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Brad, Jeep Dealership Tech
Category: Jeep
Satisfied Customers: 8063
Experience:  19 Yrs Chrysler/Dodge/Jeep. ASE Master (L-1) Certified
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I have a 2002 jeep liberty that i did an engine swap this

Customer Question

I have a 2002 jeep liberty that i did an engine swap this weekend, to a 2005 motor. both motors 3.7 liter. Old engine had timing chain failure issues. I put on old intake manifold, with the 02 MAP sensor, IAT Sensor, IAC sensor, only change the throttle position sensor to the 05 due to breaking the 02 when i disconnected it. Oil pressure sensor was changed to 02 as it was a different connnector and number of wires. 05 Camshaft and Crankshaft position sensors were left on new motor. Motor will not run, acts like it is out of time. I swapped to the 02 crank and cam position sensors and it acts the same.
Submitted: 1 year ago.
Category: Jeep
Customer: replied 1 year ago.
The only sensors that remain from the 2005 engine are the knock sensors. are they different from an 02, to and 05? would they affect timing?
Expert:  Brad replied 1 year ago.

Good morning and welcome to JustAnswer!!!

Can you tell me if the 2002 had a 3 connector PCM and if the 2005 had a 4 connector PCM? If so then your issues are that they are different engines.. The 2002 is a JTEC engine and the 2005 is a NGC engine..

Customer: replied 1 year ago.
PCM is the computer ? I did not see the other vehicle.....only the engine. all the engine sensor connnectors fit except the oil pressure sensor......
Expert:  Brad replied 1 year ago.

The 2002 is a JTEC(JeepTruckEngineController) and the 2005 is a NGC(NextGenerationController) which means they may look the same from the outside but internally they are different engines.. The only way you could possibly get this running is to swap the tone wheels from the 2002 to the 2005 engine and I mean the crankshaft and the camshaft...

But here at the dealership we would suggest replacing it with the correct engine..

I hope this helps,


Customer: replied 1 year ago.
Unfortunately yes this helps......wasnt answer I was hoping for.... Can yo tell me is there a way to tell the 2 engines apart when they are out of the If i bring one home again it would be for sure the JTEC engine ?
Expert:  Brad replied 1 year ago.

The easiest way to tell the difference is to check the PCM and see if it has 3 connectors which is a JTEC.. I get customers that run into this weekly and some pull the engine and swap tone wheels and some get the right engine. Both will plug and and everything will fit perfect but on the inside they are different engines..

Glad I could help,


Expert:  Brad replied 1 year ago.

Thank you for the positive rating so I'm compensated for my time.

Have a great day,


Expert:  Brad replied 1 year ago.

Since I haven't got a reply I'm guessing you have it fixed....

Glad I could help and thank you for the positive rating,