Gen 4 Engine into Gen 3 Prius Partial Guide

1. What are the misfire conditions?

2. What does live data show?

 

Live data shows cylinder 2 and 4bmissfires but very strange when i put in reverse the engine works better.

 

FWIW: in reverse only the electric motors propel the car.

 

Yeah, but engine still work when it's cold to reach operating temperature or when the battery drained to recharge the battery it wont stop the engine completely and misfire still occurs but not as much. Still as i see nobody has any ideas maybe other guys did the swap any sensors or something like that? Maybe i must keep the 4th gen fuel rail? Or maybe i just damaged the wire. no other explanation i can think of now unless i missing something but i didn't saw any post with the same problem.

 

It is not crystal clear what your gen4/3 frankengine is made of. Egr 3rd gen. Head 3rd gen? Intake?

Often diagnostic dead ends occur when someone assumes a potential cause is ok because of a faulty test or no test. Once the root cause has been “checked off” the guy does not return to it and finds himself at a dead end. Recheck everything including electrical, leaks and components.

How did you block the egr flow? My first thought was egr flow at idle and low rpm.

I would also consider pcv and vacuum leaks.

Based on the seller and the cleanliness only?

Do the misfire counters for both cylinders continue to increment all the time? Even at driving speeds over 30 mph/48 kph? If the misfire counter stops at speed it is more likely an egr/pcv/vacuum leak.

Finally misfires changing cylinders on a hybrid can be one plug or coil but the misfires are incorrectly recorded on multiple cylinders. This can be due to engine speed fluctuations caused by a slipping transaxle damper. Very common with a head gasket coolant leak into one cylinder but can happen with an egr stuck open, pcv fault, vacuum leak or one bad plug,coil or injector.

 

I believe i found the problem. I left 3rd gen coils, because i simply couldn't fit the ones wich came with the engine(because of white plastic in picture). So tomorrow or the day after tomorrow i am gonna go and barrow 4th gen coils whitout that plastic and test how car will run. If the problem will stay i can go deeper to rewire everything and etc. I'm doing all this now out of curiosity.

Egr clogging just with simple putty trowel, i test all priuses who have problem with cold start to eliminate egr as a problem you just put putty trowel between egr and egr tube and if the engine won't shake anymore you have to clean/change EGR

 

I've been following skimmilkhybrid on Instagram (https://www.instagram.com/skimmilkhybrid?igshid=YzVkODRmOTdmMw==)

He has done many Gen4 into Gen3 swaps and he says "tuning" after the install is required. He does this with Tech Stream software. Can anyone speak to this?

I'm looking to do the engine swap myself but don't have the skills or knowledge to do tuning. I tried to ask him questions about the tuning and offered to pay him for either the tuning alone or his advice but he stopped responding on Instagram.

 

Well that's interesting tweaking maybe Not sure about tuning they're both two Z Atkinson cycle Toyota open deck engines I'm not sure what will be tuned but yeah maybe that's why he stopped responding because some folks win the questions start getting heavy they get lightheaded or something but usually not when you're throwing money at them so that's interesting but I mean think about it The generation 4 is just got some sleeves and some various band-aids applied . So I don't think tuning will really be at play here there's some different hose routings and things like that that come into play but my goodness that's a one time affair not really tuning per se.

 

He is blowing smoke about tuning with Techstream. The real issue is getting different sensors and hoses to marry up. You have to run gen3 computers and networks. To that end, most use a lot of gen3 parts and pieces on a gen4 engine.

 

That link doesn't even load.

 

He is Drew Griffin and has posted here before about an Oklahoma based gen4 to gen3 mobile service. Recently he said too many problems were occurring after he traveled long distances and too many call backs. So he said no more mobile services but he might do jobs at his place in Oklahoma.

 

I feel that. Engine swapping even G3-G3 is not an exact science and nothing is equal in all cars. There are so many factors to get the swap running 100% smooth in all cars. A lot of liability with random check engine codes or new sounds that weren't there before. Customers need to understand this before going into it.

 

If I had a blown head gasket and likely knackered block, I'd be much more inclined to transfer my existing head to a brand-new (gen 3) short block, check/clean all, and reassemble with the Toyota gasket kit and new head bolts.

 

If you had money for the short block, it might be also wise to take your head to a machine shop who does heads and have them "clean it up" a bit and replace the valve seals...

 

No tuning required. They are blowing smoke. The Gen 4 engine acts and responds to the Gen 3 ECU commands as if it was installed there by Toyota.

 

Yes of course it does It's the same engine because you've added some sleeves and some dividers and a different set of rings I'm still the same engine bore stroke engine family running and duty cycle same That's why these things work and these kinds of swaps work because you're really changing nothing some underwear under the suit if you will.

 

There seems to be an overheating issue though. Maybe the coolant re-routing is a factor? Or are there 4th gen temp sensors swapped over, and they don't work well with the gen 3 computer programming?

 

Coolant temp sensor wire extension is about it, and the slightly different single coolant outlet hose from the head. I don't have any cooling issues at all on mine, in fact it runs cooler than normal most times. Ever thought about the Gen 3 head option on a G4 block to eliminate the modifications?

 

That's what @cnc97 did; he's the pioneer, likely the first person on earth to do such a transplant. Soon after @Ragingfit chimed in, and provided a video saga of his second transplant: first was a gen 3 hatchback (IIRC), and then he did his Prius v.

They're akin to Scott Carpenter and John Glenn respectively.

 

With all do respect to them, there was a shop in Southern California that was doing it much before them likely...