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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I have a Pontiac 1988 - 305 motor and a Pontiac 1992 4L60 (non E) trans in a transplant vehicle (68 C10) and it has a small size (golfball size) sensor of some kind on the side of motor (not sure which side at the moment) no wires hooked up just sitting there doing nothing.
Went on RockAutos site looked up 1988 Pontiac Firebird 305 looked at the Knock Sensor and thinking the old one looks pretty much the same - not real sure as it's been quite some time I seen it.
Can anyone tell me where a/the knock Sensors location is on/in which side of block if at all its a knock sensor or somethingelse?
Last edited by mjgord51; Jan 22, 2026 at 07:35 PM.
My '88 T/A with TBI 305 has the knock sensor on the passenger side of the block, just above the pan rail.
Is that a clan Gordon avatar you have there?
Yes last name is Gordon.
I'll go outside and take a picture of it, as the ones shown on RockAuto site looks a little different as mine i think has a metal tube coming out of it and its bent over IIRC. PICTURE COMING SOON.
I must have taken it out years ago, but I did save it. - pictures below. Also this other part thinking it was just above the oil filter I also took out thinking it is a water temperature sending unit or oil sending unit - yes or no.
Last edited by mjgord51; Jan 22, 2026 at 12:21 PM.
I must have taken it out years ago, but I did save it. - pictures below. Also this other part thinking it was just above the oil filter I also took out thinking it is a water temperature sending unit or oil sending unit - yes or no.
Sorry had to Edit it for more info. Look back read again.
Thanks to all that responded back.
For the second part in top picture I've looked in RockAuto and used 1988 Pontiac 305 specks found there oil pressure sending switch shows a two pin part, this one of mine has 3 pins, and doesn't surprise me for some miss matched parts on my truck, I have came to the conclusion that PO or past owners have " Thoroughly Molested " this truck of mine using parts wise what ever they found that fit.
Here's where the knock sensor was located on block.
Yup, same as everybody else's; in the pass side water jacket drain hole.
What would it hook up on/to ? I'm not using a ECM of any type.
As said, it won't hook to anything. At this point in its life it's just a funky-shaped drain plug.
If this is that same motor you're wasting your time "looking up codes" on, you don't need it at all. An Edelbrock carb and all that, doesn't use it, as you already know. You can do away with it and put in a regular hardware-store pipe plug if you want. ¼" NPT is the size. I strongly recommend brass rather than steel or aluminum. If you ever want to completely drain the coolant out of it, you'll have to remove it then anyway, as well as the one on the driver's side. Be aware that the hole behind it often gets crudded over with rust and scale, so you might need to take a piece of a muffler bracket and rod it out; at which point about a gallon of coolant will come splooshing out, so be ready for that.
past owners have " Thoroughly Molested " this truck of mine using parts wise what ever they found that fit.
Which is why "codes" are SO UTTERLY COMPLETELY USELESS in this situation and others like it.
In a 68 truck you need a 1-wire oil pressure sending unit. Won't look anything like those others. I know this is gonna sound hard to believe, butt I'd suggest getting the one for a 68 truck instead of any 88 (or 89, which is the year that the ENGINE that your July 88 casting would have been installed into, NOT 88) application. You'll need to tell the parts store guy whether it has a gauge or just an idiot light. Either SU bolts right in. The truck should have a wire for it; should be tan or brown if memory serves, with a big round rubber boot on the end, if that has survived all these years. The place it goes in the old truck setup is behind the distributor, on top of the block, just behind the intake; not down on the side like the newer application. The port above the oil filter just gets a plug, also ¼" NPT IIRC, butt since you have the thing that came out, you can take it to the hardware store and match it up.
The temp gauge sending unit goes in the driver's side head between the #1 & #3 spark plugs. For that one, the 68 truck part won't fit, because it's ½" pipe. Get the one for about a 84 car or truck, which will have 3/8" pipe threads. They changed to that size (smaller) in about 73 or so, so that one will fit your 82 - 86 416 casting heads. Again, there's one for a gauge and one for idiot light, be sure to get the right type for whatever is in your dash. The wire in the truck for it will be dk grn.
The same hole in the pass side head, between #6 & #8 plugs, may have previously had a temp switch for electric radiator fan in it. You don't need that so just put a brass 3/8" NPT plug in it. You may also find that Skillet put a head with a plug already in it on the driver's side and a head with an open hole on the pass side; if so, you could either try to get the plug out (they are VERY ornery at best), or just swap the heads to the other sides.
Yup, same as everybody else's; in the pass side water jacket drain hole.
As said, it won't hook to anything. At this point in its life it's just a funky-shaped drain plug.
If this is that same motor you're wasting your time "looking up codes" on, you don't need it at all. An Edelbrock carb and all that, doesn't use it, as you already know. You can do away with it and put in a regular hardware-store pipe plug if you want. ¼" NPT is the size. I strongly recommend brass rather than steel or aluminum. If you ever want to completely drain the coolant out of it, you'll have to remove it then anyway, as well as the one on the driver's side. Be aware that the hole behind it often gets crudded over with rust and scale, so you might need to take a piece of a muffler bracket and rod it out; at which point about a gallon of coolant will come splooshing out, so be ready for that.
Which is why "codes" are SO UTTERLY COMPLETELY USELESS in this situation and others like it.
