Replaced Engine--Now it won't Idle

[Starrada]

I have a 2008 Nytro RTX, the engine went bad so I replaced the engine with one out of a 2009 Nytro. The engine is in and will start up fine, as soon as the temperature light goes out the idle drops and the engine dies. The engine will run if the throttle is held slightly open. I have found the throttle play to be 3-4mm as the manual says and I have checked the throttle position sensor diagnostic; it read 16% at no throttle and 95% at wide open throttle. What could the issue be?

 

[maim]

08 cdi or 09 cdi? might need to put all your sensors from the 08 on the 09 engine for it to run right. seen that on some big truck engines.

 

[aproudcanadian]

Does it only do this cold or even after it’s warmed up?

 

[Starrada]

Does it only do this cold or even after it’s warmed up?

It does it even after it has been warmed up

 

[grizztracks]

Was this engine purchased with an unknown history? Did it come with it's original throttle body? You might want to pull the valve cover and check cam timing to make sure it didn't jump a tooth. With the engine swap it's possible the new engine was rotated backwards which can cause it to jump time. Also there have been a few reports of slipped reluctor rings on the stub shaft which will cause poor idle. I don't believe there were any changes from 08 to 09 that would make me believe it's ECU related.