I would not spend the money trying to repair injectors you will never need again. I might keep them especially if you know which three were good.

 

Around the 25 dollar price point, your only choices are going to be quality injectors that have been restored, or new really cheap ones.

About $19 per injector was what I was paying a dozen years ago* when we had PriusChat circulating restored injectors. When we started, there weren't as many sellers offering restored sets to purchase.

One thing I still liked about getting the originals restored was getting the before/after test results back. Those could be reviewed against how the engine was acting before, and help to either confirm that the injector restoration has solved the problem, or to keep aware that there may still be some other issue.

I'm not sure what documentation you get when buying a set of purportedly restored injectors.

I would still probably prefer a restored actual Denso to a new knockoff or counterfeit at the same price point.

If you don't have any use for the old ones, perhaps it would be worth contacting one of the businesses that offer restored sets for sale to see if they want them.


* so it's gone up around 25% in a dozen years, or an inflation rate around 1.88%—lower than most other prices over the time period.

 

MAFS and MAPS are two different things.

MAFS is a mass airflow sensor.
MAPS is a manifold absolute pressure sensor.

The Gen 2 does not have a MAPS.

 

That really shouldn't be a thing. The rail spacers should be in place under the rail and those bolts, so even if you overtighten, you might risk breaking the bolts but it won't change how the rail sits.

If O rings got mangled they probably weren't in the rail right to begin with ... illustrations back in post #14.