I'm looking for a good number of parts and where to get them. I'm looking for fuel injectors, but I think I saw somewhere that there are rebuild kits for them and can't find it again. I'm also looking for a fuel-sending assembly and can't find one. Also, are all the spark plugs the same? I could also use some new harnesses instead of all this janky wire repair. Any recommendations for a fuel tank replacement? Where to get trim parts? I'm sorry if a lot of these are super obvious and I'm just dense. I chose to try and ask all these in one post instead of spam asking questions in feed. This car has been sitting for about 2 years and needs some love.

 

Injectors - I've had a local fuel injection specialty company rebuild them, and I've also "rebuilt" them myself by dumping them in an ultrasonic bath and using generic EV1 injector rebuild kits, which are basically just the external o-rings, an new pintle cap, and a new filter screen. If you need to replace the injectors entirely, you can buy them from places like RockAuto or what have you

Fuel sending assembly - I don't think you'll find an entire unit brand new anywhere at this point, best to rebuild what you have. You can buy the pump, screen, and hanger gasket new. If you want to replace the hanger entirely, there's pretty much just the JDL MFG dual pump option which might be overkill for you, and you still need to transfer over bits like the fuel level sender over to it

Spark plugs are separated leading (bottom of engine, heat range 7) and trailing (top of engine, heat range 9), using NGK part numbers BUR7EQ and BUR9EQ respectively. You'll need 2 of each

Wire harness availability depends on your year and model, but there's very few NOS harnesses remaining. I'm out of the loop but there might be aftermarket options. All else failing, you can always build your own. There's a lot of good online resources on how to nowadays, I usually point people at HPA or superfastmatt's video on the matter

I don't think anyone makes an aftermarket replacement fuel tank for these cars that just drop in, but someone can correct me if I'm wrong. If you buy a replacement, do mind the fact that the tanks are different sizes between S4 (1986-1988) and S5 (1989-1991), and so are the hangers

For trim, I don't think anyone does it aftermarket. You'll have to source NOS OEM parts. See below

As far as sourcing parts in general, if you want OEM, a long-time friend of this forum is Ray Crowe of Malloy? Mazda. You can also purchase OEM products from Mazdatrix. Atkins Rotary also supplies a lot of parts for our cars, but has gotten a bad rap for passing off reproduction parts as OEM. If you're determined and need to source something expensive OEM, you can also try looking for it through Amayama or other sourcing options in Japan, which are often cheaper even after the atrocious shipping. RockAuto has some parts for our cars, although it tends to get confused about the terminology so you might have to dig for things, like it lists a replacement oil pump chain under timing chain. Plenty of aftermarket parts companies as well, many have come and gone, so I'm not super up to date on that anymore

 

there are a few guys that part these cars out that you could get most of the items you list from. just be warned, they arent cheap. look up on facebook either riggs vintage mazda or auscan industries. both these guys are located in canada but ship internationally