Gen 3 to 4 engine swap failure

Ok did the swap and everything seemed so promising but then it just doesn’t stay running. Scan cam back with cam sensor, temp, maf, knock, and water pump with a check hybrid that won’t go away no matter what I do. I checked the timing was right, ground was good-I disconnected it and nothing would work - i reused my old sensors thinking maybe the ecu was more accustomed to them still nothing. I recharged the hybrid battery which took longer than my gen 2 batt and wouldn’t Charge as high but would turn over the engine. It charged to 59.6 SOC According to techstream . I Check every fuse, held the pos and neg terminals together to zero out the man ecu still nothing. Ran techstream on it and it wouldn’t connect with the cars ecu but did come back with two codes for cam sensor and maf sensor. Which it seems my Walmart OBD2 reader was better came back 5 codes. Checked the wiring harness nothing there no rips no Tares. So I’m currently wandering if its the ecu because I read a form here were a guy did a regular gen3 swap And his car wouldn’t start and he had to have the ECU flashed before it would run. So I’m thinking head to the junkyard grab another ECU out of a newer car maybe a 2012 and see if it works. Any ideas please help and thanks

 

No I just mean that putting everything together seem to go I like clockwork and the engine did spin up for eight or 10 seconds then stops. Well the cam sensor that came with the engine was like brand new and I never had an issue out of the maf sensor before so I can’t understand why I would have one with it now it makes zero sense. But I can try it at this point I just feel like I’m just throwing money at everything again, tired of doing that already

 

I remove the valve cover and the spark plug so the engine could just turn over with that resistance and I turned it over and it has a special chain links on it that are colored orange and there’s a Nick in the balancer that shows when it gets to top dead center and all that was a line perfectly the engine is in really good condition only had like 60 something thousand miles on it so I don’t understand I’m thinking it’s probably the ECU but I don’t know since I have all those codes that are coming up it could be something in the wire harness now that’s causing more voltage because all those sensors are on the same side of the wire harness so .

 

I have noticed that the engine is firing because the exhaust was hot. Also I do smell gas. What I’ve been doing is pulling the white main wire to reset the computer and trying to get it to finally continue running. I guess I’m thinking it will eventually self regulate. I did order a new cam and maf sensor . I’m going to call a dealer to see if I can have the ecu reprogrammed So I can just remove it and take it to them. Also considering ordering another wire harness. Just throwing money at hoping.

 

Gen 4 in gen 3 body used the gen 3 intake & exhaust, gen 4 water pump. Kept originals sensors cam , temp, knock etc and ecu,s.

 

Yes I watched all of fix that Prius‘s videos and many many others before I decided to do it and there was never an issue with the problems that I’m having whatsoever I currently think that it’s probably the computer in the car that needs to be updated somehow but looks like what I’m gonna do is I’m just gonna rebuild my old engine then have the computer updated and try the engine swap again Later.

 

I just don’t have the time to wait I have a head coming back and I have a set of new piston rings I think I’m just gonna rebuild my engine and throw it back in there and then possibly take the car and have the the computer updated and then at some later time try again and see what happens.

 

You know it finally started running. I just kept resetting it and the it started running on its own. It sounded like a war zone at first but little by little it smoothed out. Now it has a misfire in cylinder 4 and the gen 4 water pump needs replaced but cam sensor code and the check hybrid message is gone. Its a pretty smooth and quiet engine. I’m a little freaked though after having this much difficulty I’m wondering how road worthy it will be in the future. Now just glad it’s running .

 

Hey that sounds like what just happened with mine. I kept resetting it and it finally started running. Sounded like garbage but then quieted down. Now it has a misfire in #4 and needs a new water pump. Not sure about the misfire. I used the gen 4 coils and put all new spark plugs in before starting it up.