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1995 Sedan De Ville (4.9 L)
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Discussion Starter #1
I have put a question at wrong thread... I am reposting it as a new thread:

This is my original question:
100 said:
A simple question to anybody who knows HT4100...
Does a HT4100 have a knock sensor? I thought I saw a thing looked like a knock sensor on a HT4100 I used own. But I am not sure if it was indeed a knock sensor... If there is none, that's fine, but if there is, I would also wonder why there isn't a knock sensor on 4.9...
I got a reply from peteski:
peteski said:
No, knock sensors are only installed on Northstar engines.
Why there isn't one? I guess it is because knock sensors are newer technology which wasn't incorporated into the older HT engines. It is not just knock sensor - the entire computer (ECM or PCM) is totally redesigned.


Peteski
Now, I don't own my 83 Eldorado (well, the previous owner said it was 82, but somewhere else, I saw something that gave me an impression that the car was made on 83, I am not sure...) any more, but if my memory serves me right, I think there was a little thing that looks like a knock sensor on the right side and rear side of the engine. What was that...??? I was talking to my friend who doesn't know anything about Cadillac. He thought most fuel injecton cars have a knock sensor. Since I thought there was a knock sensor on a HT4100 (at least in 82 or 83 Eldorado), a 4.9 (I don't know 4.5) seemed to be an anomaly. That's why I am asking this question...

Thanks to help geting rid of a little "?" in my head...
 

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85 Eldo Biarritz
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Thanks for reposting.

I currently have 84 and 85 Eldorados in my driveway. Both with HT4100 engine. I also have Factory Service Manuals (HELM) for both years. Neither car (or the manual) mention a knock sensor of any kind. Hopefully someone else will chime in here and confirm what I already know. :)
Also, my 93 Eldorado with a Northstar engine (also in my drivaway) has a knock sensor which is currently telling its PCM that I'm using 87 octane fuel in it. :D

Hey 100, if you were to give us details of where exactly is the item which you think is a knock sensor (and what it looks like) we could tell you what it really is.

Peteski
 

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1995 Sedan De Ville (4.9 L)
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Discussion Starter #4
Thank you again for your comments.

peteski said:
Thanks for reposting.

Hey 100, if you were to give us details of where exactly is the item which you think is a knock sensor (and what it looks like) we could tell you what it really is.

Peteski
Unfortunately, I don't own the 83 Eldorado any more. I can't post any detailslike photos... Let me try to remember as hard as possible though: The HT4100 was longitudinally mounted under the hood. On the cylinder that was on the passenger side and very end of the engine toward the firewall, there was a little thing (about an inch in diameter?) attached. I believe it had only one wire coming out. Too bad, this is all I can remember.

Anyway, also as Night Wolf said, it seems that there was no knock sensor on 4.xs. I will tell my friend that all 4.xs don't have a knock sensor. No anomaly there! But then what was what I saw in Eldorado???

Thanks again.
 

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85 Eldo Biarritz
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There is an item like one you descibe but it is on the drivers side of the engine. That is "Engine Metal Temparature" sensor. It senses the temperature of the head (not coolant). If it is too high, it lights up a warning light. It is a circular shaped sensor threaded into the side of a head. It has a single lead attached. It is a simple temperature activated switch.

Maybe that is what you're thinking of...

Peteski
 

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peteski said:
There is an item like one you descibe but it is on the drivers side of the engine. That is "Engine Metal Temparature" sensor. It senses the temperature of the head (not coolant). If it is too high, it lights up a warning light. It is a circular shaped sensor threaded into the side of a head. It has a single lead attached. It is a simple temperature activated switch.

Maybe that is what you're thinking of...

Peteski
Do the 4.9's also have this. When we were putting my 4.9 into my Fiero we noticed a few oddities and I belive this was one of them?
 

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Discussion Starter #7
Ohhhhh thanks! Mystery has been solved! You must be right about it!

I had to admit that my memory is bad... So is it on the driver side?

peteski said:
There is an item like one you descibe but it is on the drivers side of the engine. That is "Engine Metal Temparature" sensor. It senses the temperature of the head (not coolant). If it is too high, it lights up a warning light. It is a circular shaped sensor threaded into the side of a head. It has a single lead attached. It is a simple temperature activated switch.

Maybe that is what you're thinking of...

Peteski
Thanks!
 

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85 Eldo Biarritz
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That's where I saw it last time I looked... Right now both 80s Caddies are under cover and covered with snow. So, I won't be opening their hoods anytime soon.

Maybe someone with a 4.1 in a warmer climate can confirm this.

Peteski
 
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