I am doing an engine swap from a 2003 s-10 blazer and putting that engine into a 1999 s-10 blazer (both 2wd/auto - 4.3/4l60E) I know the wiring harness and computer systems are different, so I am trying to stay all 99 parts. To do this I plan on swapping out the intake manifolds so the 2003 eng/trany has a 99 intake manifold. This should take care of most of the differences except for one! THE Knock sensor on the back left side of the blocks!!! the 03 has a 2 prong (3 wires) sensor with a bolt style attachment, and the 99 has a 1 prong (1 wire) sensor. Question: can I drill and tap the 03 block to accept the 99 style sensor? or should i take the time to pull the ENTIRE wire harness/computer from the 03 and install it into the 99 (huge pain in the *!#)
you help is appreciated I am working the project today and this is the only thing I have holding me UP (3/29/09 3:20pm central)

 

If it looks like you have material to drill and tap for the 99 sensor, then yes, you should be able to do it. I have not had the pleasure of attempting this though.

 

Well, thank you for your advice, but I went the long way around-
There were too many differences from the 2003 to the 99 blazer to just swap knock sensors and the intake manifold. So... COMPLETE wire harness swap - from tail gate to fuel tank! - (along with the anti-lock brake system, brake reservoir, hard brake lines, front brake hoses, o2 sensors, left exhaust manifold, dash, Went with the 03 column and floor shifter also... I figure all of these items had different plugs from the 99 and its easier to pull all the wires then to cut and splice hoping they kept the wire color combos the same. Also, some systems had more/less wiring to them or different sized connectors (brake lines for example) so why waste the time of trying to make it work when one could just swap everything...
But just so everyone knows, it can be done and relatively easily... so don't let buying parts cars stop you just because someone tells you that things wont interchange- they will if you buy the whole car as a parts car!
SO, now my 99 blazer with 185K on the body and a bad transmission has an 03 everything with 52K on the clock

OH and one last thing, I had a column key failure. the key would not turn. it turns out it was a very simple problem and solution. Thought it was a security issue but was not. It was a "wal-mart" key and would not engage the lock tumblers completely (it use to, but for some reason stopped working) The Lock tumbler from the 99 column shift type column will work on an 03 floor shift type column. GM calls out a different part # but they are the same lock barrel (one has the finger tabs the other doesn't - thats the only difference). so maybe that will help some of the people with key wont turn issues.

 

Way to make work for yourself... Glad you got it done, but it would have been far easier to do the modification required on the motor. It has been done before without swapping everything over.

God help the next person that owns your truck. Hope you disclose the whole 99 with 03 guts thing.

 

guess I need to abide by some rules here real quick for the classifieds...

up date you all anyway..

so I have had ZERO issues with the swap from a 2003 4.3/4l60E into a 1999 4.3 4L60E.
Everything was swapped in afternoons after work for about 3 hours a night and was completed 3 days short of a month (approx 70 to 80 hours) yeah thats not good but you know this was in a low light garage, with basic hand tools, a drop light, and some jackstands... I had to buy a cherry picker but that was it...

SO dont be lazy all... GET 'ER DONE... bought a lightly wrecked blazer with 57K miles on it and swapped it all over to a 185K blazer ... SO approximately $2000.00 later I have a new style blazer (newer interior, swapped out heater core, swapped out dash&gauges, carpet, brake system, engine, tranny, wire harness, computer, cruise controller - litterally everything)

buy a 500.00 car and sell it for 300. for a spare and your good to go!!!
why pay 8K for a different one...

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