90 EFI SD swap to a TBI 84 Town car

[over2tonsofFun]

My wife's 84 Town car has been having transmission issues. Some slight engine issues.(burning oil) It maybe do to it sitting in a field for 5+ years.

We have found a 90 Grand Marquis with front end damage ( mostly cosmetic) for a good price. We are thinking of getting it and swapping the Engine/transmission into my wife's car. So she could get an EFI car.

Other than the big thing what would be needed to be swapped from the SD EFI to the TBI town car?

Tim

[86VickyLX]

My wife's 84 Town car has been having transmission issues. Some slight engine issues.(burning oil) It maybe do to it sitting in a field for 5+ years.

We have found a 90 Grand Marquis with front end damage ( mostly cosmetic) for a good price. We are thinking of getting it and swapping the Engine/transmission into my wife's car. So she could get an EFI car.

Other than the big thing what would be needed to be swapped from the SD EFI to the TBI town car?

Tim

You need the ecm, the engine harness, the engine and trans being swapped would be the easiest thing. However, you will need to swap the 84 shift linkage onto the 90 trans, you will also need to get a 86-89 tv mounting bracket (part of the shift linkage that bolts to the outside of the trans, and lever unless it's the same on the 90+ I'm pretty sure the whole mounting set up changed when they went to cable shift.

An EVTM for both your car and the 90 vic/grand marquis will be very very helpful.
Throttle cable, TV cable and cruise control cables will be needed from the 90 as well.
Realistically, you just need to hook up, key on power, crank power, ground. If your towncar has digital dash, you will need to add the fuel flow wire to pin 34 of the ecm harness, you can rob that from your original harness. You will also tie in the low oil pressure warning and coolant temp warning as well. You may need to swap the senders to your original application as they might be different depending on what set up the towncar has be it digital or analog instrumentation.

[gadget73]

The 90 trans has some internal upgrades over the 84 one too, so thats another good reason to swap if it works properly. And yeah the shifter lever has to change, but thats not all that difficult.

https://youtu.be/_6UX9itv1NM

explains it easier than I can type out a bunch of stuff.


I think the digital dash stuff is just idiot light on/off switches. Same oil pressure unit, 90 GM had a temp gauge tho so that has to change over.

The start circuit is slightly different. 84 I believe is not part of the ECM harness, in 90 it connects in there somehow. Need an EVTM to figure out where the connection is. Entirely possible you can just splice them at the starter relay, not 100% on that. It will work if you don't connect the start circuit into the ECM but it will run funny on initial startup.

[over2tonsofFun]

The plan was to do engine and trans swap. But on the drive home with it. My wife decided that we are going part out the Lincoln. Keep the Marq. Fix the front end.



She runs fantastic.

Tim

[gadget73]

if the 90 is more solid, thats the easier choice. Rust level would mostly be my guide.

[over2tonsofFun]

Only problem with the Grand Marquis is the header panel damage and the bad clearcoat. Minor problems with the windows. Nothing I can't handle.

Tim