In a 68 truck you need a 1-wire oil pressure sending unit. Won't look anything like those others. I know this is gonna sound hard to believe, butt I'd suggest getting the one for a 68 truck instead of any 88 (or 89, which is the year that the ENGINE that your July 88 casting would have been installed into, NOT 88) application. You'll need to tell the parts store guy whether it has a gauge or just an idiot light. Either SU bolts right in. The truck should have a wire for it; should be tan or brown if memory serves, with a big round rubber boot on the end, if that has survived all these years. The place it goes in the old truck setup is behind the distributor, on top of the block, just behind the intake; not down on the side like the newer application. The port above the oil filter just gets a plug, also ¼" NPT IIRC, butt since you have the thing that came out, you can take it to the hardware store and match it up.
Here's my motto I live with when I ask a question it's because I'm after a certain answer - what ever the reason I'm asking it doesn't give you the right to belittle me just because I have a 305 ci motor so F'en what ! IF ITS NOT BROKE WHY CHANGE IT !
My other post did not say I have a Edelbrock carb like you think I have, it's a Holley and the intake is Edelbrock. There you go again Jumping to Conclusions my truck has Gauges and doesn't have a wire for a OPS.
Did you ever stop to think I might be asking the questions I'm asking because I might be thinking of going back the way it was when it rolled off the assembly line in its ORIGINAL CONFIGURATION ! ! ! No You Didn't, your mistake.
Sorry everybody for my little rant it's just that a bullie needs to be put in his place even if it's on an Open Forum.
one more thought - - - I thought people came to forums to get and give information and Not feel like they are being laughed at just because they own a Non Popular cubic inch motor or does the newbies have to develop Thick Skin? It doesn't matter what someone has big or smaller motors all at one point will need some work too them and if someone ask a question but not necessarily in a Correct way they get laughed at - That's Pathetic !
Last edited by mjgord51; Jan 29, 2026 at 11:30 PM.
Not sure what brought this on? Sure, may I feel sorry for you on account of that, butt I didn't even mention it.
it's a Holley and the intake is Edelbrock
Dreadfully sorry about that. AS IF that changes the situation at hand in any meaningful way.
my truck has Gauges and doesn't have a wire for a OPS
Well that SUCKS; kinda hard to make a gauge work when some PO "improved" it by removing the wire. If there's a gauge in the dash then there WAS AT ONE TIME at least, a wire for it. Butt if you can find it or replace it, you'll need the SUs for gauges rather than idiot lights, then.
I might be thinking of going back the way it was when it rolled off the assembly line in its ORIGINAL CONFIGURATION ! ! !
You might have mentioned that if indeed it's true. In which case, I'd have told you to yank the 89 305 and all that Holley this and Edelbrock that, and throw it in the trash, and get a 1968 something or other. You haven't mentioned what the truck originally came with so I can't even advise you on what that might be. Most likely a 230 or 250 6-cyl, or a 283 or 327 V8. Meanwhile, I DID tell you how to put it back to its "original configuration" in the areas you asked about (the KS you don't need, and the 2 gauge sending units), to the extent possible while leaving the later model motor in it; I even told you which sending units to buy and where they go. Not sure how that constitutes you "getting laughed at".
I'm terribly sorry if detailing what sending units to use and where they go, made you get sand all up in your vagina. Seems to be a common problem on forums generally so I'm not surprised in an overall general way. I'll let you go figure all the rest of it out yourself since you don't want any help. A 68 truck doesn't belong on a 82-92 Camaro/Firebird forum anyway, so technically, you're not welcome here to begin with. Forgive me for trying to be helpful in spite of you breaking the forum rules.
Not sure what brought this on? Sure, may I feel sorry for you on account of that, butt I didn't even mention it.
Dreadfully sorry about that. AS IF that changes the situation at hand in any meaningful way.
Well that SUCKS; kinda hard to make a gauge work when some PO "improved" it by removing the wire. If there's a gauge in the dash then there WAS AT ONE TIME at least, a wire for it. Butt if you can find it or replace it, you'll need the SUs for gauges rather than idiot lights, then.
You might have mentioned that if indeed it's true. In which case, I'd have told you to yank the 89 305 and all that Holley this and Edelbrock that, and throw it in the trash, and get a 1968 something or other. You haven't mentioned what the truck originally came with so I can't even advise you on what that might be. Most likely a 230 or 250 6-cyl, or a 283 or 327 V8. Meanwhile, I DID tell you how to put it back to its "original configuration" in the areas you asked about (the KS you don't need, and the 2 gauge sending units), to the extent possible while leaving the later model motor in it; I even told you which sending units to buy and where they go. Not sure how that constitutes you "getting laughed at".
I'm terribly sorry if detailing what sending units to use and where they go, made you get sand all up in your vagina. Seems to be a common problem on forums generally so I'm not surprised in an overall general way. I'll let you go figure all the rest of it out yourself since you don't want any help. A 68 truck doesn't belong on a 82-92 Camaro/Firebird forum anyway, so technically, you're not welcome here to begin with. Forgive me for trying to be helpful in spite of you breaking the forum rules.
Have a nice day!!
Seams as your the only one thats PRETTY BUTT HURT for my questions even though in my VERY FIRST POST i gave information on what the ORIGINAL 305 CAME IN - 3rd gen Firebird.
And for the belittling where that came from go back to post #12, i took it as a Slap In The Face.
I was just wanting to know what & how was a 1988 305 3rd Gen F bodied motor was configured and then you came along and posted I should trash can everything as I'm just wasting my time with what I have .
If your ONLY advice is to jump in with " your wasting your time " next time you run into someone asking similar questions - Move On and shut your Verbal Diarrhea Mouth nobody wants to here that type of Help.
Thanks for the few that did give some Positive feedback.
Maybe I'm Old School but I was always taught to ask questions if you expect an answer.
I was always taught that the only stupid question is the one not asked. Life has taught me that might only be 95% true... I've met some incredibly ignorant people at work, lol.
