Please help!!Knock sensor
 

I had recently bought a 98 jimmy vin W.As i was taking the distributor cap off to see if i should replace i pulled on a single wire and up comes the knock sensor which was sitting on the bellhousing.Now i went to reinstall it and surprise the hole were it goes is WAY to small.Now after some time and research im pretty sure at some point someone swaped the motor and i believe it might be from a 2003 blazer which has a smaller hole for a bolt on 2 wire knock sensor,and the 98 is supposed to have a 1 wire huge stud knock sensor.Now it would be a HUGE pain to tap this hole to fit the right sensor so will i be able to install the newer 2 wire ks instead?

I tried to find the outputs of each sensor but had no luck doing so.

You cannot substitute a 2 wire sensor for a single wire sensor. Their outputs are different from what I have read up on them. You will have to find a way to drill/tap the hole out to the appropriate NPT tap size (can't remember off the top of my head).

Theres no way to do this w/o pulling the motor(not looking forward to do that)

Only other thing i had in mind if i cant use the 2 wire is maybe put the ks on a lathe and mill it down and rethread it to the new size,.would be easier than pulling the engine and tapping it ehh?Or even using a fitting or two to downsize it..

And another thing if they did swap these engines is the 98 jimmy fuel pump the same pressure as a 03 blazer?Im having sum major hesitation/bogging when jumping on the gas like it would if say you were running out of gas,but could this also be caused by no ks sensor to advance timing?

About the only advice I could give is to machine a bracket that could be bolted on using the standard M6 (I think) bolt and allow the single wire KS to be threaded into it.

It could be done with bar-stock, a drill press, and some creatively precise drilling. An allen head bolt could be used to bolt this piece down. The attached image shows what it would look like for a 1/4" NPT thread & M6x1.00 socket headed cap screw (10mm diameter, 6mm tall head) - the image only shows one side of the part in cross-section. I am not certain what the size of either of the threads are so it will have to be adjusted for these pertinent details.

You dont think using a brass downsize fitting would be eter than a bracket?Also the guys at s10 forums are saying yes you can just one lead needs grounded,.Still looking for specs on these 2 knock sensor's,want to find out the output of each sensor then i can really make a decision.

A quick search for "knock+sensor+wire" with an author of "swartlkk" and CLICK HERE for a run down of the differences between the two. You could try to see if the 2-wire flat response sensor would work...

basically what i was looking for thanks man,.guess im gonna go the fitting's route.