85rustbucket
Registered Member
Swapping out my carb 350 for an 87-up 5.7 TBI. What do i have to do to make everything work right; swap the wiring harness and such? Never really messed with fuel injection before, but im tired of beating on carbs.haha
CK5
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TBI Swappage
- Thread starter 85rustbucket
- Start date
85rustbucket
Registered Member
so basically tricking the motor into thinking its still in the donor truck.
That is usually the best solution! Your truck will have everything that the TBI engine computer will be looking for. If you run into trouble or need help with wiring etc, post up! Lots of us here have a lot of knowledge about these injection systems
plus the coil, EST module and a few other things.
Everything but the evap or air emissions systems would be required for a swap. VSS is often left out, but it is an important system. The TBI ECM does a bunch of calculations based on speed. Most notably keeping your engine fueled correctly during a sudden stop to prevent stalls, or keeping your idle up when you are creeping along with a manual transmission. It is also used for egr calculations and for tweaking the fuel / timing tables at speed as well as the torque converter lockup.
Yes, it'll run without, and fairly well at that, but you loose a lot of efficiency improving characteristics that will help with power, mileage and at speed engine response. GM did not include the VSS on their EFI systems just for the fun of it. It isn't even challenging to install one in these trucks either. The optical VSS fitted to the back of a mechanical speedometer is all it needs.
Yes, it'll run without, and fairly well at that, but you loose a lot of efficiency improving characteristics that will help with power, mileage and at speed engine response. GM did not include the VSS on their EFI systems just for the fun of it. It isn't even challenging to install one in these trucks either. The optical VSS fitted to the back of a mechanical speedometer is all it needs.
big pappa b
3/4 ton status
Will the VSS plug into the back on my 83 Jimmy speedo or do I require something else?
Depends on when they switched from the mechanical cruise module to the electric one. Either way, it would be easy to swap in a new speedometer with a VSS on it. I have even retrofitted a VSS to an old blue ring 100mph speedometer too
pull the entire harness including the fuse panel and dash as well as the engine and computer harness. Get all the parts from an old body style truck 87 thru 91, it will bolt in...Drop the stuff into your truck, hook up the fuel tank sender unit and fuel lines, and it will work. If you have a mech speedo, the vss plugs into the back of the speedometer.
I don't have a speedo on my setup, but I swapped everything else and it worked. The reason I don't have a speedo is lack of a cable that reaches the dash, aftermarket speedo that lacks the vss plug, and I have a np205.
I don't have a speedo on my setup, but I swapped everything else and it worked. The reason I don't have a speedo is lack of a cable that reaches the dash, aftermarket speedo that lacks the vss plug, and I have a np205.
454Sub
5/8 ton status
i swapped in a 454, had to cut and change the IAC plug to the 454 TB style, and it worked. I personally dont use a Egr, or a VSS. i also dont have the aftermarket burned chip for this. Not saying it runs perfect, but it will roast 2nd usin a TH400 with 39.5x18 boggers on the street. I learned the easiest way to do it is use as much of the donor as possible, and hook it up the same as GM did, and it will usually work like they wanted it too. Another thing, i used the charcoal canister because i got tired of the garage smelling like gas all the time
