Mopar OEM EFI

-

Gryzynx

Senior Moment
Joined
Jul 21, 2009
Messages
777
Reaction score
9
Location
gone
I'm working on my first Mopar project in many years. How things have changed! My project is a '68 Cuda notchback, just like the one I had 30 years ago and never should have sold. In the old days, I swapped the 318 for a 360 from a '70 Fury and proceeded to seriously jeapordize my driver's license. One option I'm considering today is the 360 Magnum. I'm sold on EFI and I'd like to use the OEM Mopar EFI, but I'm finding there is very little info on using this system. What info I do find is not very encouraging in that there are issues with security systems, instrumentation and performance reprogramming. I've had some experience and success with Ford and GM EFI, so I'm not completely clueless and I'm aware of the options with aftermarket ECM's and carburated options, but I'd like to give the OEM system a try. Some of the questions I'm looking for answers are; Which modules will I need? Is the factory ECM to engine wiring a separate harness, or is integrated into the main vehicle wiring? What parts will I need to salvage from the donor vehicle? Mass air or MAP, (or Mopar equivalent terms). If this has already been dealt with on this forum, my apologies and I'd appreciate a link as my searches did not turn up much info.
 
Sorry for the bump, but thought I'd try this again.

Went to the wreckers and had a look at a potential donor. '98 truck, 360 Magnum. Noticed computer to the passenger side, relay box to the driver's side. Wiring runs along the firewall, branches down behind the engine. Looking at taking the complete setup and everything on the firewall. Hope this will gather all the necessary parts. Also will take the accessories, serpentine drive, alternator, A/C compressor PS pump, exhaust manifolds, sensors, starter etc. Yard says $1200 for everything, they will pull, sounds fair to me. Am I missing anything? Any info on splicing the new accessories into the old Cuda A body systems, (A/C and PS). Can I use the late model exhaust manifolds? Any clearance problems with the FI manifold? I'm swapping my old /6 K member for a spool type from a 74 Dart V8.

I'd appreciate any help I can get here, thanks.
 
I've never done it with the factory ECU but you will need a high pressure fuel pump and plumb the return line somehow into the tank. I've heard of people plumbing the return line into a welded in bung in the filler neck or a vent line.

Using the stock ECU maybe a problem as they have two sensors as it is OBDII, one before the cat and one after. If it doesn't get the proper signals, it could throw codes and refuse to act properly. That's just one factory pitfall. I have no idea what would happen without the factory speed sensors, ABS, different tire sizes, etc. As far as tuning the system I know that some places can get in and change the firmware, but I'm pretty sure you have to send it in for any changes.

Personally, I'd blow off the factory system for a Megasquirt set-up. That's what I plan to do with my truck someday. There's a member here who works for a company that makes a kit utilizing the megasquirt system, I think it's Madscientistmatt and I'm sure he could give you a wealth of information.
 
as far as I can tell, you can use the magnum v6 or v8 harnesses interchangeably, with the exception of adding an additional wires to the v6 harness for the v8. The computers are supposed to hook to any of the aforementioned harnesses. The only problem you may have is getting the trans working right, unless you get it out of the donor vehicle. You might want to make sure they get all the wiring goodies out from under the dash, too. ALSO.. if you wanted to make it work, the intrument cluster from a 93 Dakota will almost fit into the same place the one on my 72 dart is.. I think it could be done with some minor tweaking. That's just something to consider.

Also there are a lot of other EFI systems out there. From what I can tell, Megasquirt is good and you can find that on auto-nomics.com.. then there's Fastmanefi.com, another site called affordable-fuel-injection.com, let see... well there was customefis.com - but their account has been suspended, so that site must be a dud. Some of these sites offer more than just megasquirt, etc. check em out. One cool thing about them is that they are easier to modify for turbos, superchargers, etc than the factory MPFI.
 
If you had the room, Pick up the whole truck.
That way you can take as many pictures as you need to complete your project and have all the info....

I think the hardest parts of the project is going to be Defaulting anything your not going to be using.

Great idea...Keep us up to speed on how it's going.....

:read2:
 
Thank you very much for the replies. Of course, I've got more questions.

Is the Mopar ignition system integrated into the ECM? What type of signal is available from the distributor? I'm sure there must be aftermarket options.

I've heard a little about the Megasquirt ECM. Looks very interesting. I was hoping to use the OEM ECM to minimize the learning curve for tuning. I'm planning to drive the car as opposed to any sort of racing effort, so the flexibility of tuning the Megasquirt box may be a little less important to me. Looking at the donor truck, I did not see anything I could identify as a mass air sensor, so I presume the Mopar setup is speed density or equivalent? Might be important to know if I'm searching for an aftermarket ECM. Also, does anybody know what size, (lb/hr) the factory injectors are?

Still, sounds like the Mopar ECM does indeed integrate a lot of systems that will not be present on my Cuda. Megasquirt may simplify my installation. Gauges will likely be aftermarket, Autometer or equivalent. I'd like to run a manual transmission, possibly a Tremec, or maybe an Aisin R154 using the 3.9 V6 bellhousing. The car currently is an automatic and if I remain with an automatic, I'll probably use a 904 that I already have. That brings up the issue of the ECM once again as I understand the Mopar unit controls the overdrive automatic. Might need some loopbacks to make it work?

Looks like I've got a lot of learning to do, thanks for your help.
 
I thought Mopar Performance was doing a plug and play for just this swap? The ECU was supposed to be programmed to eliminate the O2s and downstream cat monitors. They haven't released this yet? I thought that's what MA's Savoy was supposed to be: a test bed for MP to get this all out to the public.
 
Personally, I'd blow off the factory system for a Megasquirt set-up. That's what I plan to do with my truck someday. There's a member here who works for a company that makes a kit utilizing the megasquirt system, I think it's Madscientistmatt and I'm sure he could give you a wealth of information.

That would be me. Right now getting it to work with the factory distributor is a bit experimental but there's 1 or 2 examples running around. Earlier Lean Burn distributors are a cakewalk to deal with though. I have one on my slant six MegaSquirt powered Dart.

As for what other systems can work with the factory distributor (some of the less expensive ones will require substituting a dual sync) - I know Haltech will, I think BigStuff3 might, I know the Holley, Accel, and FAST systems won't. Not sure on Edelbrock's - it's based on the very high end EFI Technologies system, but they may have locked you out of a lot of its features to simplify things. The factory EFI has an eight tooth crank wheel and a one tooth wheel in the distributor.

If you're going with an OEM ECU: An OBD-I ECU might be easier to swap over, but there's no tuning options. SuperChips makes tuners for OBD-II, but you have to swap over more sensors. Often, tuning factory EFI beyond some basic adjustments has a pretty steep learning curve compared to standalones. It depends on whether you want to get it up and running, and leave it close to stock (an OEM PCM would do that just fine) or want a modified and tuned engine. I'd probably use a manual transmission PCM - that way it won't care about the trans. The ignition is completely built into the PCM except for the coil and sensors; there's no external ignition module.

More notes - I believe the PCM just controls the tach and no other gauges, and can probably drive most aftermarket tachs. They are all speed density; Mopar hasn't been a big fan of mass air flow sensors.
 
Well. in a couple of hours, I'm off to pick up the car. eBay purchase from Texas, so I'm hoping for a minimum of rust. Item 230351698409 in case anyone is interested.

I had an interesting call from my local Dodge dealer. I ordered a book on the Magnum engine and found out the book is no longer available from Mopar performance? Apparantly very little is now available in the way of books, possibly a result of the bankruptcy? Good thing there are forums like this, thanks again for your help.
 
-
Back
Top