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90 s model swap to fuel injected

73 Views 3 Replies 4 Participants Last post by  1funryd
Hey Prelude Fam. I have had my 1990 Honda prelude S (yes carb :( ) since I was 15. I have had it sitting for a while and was trying to get it back up and running which I have but it’s not running good. One of the reasons I stopped driving it was a gassy smell would come even inside the car and didn’t want to risk it. As I’ve been putting $ into get it back road ready. I’ve been considering just doing the swap to fuel injected versus rebuilding carb. Any tips or pointers or maybe a post or thread? Anyone done it before? Can the transmission be kept? Any help would be great. Also and suggestions to the gas smell? I know gas cap, possible catalytic converter, possible carb and muffler( no holes though)
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Gas smell is likely from old rubber fuel lines or vacuum lines. I had a problem with a fuel smell and it ended up being over a dozen rubber lines that I had to replace. The car ran a lot better after I did that.
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There's a lot of information here on doing this swap. Check the FAQ sticky at the top of the 3rd gen forum page. There's also the site (Mustardcat's site). Here's a write-up from that site for the swap...
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Yup, that write up has been established decades ago.

But the main points:

  • B20a5 complete motor/ECU
  • Either replace the entire harness or just tap into the existing harness and wire up the essentials.
  • you will need to install a Fuel pump, And a return fuel line. PGM-FI Main relay, located under the dash. Its an important electrical partHere is an aftermarket version if you choose to just add parts that make it Si - Main Relay Conversion with Kill Switch

  • Fuel filter
  • Return fuel line, I used metal line routed under the car 10 Ft. or metal line
  • High pressure fuel line to replace the original fuel lines, 10 Ft.
  • High pressure fuel line to go from the fuel inlet pipe to the fuel filter
  • Fuel injector resistor
  • Igniter Unit
  • Vacuum Control Box - this part I believe you can by pass and just use a universal vaccum block to get all the necessary vaccum lines.
  • atmospheric pressure sensor (map)

Thats the just of the parts for the swap.
The write up tells you fairly detail on what to do.
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