Still Misfiring After Cleaning IM - Please read

And maybe a compression test so you know which cylinder is most worth scoping: Compression Test | PriusChat

 

Sure wish we could better understand why in the heck ruined Prius longevity by redesigning the EGR system and blowing up the engines early? How come Gen2 Prius never have this problem?

 

If you can document the repair work and share it, that would help others in this situation....

 

Second gen doesn't have EGR?

 

It's an interesting question in that the Exhaust Gas Recirculation (EGR) is way different on a Gen2 Prius compared to a Gen3... And if you do some googling it seems as though parts for Gen2 EGR system are hard to find, barely even exist, but there's a flood of them for this major defect in Gen3.

Thinking I need to do a new post about this to get more info... There's a solenoid in Gen2 EGR valve system and the pipe seems to have more capacity. Also the Gen3 EGR Valve assembly has a cooling system with a smaller pipe. But I've not worked on 'em so I'm just Googling, which too often gives you the most popular answer not the right answer.

Perhaps the addition of the cooling system design is what ultimately led to destroying Gen3 engines prematurely?

 

Just found that @Tideland Prius mentions in this 2009 post about differences between Gen2 and Gen 3:

"Exhaust Gas Recirculation System (recycles cooled exhaust to lower the engine temperature. It saves fuel because normally, fuel would be used to cool the cylinders)" Differences between Gen II and Gen III??? | PriusChat

So now that the Gen3 are getting closer to a decade on the road, it seems that this "improvement" was an epic fail in terms of engine lifespan, unless you add an oil catch can and do regular cleaning.

I wonder if Gen4 and later model Gen3 made changes to solve this problem?

 

Gen 3 EGR remained unchanged through 2015. I put a 2015 valve and cooler on my 2010, and they were identical to the naked eye. Gen 4 moved the EGR cooler downstream of the cat, presumably to try and further clean up exhaust gas before it enters the EGR path. It's still external, cooled EGR from the same playbook as turg gen, tho. Time will tell, but I'm betting (hoping) it will prove to at least be an improvement.

 

Pretty sure origins of EGR were related to strict California vehicle emissions requirements that got us out of the smog alert days of the 70's and early 80's. As far as I know EGR has been a standard emission requirement on all gasoline vehicles for a long time, and not just in California. If I'm incorrect I hope someone says something!

 

My '07 Mazdaspeed 6 has an egr. It had a tendency to clog and throw a CEL. We just block it off and delete it.

 

The first car I had with an EGR valve was my 1977 Cougar XR7. The first car I remember with a catalytic converter was a Chrysler about 1975 and they used what was called the "Lean Burn" but those were carbureted cars.

 

Gen 2 EGR parts really don't exist. The ecu controls VVT to allow back flow of exhaust gas into the intake at typical EGR indicated engine loads. Slick and maintenance free but the cooled, external set-up (gen 3 and 4) allows for higher thermal efficiency in the hunt for higher mpg's.

VVT solenoid?.. And what "pipe" are you referring to?

 

I don't think second gen has EGR. The term Exhaust Gas Recirculation does appear in the Repair Manual acronym list, opposite EGR, but that's the only place it appears. Looking at the exhaust manifold and exhaust pics, there doesn't appear to be anything branching off:

 

Thanks for helping us understand @Mendel Leisk and @m.wynn

I was simply using Google image search and Ebay search, as well as looking at old articles online to figure it out and the pipe and solenoid were descriptions on Ebay when searching for EGR stuff for Gen2 Prius, which may not be that accurate...

When you're saying VVT you mean Variable Valve Timing, right? So essentially it's recirculating exhaust gas by keeping the exhaust valves slightly open on the intake stroke. That's pretty clever... A great way to simplify the system...

 

Im pretty sure VVT was meant to improve performance and Honda comes to mind. A lot of performance seems to trickle down from racing.

 

Wikipedia lists the 1nz-fxe as having VVT-i. That's one VVT on the intake side. Wouldn't you need a dual VVT-i for EGR?