How to Tell the Difference between 4.7L JTEC and NGC engines
Dodge Jeep 4.7L
Starting in mid 2002, the Dodge 4.7 engines switched from a 3-Connector JTEC Power Control Module (PCM) to a 4-Connector NGC PCM. Module may also be called an ECU or ECM.
They are Not interchangeable.
Changes were mechanical, electronic, and component, affecting the Crank Reluctor Wheel Tone Ring, Computer, and Timing Cam Gears.
Checking your VIN number will not tell you which you have, you must make a visual inspection. We need to verify this to provide you the correct replacement engine.
How to Tell the Difference
- Check your PCM under the hood.
- Inspect your Crank Wheel Tone Ring.
- Verify the Windows on Cam Target Wheel.
- Compare to photo examples below.
Does PCM have 3 or 4 Connectors?
Once you locate the PCM, count the connectors. 3 is a JTEC, 4 is an NGC controller.
Count Teeth on Crank Tone Ring
JTEC is a 16 Tooth Ring. NGC is a 32 Tooth Ring.
Looking at the Cam Target Wheel
View Right Head Cam Target Wheel. Look near the timing mark for the little “Windows”.
Check PCM First
First, you should check under the hood by the fender or at the firewall. Find the Power Control Module (PCM) and count how many connectors are present.
If you see 3 Connectors, your engine is a JTEC version.
If you see 4 Connectors, your engine is an NGC version.
Why the Change? Changing to the NGC (Next Generation Controller) brought improvements in processing power, cost efficiency, reduction in number of different modules/controllers into a single more advanced unit.
Computing power was increased to comply with stricter emissions standards, reduce costs, and improve timing.
See below for sample photos of both versions of PCM’s to assist you in verifying.
If you need assistance, reach out so we can help you.
Inspect Your Crank Reluctor Wheel
01
Locate Crankshaft Reluctor/ Tone Wheel
Remove oil pan and look at the end with a large ring with nubs/ teeth.
Count the Teeth
It’s tough to see and count all the teeth. If they are spaced out, you have 16. This is a JTEC.
Review Samples Below
I have the JTEC and NGC versions for your review. It will be obvious to tell the difference.
Crankshaft Wheel Reluctor Tone Ring
Samples of how they look installed in the Short Block and on the Crankshaft.
Dodge Jeep 4.7L
Cam Target Wheel
Third way to verify the difference is by inspecting the Camshaft Target Wheel. Located behind the Camshaft Sprocket on the Right Cylinder Head.
JTEC 16-Tooth
JTEC Cam Wheel has 1 Window near the Timing Mark
NGC 32-Tooth
NGC Cam Wheel has 2 Windows near the Timing Mark. Often stamped NGC.
Not Interchangeable
The Target Wheel or Tone Wheel sends position signals to the PCM for ignition and fuel injection timing. Correct version must be used.
Use these Dodge 4.7 Camshaft Target Wheel graphics to locate the Target Wheel and compare the Windows/ Slots on your current 4.7 engine.
Once we have verified your engine is a JTEC or NGC version, we can provide you with the correct Remanufactured replacement engine.
Purchasing a Dodge Jeep 4.7 Engine
Now that you have inspected and examined the three key areas- the PCM, Crank Tone Ring, and Cam Target Wheel- you should be confident about which Dodge Jeep 4.7 engine you own.
You are ready buy the correct version, it’s time to contact us.
We sell Short blocks (bottom end only) and Long blocks (heads and block).
Here are links to both versions:
Buy Dodge Jeep 4.7 Short Block Engine
Buy a Dodge Jeep 4.7 Long Block Engine
If you still have questions Contact Us
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