The DeLorean needs routine maintenance and the occasional, more significant refurbishing. Beyond that there are also a number of customizations and upgrades to improve performance, reliability and functionality.
This post is the rough sequence that I used to get the car idling with TunerStudio, and then getting it driving. Something like this would have helped me a lot when I was trying to figure this out myself.
My first drive uncovered a few issues — stalling on acceleration and deceleration, excessive exhaust noise, bad brakes, TPS issues, a broken key, a squeaky belt, trouble starting in Park, a broken oil pressure gauge sender, fixing closed loop idle, replacing a leaking fuel line, fabricating a bracket for the oil dipstick tube, and running out of gas. Here I get all of those fixed, and finally bring the car home.
Diagnosing ignition issues led me to replacing the original bulkhead connectors used for the EFI wiring with a single, modern weatherproof one. This included building a new mounting plate with appropriately-sized holes for both the new connector and two of the original connectors.
I swapped out the old radio with a new double-DIN unit with a touch screen and Apple CarPlay compatibility. This was a it tricky, since the center air vents are where the radio needs to be. I relocated them to the knee pad and wound up needing to build a new air distributor to get the radio to fit.
Everything is pretty much done, so it's time to set up the initial MegaSquirt tune with TunerStudio. I also had to hook up some remaining cables, add fluids, fix a coolant leak, drain some bad gas, build some brackets and do a few other bits before I could finally turn the key.
After waiting too long for a muffler, I decided to build my own using off-the-shelf parts, with minimal welding and no bending, with the end goal being to have as quiet of an exhaust as I could make... within the bounds of every aftermarket part being labeled "performance", that is. It came out pretty good, but I have yet to hear what it sounds like...
Before I could wire up Josh's harness into my car, I needed to understand it, as well as make a few modifications for the automatic transmission and my particular car's electronics. This meant creating a new wiring diagram, after which I could replace the old engine wiring with the new and move closer to getting it started.
I'd installed some Dynamat before, but only in easily-accessible areas. With the electronics trays behind the seats removed for the EFI conversion, I had the opportunity to install Dynamat there as well.
Now on to the electrical modifications. The spark plugs go in pretty easy, and the coil-on-plug system fits just like the spark plug boots normally would. Before I could go any further than that, I would have to remove the old engine ECUs and related wiring to get ready for the MegaSquirt installation.
Vacuum routing on the 3.0L engine is simpler than on the 2.8L engine. In part this is because I removed the charcoal canister, so I no longer have a vapor recovery system (although I may add one later). I needed to hook up four things: the climate control vacuum reservoir, the automatic transmission vacuum modulator, the brake booster, and the MegaSquirt MAP sensor.
In order to pull the old ECU wiring, I needed to get under the center arm rest. This isn't particularly hard; it's mostly an issue of finding all the bolts, disconnecting all the wires, and making sure to move the harnesses away from the sides of the armrest before lifting it out.
The door struts are really easy to replace, but I spent a surprising amount of time trying to get the clip into the bottom of the strut in until I finally rotated it to point away from the car. After that the top end went on pretty easy. If not for that bit of trouble, this would have taken just a few minutes.
With the bottom of the engine swapped out and the top of the engine cleaned up, it now had to go into the car. Overall this wasn't too complex, beyond the trick of getting the transmission aligned with its mounts. It went pretty smoothly all told.
The fuel system was fairly easy to install. After relocating the fuel filter to the engine bay, I put the new fuel injectors into the fuel rails and mounted them back on the intake manifold, and installed that back on the engine. I built two new stainless fuel lines with AN-6 connectors to run from the rails to the existing hardlines in the car.
Right about the time I needed to figure out all the EFI hardware, Josh on DMCTalk.org just happened to be upgrading his 3.0L engine to an even larger one, and put all of his 3.0L conversion hardware up for sale. I bought everything that would aid in getting my 3.0L engine up and running.
In it's stock location, the DeLorean's fuel filter is not the easiest thing to get to, especially when rusted hardware is involved. I decided to relocate mine to the engine bay to make it easier to access, building new AN-style fuel hoses that would easily interface with my in-progress 3.0L EFI system. This also introduced me to rivnuts, a tool that makes it easy to add blind bolt holes.
I snapped off my automatic transmission's dipstick tube when reinstalling the engine and transmission into the car. Replacing it isn't too bad, and only requires a couple of bolts once you've raised the car and drained the transmission. Well, except for the fact that I stripped the bolt hole that holds the tube to the transmission thus requiring that I repair it first.
My automatic transmission always seems to leak, so I decided that while I was reinstalling the engine and transmission in the car that it would be a good time to replace the old-style cork gasket with a new silicone one from DeLorean Performance Industries.
While removing my engine, I noticed some surface rust. I soon found that a few points weren't just surface rust -- chipping away reveled a large hole on each side of the frame under the lower link arms. There was also rust inside some of the frame members, but the holes were what really concerned me. That meant welding clean metal over them, treating the metal, painting with POR-15, priming, and finally painting with a final coat of grey.
I didn't want to take the engine back out of the car once I got it in there, so before I went any further I decided to make sure the engine compression was good. This meant mating the engine and transmission so that I could use the starter to turn the engine, and learning how to use my previously-purchased but never before needed compression test kit.
Given the oil/coolant mix I was dealing with earlier, plus the age of the engine in general, I decided to swap out the water pump. I didn't realize just how little of the water pump is the pump itself -- the thermostat housing and back of pump need to be swapped with those from the 3.0L. Of course I stripped some of the bolts trying to remove the old hardware, but I eventually got everything assembled onto the new pump.
The rear main seal keeps all the oil from leaking out the back of the engine around the crankshaft. It's very hard to get to unless you already have the engine out of the car, and even then an engine stand can be in the way. Overall, I found the process easier than I had feared, with the most trouble being taking the engine off the stand so I could get access to it.
Installing the timing and valve covers is fairly straight forward. I wound up ruining my front main seal while trying to tap it in just a bit further, and had to replace it as well. The gaskets went on without much trouble with some Right Stuff, and I was able to reuse a lot of my stainless steel hardware from the 2.8L engine on the 3.0L covers. I also replaced the oil filter cap, but I still need to find an oil vapor separator to replace the one I broke when transporting the engine.