4.3 engine swap
 

Greetings, I'm getting ready to pull a 4.3 vortec outa my '98 s10 blazer 4x4 & install it into my '99 s10 blazer 4x4. Question: do I need to use the '98 pcm with the '98 engine? Any tips are very appreciative.

Best way to be sure things are right is to use your original PCM, original wiring, original intake, original exhaust manifolds, and original engine accessories for the vehicle. Only use the long block from the donor vehicle. You need change those lower intake gaskets anyway with the good rubber/metal Felpro ones. The rest of any internal differences between 1998 and 1999 are irrelevant to the swap.

just double checking
 

Thank you so much for the info. So which PCM do I use? Do I use the PCM that is matched to my donor engine, or does that even matter?
And my donor engine isn't equipped with the air pump that is plummed into the exhaust manifolds ( since the engine I'm pulling out does have the air pump. can I get rid of the pump or is that a no-no?
And another question: the '98 & '99 s10 blazer 4x4 are equipped with a 18 gallon fuel tank correct? If so, I am only able to put 10 gallons of fuel in ( when on empty) , & the sending unit is working correctly in accordance with the fuel gauge in my dash.
I appreciate any help or info.

He!! yes, it matters! Like I said before, use all the accessories - intake/exhaust manifolds, air pump, PCM, wiring, etc from/for your original engine. Again, only use the stripped long block from the donor 1998 vehicle and transfer everything over. Keep the A.I.R. pump and the rest as originally installed and functional on your 1999 or you will have a SES light on and codes set.

Once engine is installed you will need to have a crankshaft relearn done with a capable scanner because you now have a different engine/crank sensor and the old calibration will no longer be valid. Until that is done, you will probably have the SES light on, be setting false P030x misfire codes, and the PCM will run in a failsafe mode without TCC and other things enabled.

Someone else will have to answer on your fuel tank question.

Good luck and best wishes for a successful engine swap. Take lots of photos as you go and take your time! It's not an easy one to do.

My 2 door has an 18 gallon tank. At 1/8 tank on the gauge it takes 15 gallons to fill. New spectra tank and delphi pump assembly last summer.

With my fuel light on, most I can pump in is 13.5-14 gallons.

Hopefully there is a few extra gallons left in there if I'm ever on "E", and need to make it to a gas station. :icon_nut: