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4.0 Thermostat housing

falconian

New member
City
Sarasota
State
FL
I just installed the Sniper EFI system on my 258. The problem is that I‘m using the temp port near the firewall for my temp gauge and don’t see another available port. i’ve looked everywhere. i need a 3/8” port for either the EFI or the temp gauge.

I’ve searched the forums and see reference to a 4.0 thermostat housing, but i can only find ones with an additional hose connection and not a threaded port. does anyone have a part number for a thermostat housing with a threaded port?

Thanks
Craig
 

CJ-8_Jim

Scrambler Junkie
Lifetime Member
City
NW Chicago Suburb
State
IL
I thought all YJ 94-95 4.0 T-housing have a temp port that is used for the MPI. It's not 3/8, but maybe the YJ resistant/ohms matches yours. In that case you could get a corresponding pig tail and splice into it a yj

As I think about it, an easier option would be IF there is a brass reducer fitting you could find from the plumbing section of your favorite big box home improvement store.
 
Last edited:

Rosco1974

Scrambler Junkie
BENEFACTOR
Gold Member
Lifetime Member
City
Oklahoma City
State
OK
What about this port (if your manifold has it)? IIRC this is the temp sensor port for the BBD/Emissions computer.

Screenshot_20200510-234742_Chrome.jpg
 

tower210

Scrambler Junkie
Lifetime Member
City
Olathe
State
KS
I don’t remember which one I have...pretty sure it’s the stock 94 xj 4.0 housing

8C9B98EB-FFF4-492E-9816-FFAE1DF6E5D3.jpeg
 

CJ-8_Jim

Scrambler Junkie
Lifetime Member
City
NW Chicago Suburb
State
IL
I don’t remember which one I have...pretty sure it’s the stock 94 xj 4.0 housing

Yes, That's it! That is what I was thinking.

Falconian - Rock Auto is a great tool -- very user friendly lookup and cross-reference.
That T-Housing with threaded sensor port (albeit larger than 3/8") was used across many years and many models:

1589214031696.png
 

ag4ever

Average Nut
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Silver Member
Lifetime Member
SOA Member
City
Richmond
State
TX
I’m about to install one, which wire did you tap for the key on signal?
 

falconian

New member
City
Sarasota
State
FL
Ag4ever, I cheated and installed a Centech harness last winter, but I used the wire for the electric choke.
 

ag4ever

Average Nut
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Silver Member
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City
Richmond
State
TX
Thanks. I’m in the process of identifying all the under hood wires and thining out any unused harnesses. I think I have that wire available, even though this Jeep had a janky manual choke cable that belonged on a lawn mower installed by a previous owner.
 

Sfisher

Basic User
Silver Member
City
El Dorado Hills
State
CA
I don't have the parts numbers, but I wasn't able to use the port because it was too close to the bracket on for the serpentine beltIMG_1218.jpg
This pic is a little deceptive, the plug is right against the bracket to the right. Here was the alternative I chose:IMG_1219.jpg
 

tower210

Scrambler Junkie
Lifetime Member
City
Olathe
State
KS
Got it! CA 258 with 4.0 head & MPI. I had a CA 258 with the serp before my 4.0 swap
 

jmarkel

Scrambled for Life
City
Fairfax Station
State
VA
I just recently reinstalled my Howell EFI on my engine rebuild. It has two temperature sensors on it. One sits at the back of the head right at the firewall. That goes to my temp gauge. The other is the two pronged one that provides temp readings to the computer. That one is threaded directly into the intake manifold. I don't see any difference where you put it, as long as it has good flow to it.
 
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