I replaced the 3.4 in my T100 4x4 with a JDM motor. It started right up, ran great but after 20 mins. of starting it up turning it off and checking it out it stalled and won't restart, cranks over real good just won't start. A hand held scanner can't connect and the CEL stays on even after I pull the key out. Any ideas?

 

I'm assuming you used the existing computer from the truck? Did you compare all the sensors between the original motor and Jdm? I'd try pulling the efi fuse for 15-30 seconds and see if resetting the computer fixes it.

 

I only switch the oil pressure sender because when it first started the oil pressure gauge didn't work, put the old one in and it did. The "new" motor is newer so I left the cam and crank sensors on. I did pull the fuse to reset it. I put a new ignition switch on thinking that might be it, no help. Everything is the stock stuff. Can a good repair shop's analyzer isolate a problem like this because I'm not above letting someone finish this job for me. Nuts and bolts I can twist and this was a big job for me, I did a nice job but I'm over my head now.

 

Did you use yer original harness or the new motor's harness?

 

I used the original harness, throttle body, and plenum. The Toyota dealer in my town isn't very good but there's another 10mis. away that I'll go to next week and see if they can diagnosis for me. I don't think this is related to the new motor so much. I think this is more of a coincidence and its unrelated. It just ran to good when it started. I'm tired of racking my brain and I just want it fixed. I'm a weekend shift worker so I can't do anything till Monday now anyway.

 

How much newer are we talking? In the run of the 5VZ there were changes to all different parts of the motor. Try swapping the cam and crank sensors from your original engine. I can't think of any changes between years in these areas but you never know.

 

Op, I just ran your issue past our shop foreman. He said double check all your wiring to make sure power isn't being fed in where it shouldn't be. The only reason the check engine light is staying on when you remove the key is because something is always powering the computer. Also, double check the efi relay, to make sure it's not sticking. The efi relay supplies power to the ECM and all the engine sensors.

 

The new motor had the oil dip stick in the front, I had to move it to the side. I read somewhere that made it a 2000 or newer. I pulled that efi relay and I can see a difference in the size of the spark between the clamp and the post, it seemed smaller. The cel is off now. I'll take the relay in to work tomorrow and have one of the CNC lathe techs check it out. I feel your pointing me in the right direction. I'll post the test results tomorrow. Thanks

 

Ok 250000 yotaman, You sent me to the right side of the motor. I reached up from the relay box and found that I hadn't tighten the three ground wires at the front of the intake plenum. tightened them and it started right up! I wanna thank you and BamZipPow for keeping me on the right path to repair. I'm happy now. Thanks again

 

Knew it had to be something simple.