Cadillac: 85 Eldorado Convertible, engine swaps, correct connector

Question
Dear Tom,
My '95 Sedan DeVille, 4.9 is by far the best car I have ever owned (I'm 64, and have had many cars, including 5 Cadillacs). I am going to need an engine for my '85 Eldorado pretty soon. I would LOVE to replace the 4.1 Eldo engine with a 4.9--Am I dreaming? Isn't the 4.9 a pretty tough engine and not subject to the same stigma as the 4.1? My '95, 4.9 has 140K miles, and runs and drives exactly the same as when it was new.
Best Regards,
Paul

Answer
As you said, You ARE DREAMING. Back in our younger years we used to swap engines back and forth without any problems.

However with all the electronics that are on today's engines, This is a VERY VERY VERY complex, Costly and many many hours of work to install a different size engine. You would need to replace the computer(s) Change some of the wiring on the engine as well as back to the computer.

In my career, I did 2 and ONLY 2 of these kind of engine swaps and it took many many hours of changing wire locations on the engine and at the computer connectors and replacing the computers as the computers are also DIFFERENT for each size engine.

For example there are 3 large wire connections with about 30 wires in each connector.

Let's say that on one engine there is an orange wire in the BLUE computer connector marked A3 for the smaller engine, But in the larger engine this BLUE wire may be in connector marked F4.

You would need a complete electrical schematic for BOTH engines and BOTH computer systems and you would have to sit and check each and every wire to be sure it is in the correct connector position.

Like I said above, I did ONLY 2 and will NEVER EVER do another one as it was just not worth the expense and the vast amount of time involved.


PLEASE do NOT attempt this project unless you have a VERY DEEP POCKET and a HIGHLY SKILLED automotive technician experienced in this type of work.


autohelp