Changed the title again for more hits.
Read the last couple of posts on what I figured out. If you bought the painless kit to run the stock efi on a magnum 360, which would you rather do to get it to work.

Okay, while working on the car last night, I realized there might be a problem.

Painless put a water temp sensor in this stand pipe.
This is for a heater hose and goes to the heater core.
Now all the mopars I have ever owned shut the water off completely to the heater core unless you are running heat. Which I do not plan on doing.
So if I am thinking this through properly, that will never read acurate coolant temps.

Where else can you put this sensor?

here is a sensor in the intake. Has a grey plastic body.
Anyone know what it is for?

nevermind about the grey sensor. Found out it is the air temp for sure.

Still need ideas on where to mount the other sensor though.
Somewhere in the mag motor that has coolant flow all the time.
I also thought about the bypass hose, but it is in such a bad place under all the mounting stuff I can't see using it.

Has to be something simple so anyone who does this swap can do it.

Worst case is to enlarge the original sensor hole and tap it to put it there, but I can't imagine anyone wanting to do that if they bought a plug and play efi kit.

I've seen lots of applications (think 80's smog vacuum hose spaghetti) that put a TCS in the upper radiator hose neck (aka thermostat housing).

One hole in the housing tapped with pipe threads. Heck, some of those housings are almost universal when it comes to footprint on the bottom and hose size of the neck.

found a chevy housing spacer with taps in it. I will look to see if there is enough room to put a sensor down there since it is tucked away so far.
Thanks for the idea.

Do the heater hoses need to be connected for the coolant to circulate properly? If not, why not just pull the standpipe and put the sensor in that hole? On my M1 manifold, the CTS is under the A/C compressor. Not convenient, but how often do you have to replace a CTS? There's a hole in the A/C compressor bracket, but I don't know what that's for since I don't have a full factory setup on my Valiant and the CTS doesn't line up with it on the M1.

Why not run heat? The CAA underdash unit should be set up for it, and you KNOW you're going to want to drive that Vert on a nice December day...

Clair

The pipe is in the hole for the heater hose from the pump. They put that t in so they could put in a temp sensor.

As for heat, sure in Dec, but not on a day like today.

So here are my two options so far.
They make a spacer that bolts up at the thermostat housing and has two holes set up for sensors. That runs anywhere from 25-37 bucks.

The second choice is to run a couple of t splices into the heater hose and have the t run offs at say 1/4 inch or smaller so there is some flow for the sensor. I don't expect this to run much more than 15 bucks. But that also means having that pipe and t section added to put in the sensor.

If you had to do one of these for the conversion to keep the efi, which would you do?

Is there not a hole on the other side of the thermostat housing? see pic intake is off a 99 ram and the same for my 95.

That sensor is still in place. They are using gm style sensors that are at least 1/4inch, but I think they are 1/2inch npt that do not fit in that hole.

The have asked if I was willing to drill and tap the hole for the sensor, but I don't think that is a good idea for a conversion plug and play kit.
A lot of people won't have that ablity. Plus I don't want to have to buy new gaskets and bolts.

But if I can't find a better solution, then that will be what I have to do.

use a adapter 1/8 1/4?? to 1/2 npt fitting to up the size to what you need and cap the other one off tell you need heat.

looks like they want it in the intake. So I will have to drill it out after all.

Will their sensor pigtail not physically plug in to the Mopar/Magnum temp sensor? They (or you) should check some of the earlier model sensors, as I think some of the connectors changed over the years, particularly between the OBD-I and OBD-II years. I know this is true about the TPS and MAP sensors, or at least that's been my experience hooking all the various parts up to my Frankinjection system on the Valiant.

If nothing else, Painless should supply the sensor ends to work with the Mopar sensors that are native to the engine. I mean, they sell WIRING HARNESSES, they can make this happen. Sensor output should be identical, so I doubt that's going to be an issue. I'm not bashing Painless at all, but let's take a look at the product they're trying to make, the engine it's going to be hooked up to, and the folks that they want to buy it. Use the stock Magnum sensors...

Clair

They are using gm style sensors everywhere.
I guess I can ask.

their response was that the analog ranges are different, so they are using the gm ones for the computer.

when you tap it out go slow or it might chew the intake up. or have a shop do it for you. I have a 99 intake that i can send you if needed.

Good luck

Thanks.
I am going to try it without pulling the intake.
I will pull the thermostat housing and get something under where I plan on putting the hole to get the chips so I don't have to flush it out.

use some grease too, it will hold the chips.

and the npt taps are tappered so dont go to far or you will have a loose hole

Thanks for that tip. Didn't think about that, so I would have threaded it all the way through.

The CTS sensor response is definitely different between Mopar and GM (see www.msefi.com for the exact response curves of each). My CTS is a GM one (with the single blade connector sticking out) that cost about $0.50 at a local junkyard. It fits in a perfect sized hole in my M1 intake directly under the A/C bracket. I simply bent the blade in the direction of where I needed to plug in the CTS signal wire connector. BTW I fabbed up the harness and computer (MegaSquirt) by hand in a few hours so if this redneck can do it w/junkyard parts then surely someone armed w/the power of "Painless Wiring" can do it...