1997 Mountaineer 5.0 for Coil-near-plug swap

[ATPCR]

Cat/muffler plate

01

02

Still not quite complete.

Another view.

welding.

Some of the better welding.

Cats nestled up in there.

08

Catalytic converters touching at the corners.

Welded the corners in the middle of the assembly.

11

Left o2 sensor too far back plugged.

Hole for bung.

Clamped ready to weld bung.

Left narrow band o2 sensor installed.

Hanger made from jack handle.

Recycled muffler clamp.

Hanger & clamps installed

[ATPCR]

I'm back around to the PCM harness that needs to be finished up. The 1999 Crown Vic PCM has to have a CHT signal to function properly cold and at operating temperature. I've been looking for a CHT sensor that might work in a 302 Windsor cylinder head; however, an accessory bracket hole would have to be taken over to screw a sensor in. Also, that makes me wonder where the temperatures of aluminum heads like the 4.6 Crown Vic engines run compared to the temperatures of cast iron cylinder heads do. I don't have a 4.6 Crown Vic car of any year to take some measurements. A 2001 to 2011 Ford 2.3-liter CHT sensor may can be made to fit a 3/8"-18 hole. I do have a temperature chart of the sensor resistance measurements, but I'm not sure what would be the normal readings at a "warmed up" temp or what is considered overheating as far as the PCM interrupt feature goes. If I knew, I could make a temporary circuit while I source an appropriate CHT sensor. A pair of wires could run from the CHT circuit to 2 resistors and a SPDT (on-off-on) switch with one resistor to match a cold temp like 50 degrees F and a warm running temperature of ??. Thereby giving the PCM what it wants. Flip the switch up for cold engine "choke" of a sort and flip the switch down for now the engine is at operating temp and the PCM would trim the fuel back now that the engine is warm. Maybe this would work just to make it drivable for the 4.75 mile trip from home to work and back?
Any thoughts? Partial chart below. Right hand column is resistance in K ohms.

[ATPCR]

If I could find a CHT sensor like this with Ford scaling, I could use the threaded 3/8" hole on the back of the driver's side head furthest inboard to locate a CHT sensor. I'm trying to get this worked out with the PCM that I have. Per Michael P.s recommendation, the next C-N-P 5.0 conversion that I put together will use the Ford full size sedan PCM. Thanks to ALL of you who have given me advice and information.
ADDED: I can't believe that I'm the only person checking in at this forum with an active "garage" project.
https://madracingparts.com/products/mad ... ead-sensor

[BOOSTEDEVERYTHING]

If you have a coolant temp gauge in the car you could do it like you are saying in the above post. you should be able to find the cht transfer function and just make the circuit match what operating temp is on a crown vic. should be in the service manual or online somewhere . I'll have a look and see what i can find for operating temps in the pced.

[BOOSTEDEVERYTHING]

Here are the PCED reference values for 1999 Crown Vic. And the Charts for CHT sensor

[ATPCR]

Thank you BOOSTEDEVERYTHING I may have the CHT sensor situation worked out. I have a Ford sensor on the way that has 10 mm threads. I will need to cut them down to 9.53 mm or 3/8"-16 standard. Then I have picked out a 3/8"-16 threaded hole in the back of the driver's side (US) cylinder head to install the sensor into. I will pay attention to the temperature readings during some Real Time situations. I hope that the pcm receives the temp readings that it wants.

[BOOSTEDEVERYTHING]

You have to make sure the sensor contacts the head in the correct position for it to get good metal temperature readings as well. On the new Coyote engines the CHT sensor is a one time use sensor that the tip actually gets crushed against the cylinder head to make correct contact with the metal. Also, the position in the head can be important as well. May want to be as close to a "hot spot" in a cooling jacket as possible to get accurate readings. Just some food for thought..

[ATPCR]

It is in the inboard hole on the head directly next to the cooling runner of the intake flowing into the head.I had just one 3/8"-16 hole available that I ended up installing the CHT sensor into. The other hole has a piece of broke off "christmas tree" wire loom holder in it. The engine is in the vehicle so I didn't have much working room to chase the head hole with a 3/8"-16 tap. I was forced to use a couple of washers to fill in the gap between the sensor after it bottomed out. I had it in and out a couple of times. It would not have been accessible with the upper plenum on. I hope that the washers help with the heat transfer or heat sink properly. This is an experiment. But before I installed it, I had to prepare it. it was a CHT sensor with 10mm threads. I purchased a new die to cut it properly.

[BOOSTEDEVERYTHING]

I think as long as the tip contacts the metal cleanly it should read ok. I would definitely compare it with a known good gauge and make sure the readings are at least very close before relying on it as a primary temperature sensor. I have noticed the metal temp sensors are a little finicky on the newer vehicles. Never really paid much attention on the older stuff, never really had many cooling issues from older stuff with that type of sensor. On a side note, It will actually read temperature if you ever loose coolant or have an air pocket, unlike fluid temp sensors, so that is a major plus!!!
On another side note: heat transfer relies on metal types as well, I would guess that brass washers may be better to use than steel ones for that purpose to keep the sensor and washer metal types the same. using steel washers may hinder heat transfer a bit, but I am no metallurgist. So may want to consult the all knowing Google for that one. LOL

[ATPCR]

What is your first name? The way that the 1999 Crown Vic is wired is, it only has a CHT sensor then from the PCM there is an output wire to the dash temperature gauge. I'm using the Explorer/Mountaineer harness and rearranged the pins to match up to the 99 Crown Vic PCM.
Also, the Crown Vic program is such that, if you overheat the engine, then the PCM cuts off 4 of the injectors to help cool the engine quickly.
I think that your Ranger/Explorer 5.0 temperature sending unit for your gauge is wired like mine. Mine has a one wire simple temperature sending unit attached to the traditional Ford color coded wire, red/white stripe. I won't be relying on the PCM to feed the temperature gauge, I'll be getting a wet water temp directly off of the aluminum intake.
Michael could answer this question. If the CHT temps are running a little lower because of the way that I had to rig it up, could a simple multiplier patch be added to the file to "calibrate" it to send proper data to the PCM? I may be overthinking it and it may work fine.
I don't have any brass or aluminum washers to swap out with the cheap plated steel washers. I just didn't like leaving the gap at the hex head of the sensor after it bottomed out in the head hole. The washers are the thickness of the gap so the sensor is barely touching now. I wonder if putting some anti-seize on the brass sensor threads where it is screwed in to the cast iron head would be ok?