5.7 swap now no fire.

So I have a 2010 sr5 crew cab 4X4 with 5.7. High miles 500,000 I also had a 2017 with 5.7 low miles it recently got rear ended and I desided to swap the low miles motor into the 2010. After swapping motor and transmission kept the old transfer case be asue the plugs were different. Wire harness off my 2010 plugged right up. Everything seemed the same. But I can't get fire. I've been over this thing for several days can't find the issue. Crank sensor I couldn't get to test so I replaced that I refuse to randomly throw parts guessing. Any help would be greatly appreciated. As I am out of ideas.

 

Likely a harness incompatibility issue. The 2010 and 2017 are essentially two different generations of truck.

 

In general the trucks are the same but Toyota moved a lot of wires to different locations in plug between them.

Have you plugged in an OBD reader and look for trouble codes?

Did you use all the sensors, coils, injectors, MAF ect from the 2010 engine? You essentially want a 2017 engine running with the 2010 harness and sensors.

The physical engine block ect is the same however sensor plugins and communication are most likely different due to a newer style harness in the 2014+ trucks.

The only way to know for sure what is the same or different between the two is compare 2010 and 2017 wiring diagrams for each connector. I had to do this when I swapped a 2014+ dash/interior into my 2007 truck. Almost all the plugs were the same size but wire pin positions were different

 

so yes as you all have mentioned the electronics would be the issue as the motor mechanically was the same. as I had said or tried to relay I used my original wire harness and made sure to change any and all sensors that were different. most everything seemed to be the same on the sensor side. the plugs on my orginal 2010 wire harness all fit and plugged up just like factory there were only 2 sensors that my 2010 had that my 2017 didn't and of course I used my orginal sensors. I have since figured out the problem and felt a little like "" damn"" when I found it.. just t0 pass on my problem. after spending a long time checking and rechecking every plug and sensor on the motor and transmission and even transfer case there were no codes. motor would crank had fuel but not fire at spark plug. I was feeling defeated and was just about to give up take it to dealer. when I was cleaning up my tools and collecting all my testing gear. I noticed that the plug on the ecm wasn't bottomed out. were talking just a millimeter or so. but none the less it wasn't bottomed out. so as I investigated I found the lever that locked the plug into the ecm was cracked small but it left the plug ever so slightly off bottom. so I removed the cracked lever that was keeping it from bottoming out and pressed it in firmly. again I only got another millimeter or so out of it. but that was it.. happy dance about 3am when I discovered all this. pure joy. honestly the plug was plugged in by all accounts and lever had locked. it was just pure happenstance that I noticed this very small thing the connecting pins are very small and that last little tiny bit of wiggle made the difference... shes running like a champ now.

 

Great job man.

 

Been here before and it’s a great feeling to finally solve a problem that looms this long. Congrats.

I guess it was pulled in just far enough to not throw a trouble code. Odd but weird things happen.