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Discussion Starter · #1 ·
My most recent dilemma is one that I do not see on my searches.

I am in process of swapping a97 Mark VIII engine into my 95 Cougar. I am using the SOHC harnesses and the Cougar PCM. So far I have had to modify connectors and wires (length) to make it fit the new engine.

Here's the rub:

The Mark engine has one temp sensor, a 2 pole device on the right upper side of the engine.

The 2v engine has three CTS.
Upper left side, 2 pole connector
Upper right side, 1 pole connector
Rear right crossover/heater core inlet tube.

I may be able to add a second sensor(1 Pole, to the large front coolant crossover tube with an adapter to get to 1/2" NPT threads.

I don't know what to do about the third CTS. I am not certain the large crossover pipe can accept the #2 CTS.

Thanks for any replies, I really appreciate them.

Rocketdog
 

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The Parts Guy
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The Mark VIII coolant crossover tube should have two ports for coolant sensors to be installed into.

The third sensor is just for the EATC. It prevents the unit from running the blower fan at full speed when heat is commanded and the coolant temp is low. If you really want to retain it, it can go anywhere on the feed to the heater core.
 

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Discussion Starter · #3 ·
I am going take a photo and post it for you because I am a bit off your page here.

The 2 wire sensor is threaded into the Intake, and the crossover has just one port (unscrews with 1/4 drive square tool.

Thanks
RD
 

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1994 Cougar XR7 DOHC/5-Speed
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The ports on the DOHC crossover are near the head flange, the one you are referring to is the fill/burp plug for when you change coolant. The 1 wire sensor from the Cougar simply uses the body of the sensor to ground through the engine where the other sensor uses a separate ground wire(signal return) off the connector
 

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Discussion Starter · #5 ·
Yup, you are right, the 2 pole is in the crossover on the right at the bottom. I assume I can put the second sensor in the port on the right at the top of the crossover.
The plug in mine has an O ring on it, so I am not certain about using an adapter and the old sensor with 1/2 NPT threads.
Is there a 1 pole sensor available with the proper thread and an O ring for that location?

Thanks for the patience and the extra help.

RD
 

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The Parts Guy
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Ports are on either side of the crossover tube as shown here (this photo was taken to illustrate the method for careful removal of the tube from the heads by prying upward at the coolant sensor boss on each side).
44525
 

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Discussion Starter · #8 ·
Ok, now I think I understand, but let's see.

The top port is for filling, burping the system, not for a sensor location.

The two pole sensor on the right (passenger) side base of the crossover is for the PCM.

And, there is a second sensor port on the crossover tube on the left (driver) side base?

I removed the crossover tube, cleaned it up with a wire wheel, painted it, put new O rings in it and installed it with the freshly cleaned intake and IMRCs with all new gaskets.

I must be getting old because not only did I not remember the sensor mounted on the right, I totally missed the port on the left.

Incidentally, gently prying the tube out is not how it went at all. That thing would not budge even with penetrating oil soaked in for days and several attempts to gently pry on it.

I ended up confronting the stubborn plumbing with increasing violence, and finally pounded the thing up and out with a block of wood and a mid size sledge hammer.

The part was reluctant to be re-installed until I got the right O rings on it. 3 tries got me from a 216 to a 213 size, and it popped in with a satisfying and firm thunk.

Thanks for the help, tomorrow I will check it out again, and wear my glasses this Time.

RD
 

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One difference in sensors I do k now about is the oil pressure sw; one is closed good, one open is good. None have a real sender unless added; there's a resistor setting a reading of oil pressure.
 
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Discussion Starter · #10 ·
As I understand it, the oil pressure gauge indicates when pressure rises above 7lbs psi. There is no resistor in the circuit to further define the amount of pressure, so the guage is really just an idiot light.

One wish I have is to indicate trans and engine oil temp and pressure to the operator. That idiot light/guage is pretty pathetic.

Thank you for your input.

RD
 

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As I understand it, the oil pressure gauge indicates when pressure rises above 7lbs psi. There is no resistor in the circuit to further define the amount of pressure, so the guage is really just an idiot light.

One wish I have is to indicate trans and engine oil temp and pressure to the operator. That idiot light/guage is pretty pathetic.

Thank you for your input.

RD
The resistor is to set where the needle goes to when the switch closes.

Otherwise, it'd peg.

And the resistor is normally on the instrument cluster flex PCB.

RwP
 
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Discussion Starter · #12 ·
I stand corrected on the resistor, there is one and it makes the needle move to center of range, see above.

And it is no more than an idiot light either way.

RD
 

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You can swap the sensor for a real sender,short the resistor,and have a real gauge.
Lazarus has this mod.
Note that tne mn12 and fn10 oil pressure switches are opposite; one shorts on pressure, one opens on pressure.
 
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Discussion Starter · #14 ·
Thanks, I put that mod on the to do list and got rid of it on the need to buy list. It will be nice to have the guage in the proper location.

I did not know the oil pressure switches are reversed.bwhat is the simple cheap and easy solution for that?

If you have a set of valve covers for a 96 or younger DOHC and they are spark plugs wire compatible, I have been advisedI need a set. Another thing I did not know is that the 97-98 valve covers are not spark plugs wire friendly. What has your experience been with plug wires on these engines?

Thanks for your help, this project continues to be a learning experience every step of the way.
RD
 

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Thanks, I put that mod on the to do list and got rid of it on the need to buy list. It will be nice to have the guage in the proper location.

I did not know the oil pressure switches are reversed.bwhat is the simple cheap and easy solution for that?

If you have a set of valve covers for a 96 or younger DOHC and they are spark plugs wire compatible, I have been advisedI need a set. Another thing I did not know is that the 97-98 valve covers are not spark plugs wire friendly. What has your experience been with plug wires on these engines?

Thanks for your help, this project continues to be a learning experience every step of the way.
RD
My oil pressure sender started leaking oil out of it a couple of years ago, and I 'temporarily' put one out of a grand marquis engine that was here in it, and it did the same thing.
If you have oil pressure the oil light is on, if you lose oil pressure, the light goes out.
I bought the correct one to install when I finally get my engine together.
So if no strangers drive your car, your light will just be on all the time, just like your 'door ajar' light probably is.
 

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1994 Cougar XR7 DOHC/5-Speed
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On Marks they use an idiot light, so the circuit has to close to complete the circuit to trigger the light, ergo with oil pressure the circuit needs to remain open. With the “gauge” in your Cougar the gauge needs power to move the needle so the circuit needs to be closed with oil pressure and only open without oil pressure(or under 7psi IIRC)
 

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Discussion Starter · #18 ·
I look forward to the news on the valve covers, thanks for looking.

I re-checked my crossover tube, and I do not have a second home for a sending unit, only the one port on the passenger side and the fill/burp port on top. I am not concerned with the third sending unit the Cougar had for the blower. I will take a picture so you can believe me this time.

My door ajar light is not on unless the door is open...so far.

I have finished the engine wire harness alterations and am leaving it unwrapped until we have a running engine. If it looks funny in pictures, that is one reason for it.

I picked up an oil pan gasket so today I will pull the pan off, clean and inspect what I can and seal it back up (including the dip stick O ring).

After that I can make and execute a punch list for getting the car ready for the new engine.

Thanks for your time,
RD
 

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BTW, the mark valvecovers respond well to soda blasting;Mine soaked up paint, snd look great.
 

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The Parts Guy
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I was able to get by the old shop today and look. I do indeed have a pair of valve covers from a '93 Mark VIII engine over there. Send me a PM with your zip code, and I'll get you shipped prices for everything.
 
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