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Discussion Starter · #1 ·
Sorry if I'm posting this in the wrong spot I just need some help with the 3.9 to 5.2 swap. I have a 2002 club cab Dakota slt with the 3.9 I have a 5.2 I got for free out of a 97 ram 1500 my main question is do I need a 2002 Dakota rt engine computer or can I use any year Dakota rt engine computer with my truck to get it to run right and drive right. And do I need a oil pan for a 5.2 Dakota or will a Dakota rt oil pan work on my 5.2 ? My truck is also an automatic it has the 42re in it. Any info is appreciated thank you
 

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Sorry if I'm posting this in the wrong spot I just need some help with the 3.9 to 5.2 swap. I have a 2002 club cab Dakota slt with the 3.9 I have a 5.2 I got for free out of a 97 ram 1500 my main question is do I need a 2002 Dakota rt engine computer or can I use any year Dakota rt engine computer with my truck to get it to run right and drive right. And do I need a oil pan for a 5.2 Dakota or will a Dakota rt oil pan work on my 5.2 ? My truck is also an automatic it has the 42re in it. Any info is appreciated thank you
My son and I did a 3.9 to 5.2 swap this summer. His truck is a 2000 Dakota 4X4 with 5 speed.

The donor 5.2L was from a ‘98 Durango we got for cheap. As such, we had the associated ECBCU, and wiring harness to get the 5.2L running.

I can say from our experience, no oil pan change was needed. The mounts were in the same locations, so even exhaust mounted the same.

One issue we did have was “defeating” the security system. Until we did that, the engine would start, and then die after 3-5 seconds. Our issue was our truck didn’t have security, and the donor Durango did. If I understand correctly, if a ECM has ever been connected to a BCU that had security, the ECU would not allow injectors to fire unless it could communicate with a BCU with security. The fix was installing the Durango high end BCU, modifying the wiring harness to work with our base model equipment, add communications wires between BCU and ECM, and grounding a wire. I can tell you what wire to ground later.

So, from my perspective, you need a 5.2L ECU, wiring harness, and possibly another BCU.

I live in Houston. There is a salvage yard here that sells ECMs for $40. I picked up a couple a while back. I’d be happy to go to the yard, get an ECM and wiring harness (you just pay for parts and shipping). I’d put ECM on my son’s truck to make sure it works. If you could send me a picture of the sticker on your BCU ( aka CTM for the Dodge die hards), I could help you get things together.

Since my son’s truck was a 5 speed, and the only ECMs I could find at the salvage yard were for automatics, we still have some DTCs related to automatic transmissions. The truck runs fine. I’m working on the codes. Since you already have the automatic transmission, you are one step closer to finding ECMs that will work.

One more thing: I saw you use the term “RT “ several times. A 5.2L is not from an RT vehicle. If it was a true RT, it would be a 5.9L. If you confirm it is a 5.2L (318), I can offer lots of help. The V8 swap has made the truck so much more fun to drive. I recommend it to anyone who can.
 

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Discussion Starter · #3 ·
My son and I did a 3.9 to 5.2 swap this summer. His truck is a 2000 Dakota 4X4 with 5 speed.

The donor 5.2L was from a ‘98 Durango we got for cheap. As such, we had the associated ECBCU, and wiring harness to get the 5.2L running.

I can say from our experience, no oil pan change was needed. The mounts were in the same locations, so even exhaust mounted the same.

One issue we did have was “defeating” the security system. Until we did that, the engine would start, and then die after 3-5 seconds. Our issue was our truck didn’t have security, and the donor Durango did. If I understand correctly, if a ECM has ever been connected to a BCU that had security, the ECU would not allow injectors to fire unless it could communicate with a BCU with security. The fix was installing the Durango high end BCU, modifying the wiring harness to work with our base model equipment, add communications wires between BCU and ECM, and grounding a wire. I can tell you what wire to ground later.

So, from my perspective, you need a 5.2L ECU, wiring harness, and possibly another BCU.

I live in Houston. There is a salvage yard here that sells ECMs for $40. I picked up a couple a while back. I’d be happy to go to the yard, get an ECM and wiring harness (you just pay for parts and shipping). I’d put ECM on my son’s truck to make sure it works. If you could send me a picture of the sticker on your BCU ( aka CTM for the Dodge die hards), I could help you get things together.

Since my son’s truck was a 5 speed, and the only ECMs I could find at the salvage yard were for automatics, we still have some DTCs related to automatic transmissions. The truck runs fine. I’m working on the codes. Since you already have the automatic transmission, you are one step closer to finding ECMs that will work.

One more thing: I saw you use the term “RT “ several times. A 5.2L is not from an RT vehicle. If it was a true RT, it would be a 5.9L. If you confirm it is a 5.2L (318), I can offer lots of help. The V8 swap has made the truck so much more fun to drive. I recommend it to anyone who can.
Ok cool it's gonna be a little while before I do it but I'll get some pictures of the bcu this weekend and send em to you I appreciate the help
 

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My son and I did a 3.9 to 5.2 swap this summer. His truck is a 2000 Dakota 4X4 with 5 speed.

The donor 5.2L was from a ‘98 Durango we got for cheap. As such, we had the associated ECBCU, and wiring harness to get the 5.2L running.

I can say from our experience, no oil pan change was needed. The mounts were in the same locations, so even exhaust mounted the same.

One issue we did have was “defeating” the security system. Until we did that, the engine would start, and then die after 3-5 seconds. Our issue was our truck didn’t have security, and the donor Durango did. If I understand correctly, if a ECM has ever been connected to a BCU that had security, the ECU would not allow injectors to fire unless it could communicate with a BCU with security. The fix was installing the Durango high end BCU, modifying the wiring harness to work with our base model equipment, add communications wires between BCU and ECM, and grounding a wire. I can tell you what wire to ground later.

So, from my perspective, you need a 5.2L ECU, wiring harness, and possibly another BCU.

I live in Houston. There is a salvage yard here that sells ECMs for $40. I picked up a couple a while back. I’d be happy to go to the yard, get an ECM and wiring harness (you just pay for parts and shipping). I’d put ECM on my son’s truck to make sure it works. If you could send me a picture of the sticker on your BCU ( aka CTM for the Dodge die hards), I could help you get things together.

Since my son’s truck was a 5 speed, and the only ECMs I could find at the salvage yard were for automatics, we still have some DTCs related to automatic transmissions. The truck runs fine. I’m working on the codes. Since you already have the automatic transmission, you are one step closer to finding ECMs that will work.

One more thing: I saw you use the term “RT “ several times. A 5.2L is not from an RT vehicle. If it was a true RT, it would be a 5.9L. If you confirm it is a 5.2L (318), I can offer lots of help. The V8 swap has made the truck so much more fun to drive. I recommend it to anyone who can.
that's the bcu in my truck sorry it took so long to reply
3473
 
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