Hemi swap using stock ECM-looking for help

[Buckminster]

I am trying to sort out a factory based swap on a '73 Challenger. I have an engine out of a 2006 Charger and an ECM out of a 2007 Charger R/T. I was told that the 2007 ECM does not need the ABS module or front computer to run, so it can be used on a swap like this with only one computer installed. I have looked at a couple of Youtubers that have provided details on how to install this and have everything working except it won't crank or fire the fuel injectors or coils. I have also purchased HP Tuners software and paid for a license to update the ECM. I've turned off the SKIM, saved the tune and then saved it using the Disable SKIM for retrofit. I've toggled the starter to enable using a Relay. if anyone has figured out this combination, would love some pointers.

 

[Katfish]

I was told it won't run without the O2 sensors, does it actually turn over, and just not light off?

 

[scar426]

Not to be a naysayer or Debbie Downer, but..... Personally I would not mess with a factory harness and ECU. I have used a couple of Harness and ECU (05-09 i believe) truck ECUs with 545rfe transmissions with zero issues (From HOTWIREAUTO.COM). I see you have the motor mated to a what looks like a NAG1 transmission (may be an 8-spd), that will absolutely require an ABS module to work, and several other components. If your thought is to save money by using what you have, more power to you, but in the long run you would be better off with an aftermarket harness and ECU (and a 545RFE transmission). Just my 2 cents.

 

[Challenger RTA]

Just did a quick used parts search. Is it for a
Electronic Control Module, 5.7L
Electronic Control Module, 6.1L My They are different. 2¢.

 

[Challenger RTA]

So now your up to 4¢. When do you make change?

 

[Challenger RTA]

I was looking at some pin outs for some ECM's. Some have a number of grounds. like 4 or more. I don't know if they all tie together as one. I would have to look into it more. It comes down to. Ground control to Major Tom. I say this because nothing works.

 

[sixpactogo]

I would contact Chris at Hotwire.com. He is very knowledgeable on these swaps. He will have some answers for you. He answered all of my questions back in 2015 when I did my swap. The Nag 1 was not an option then nor was any ECM other than the 2005 truck module. Many upgrades are available now.

CONTACT

 

[Buckminster]

Not to be a naysayer or Debbie Downer, but..... Personally I would not mess with a factory harness and ECU. I have used a couple of Harness and ECU (05-09 i believe) truck ECUs with 545rfe transmissions with zero issues (From HOTWIREAUTO.COM). I see you have the motor mated to a what looks like a NAG1 transmission (may be an 8-spd), that will absolutely require an ABS module to work, and several other components. If your thought is to save money by using what you have, more power to you, but in the long run you would be better off with an aftermarket harness and ECU (and a 545RFE transmission). Just my 2 cents.

Yes, Chris at Hotwire was super helpful. I will likely use his setup. the transmission on the stand is a 2019 8HP70. This is an unnatural combo. However, for this setup, I'm just trying to make the engine run. My car is in the body shop, so this is a mental exercise to see if I can make this run without buying his harness yet while I am waiting for the car to come back. Yes, I am aware of the grounds and have the 2006 factory shop manual, so I have all the wiring diagrams and pinouts. However, I was told that the 2007 ECU does not need the body control module or ABS module, so it is "supposed" to be an easier conversion.

I was told it won't run without the O2 sensors, does it actually turn over, and just not light off?

It has the O2 sensors plumbed and no O2 codes. It will turn over if I ground the starter relay, but the ECM won't fire the starter relay. If I manually ground the starter relay, the ASD relay closes but it will not fire the injectors or coils. I suspect it is a security thing. I have been using HP tuner, but am new to HP tuner.

Thank you very much for the feedback.

 

[scar426]

Yes, Chris at Hotwire was super helpful. I will likely use his setup. the transmission on the stand is a 2019 8HP70. This is an unnatural combo. However, for this setup, I'm just trying to make the engine run. My car is in the body shop, so this is a mental exercise to see if I can make this run without buying his harness yet while I am waiting for the car to come back. Yes, I am aware of the grounds and have the 2006 factory shop manual, so I have all the wiring diagrams and pinouts. However, I was told that the 2007 ECU does not need the body control module or ABS module, so it is "supposed" to be an easier conversion.

It has the O2 sensors plumbed and no O2 codes. It will turn over if I ground the starter relay, but the ECM won't fire the starter relay. If I manually ground the starter relay, the ASD relay closes but it will not fire the injectors or coils. I suspect it is a security thing. I have been using HP tuner, but am new to HP tuner.

Thank you very much for the feedback.

Yup I would suspect it's a security issue as well. I had bought a pallet set up from Cleveland Power and performance (2012 scatpack) and it fired right up on the pallet no issues but i know they tweak the security settings to make it run. Good luck.
(I/m currently working on a 6.4L 8HP70 swap into my Cuda but going the Mopar Performance harness and SGE transmission controller, have yet to fire it up, but so far it has been a bit more painful than Chris's setup, lol)

 

[Buckminster]

Yup I would suspect it's a security issue as well. I had bought a pallet set up from Cleveland Power and performance (2012 scatpack) and it fired right up on the pallet no issues but i know they tweak the security settings to make it run. Good luck.
(I/m currently working on a 6.4L 8HP70 swap into my Cuda but going the Mopar Performance harness and SGE transmission controller, have yet to fire it up, but so far it has been a bit more painful than Chris's setup, lol)

Would love to hear how your project goes. What rearend ratio are you going with?

 

[scar426]

Would love to hear how your project goes. What rearend ratio are you going with?

I have a 3.23 8 3/4. Not planning on changing it until maybe after the car is back on the road and i gauge how i like them with the 6.4l. I had a 512 stroker 6pack that blew a head gasket. Opened her up and found a lot of issues so decided to use the 6.4l I had already. Plus I'm sure I'm going to like the 8spd over the 727 3speed, lol.

 

[SFEbody]

I have a 2017 5.7 with the 8HP70 trans, And as others have said Chris Squires at Hotwire or Russel at Sound German both work hand in hand to make Gen3 hemi engines and trans work in old Mopar muscle cars. I have this set up and the support when you call Cris is amazing. I would not buy anything else no matter how much less it is. WHen my 8HP70 was not working Initial, they dialed in remotely to make changes to the programing on a Saturday..... that shoud be enough to go with them

 

[Buckminster]

Update: I just got it fired and running. the throttle works too. However, the wiring is not consistent with the wiring diagrams in the factory shop manual. that has me a bit perplexed, but it works. The manual shows that in the start position, that the C1 connector pin 30 (yellow wire) should be energized only during the key in the start position, which should trigger the relay for the starter (using the C3 connector Green/Orange wire to ground the starter relay. manual is from a 2006, but i'm using a 2007 ECM. I would not expect that to make a difference, but it appears to. I don't have access to a 2007 Charger wiring diagram... yet.