This is my first swap... Help

[meglaman]

I'm putting a 91 350 tbi into my 94 vortec astro van. I need help with the engine wiring. What computer do I use and which wiring harness?
ANY help would be great. Thanks

[dave w]

This link has wiring diagram information: http://www.gearhead-efi.com/Fuel-Inj...Information-0D

If the old Astro Van engine is a 4.3 TBI engine, the conversion to a 91 350 TBI will be fairly straight forward nuts and bolts stuff. Basically you can use the Astro Van Harness (with very few modifications if the old engine is TBI) and Astro Van Computer (with a V8 Memcal and custom programmed PROM Chip). Most of the sensor connectors are the same for the 91 350 TBI engine and 94 4.3 TBI engine.

dave w

[meglaman]

My 94 Astro had a 4.3 vortec in it. Totally different injection system.

[dave w]

I'm thinking the 94 Astro has the 4.3 CPI system, with One Injector and 6 poppet valves?

I'm thinking your harness can still be used, with some modifications. I'm thinking your harness will need two injector control wires, maybe re-pinned and maybe some sensors will need re-pinned also. The 1994 4.3 CPI system with automatic trans uses the same computer as the 1994 TBI system with automatic trans, except the computer Memcal is a different part #.

There is also the option of using an aftermarket TBI wiring harness from Fuel Injection Connection: http://fuelinjectionconnection.com/gpage.html

I think splicing and re-pinning wires in your harness would be a lower cost option?

dave w

[meglaman]

Ya I checked into the premade harness and they are spendy.. So where should I start? I have my ECU and harness out.

Thanks a lot for the info. I finally feel like I'm headed in the right direction.

[dave w]

I would start with the "Known" harness differences, like the TBI injector wiring. Then work through each sensor. Maybe you can re-purposed a wire, like re-purpose the EGR wiring to become an injector wire?

dave w