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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
That head doesn't have the rear mounted sensor. I have a "Clearwater" aftermarket 0331 head that DOES have both, but the original 0331 AND the "TUPY" 0331 do not as far as I know. My original 2000 WJ did not. As I stated previously, you can mount your normal temp sensor anywhere in the coolant flow, but is best before the thermostat. Because the pipe hole for the forward sensor is larger than your original one, you'll have to use a pipe thread reducer to install it, then extend the wire to it.
You should clean the head in that area well to make sure you don't have a pipe plug in that location. It's entirely possible it's there and painted over. It was on my "Clearwater" head and I didn't notice it until it started leaking 2 days after I installed it! I totally freaked out thinking the new head was cracked!
So did you recently change the head or have you had the 0331 while the temp gauge was working?
If you didn't replace the head and had a functional gauge, then the sending unit has ALREADY been relocated. If you have the wire for the temp sending unit and the head is aftermarket (which would be a very GOOD thing since the OEM 0331's have that little cracking issue) then it could be that the plastic plug disintegrated and you may not be seeing the tiny little sending unit in the head (or mistaking it for a bolt).
When I did the gauge swap on my 95 I went to pull the connector off the old sending unit and the thing literally fell apart in my hand. The sending unit is pretty freaking small, IIRC it was like a 14 or 15mm deep socket to completely remove the sender, so the middle part of it (including the plastic wiring connector ) is no more than 11mm diameter.
So I actually just bought this 1990 cherokee last spring, and I'm pretty new to this whole off road game. I'm still learning everything, and of course the guy I bought it from neglected to tell me that the head had been replaced with the 0331. The guage was working properly when I bought the thing, so it has surely been relocated somewhere and I just dont know where. I'm curious now if there was an entire engine swap done. How would I go about figuring that out?
So I actually just bought this 1990 cherokee last spring, and I'm pretty new to this whole off road game. I'm still learning everything, and of course the guy I bought it from neglected to tell me that the head had been replaced with the 0331. The guage was working properly when I bought the thing, so it has surely been relocated somewhere and I just dont know where. I'm curious now if there was an entire engine swap done. How would I go about figuring that out?
If it has a distributor then it's NOT a 00-01 engine. Does it have a distributor?
There are casting marks on the block. Almost certainly it was just a head replacement.
Yes and I can see the coil rail mounting boss so it is an 0331 head. NOW, take off the oil filler cap and look down the hole with a flashlight. Hopefully, you will see a "TUPY" cast into the metal like in this picture. This shows it's a 2002 or newer 0331 head which was recast to not crack. If you don't see the marking, it's an earlier 99-01 0331 head that has a history of cracking. Also notice the 0331 marking in the upper left corner of the picture. It could also be an aftermarket head without those markings.
Yes and I can see the coil rail mounting boss so it is an 0331 head. NOW, take off the oil filler cap and look down the hole with a flashlight. Hopefully, you will see a "TUPY" cast into the metal like in this picture. This shows it's a 2002 or newer 0331 head which was recast to not crack. If you don't see the marking, it's an earlier 99-01 0331 head that has a history of cracking. Also notice the 0331 marking in the upper left corner of the picture. It could also be an aftermarket head without those markings.
I will check. Just got a bit busy so I'll get back to you later. Greatly appreciate the help
And there it is on side of the t hsg. Also looks like you are missing some oil leaks looks like a pretty dang clean motor!
haha it wasnt when I bought it. I replaced the valve cover gasket first thing and it hasn't leaked yet.
so the sensor on the side of the housing is the only one that Matters on the 0331? So that means when the head was replaced, the person just didnt remove the old single wire for the rear sender that no longer exists... is that right?
haha it wasnt when I bought it. I replaced the valve cover gasket first thing and it hasn't leaked yet.
so the sensor on the side of the housing is the only one that Matters on the 0331? So that means when the head was replaced, the person just didnt remove the old single wire for the rear sender that no longer exists... is that right?
I don't know if the threads size are same old verses new but if yours still have 1 wire (pics looks like one wire but really cannot tell) maybe if threads are same and you still have a single wire maybe they just extended it?
I don't know if the threads size are same old verses new but if yours still have 1 wire (pics looks like one wire but really cannot tell) maybe if threads are same and you still have a single wire maybe they just extended it?
there are 2 wires coming from the sensor into a 2 prong plug... this is why I think the single wire with the L shape connector is now obsolete. It was used on the original head, but since the 0331 doesn't have the rear sender, it must not be necessary. I did happen upon the wire dangling under the truck when I was replacing my CPS
Okay we've got a couple of things working here. The single wire sensor is hooked directly to the gauge on a shunt circuit where any change in resistance causes the needle to deflect. The 2-wire sensor sends a voltage signal to the PCM where it is interpreted and the PCM sends a signal to the gauge for needle position. 2 totally different systems. The 2 sensors are different pipe thread sizes but you can use a reducing bushing to mount the small sensor in the big hole. IDK how he got your gauge to work with the 2 wire sensor anyway. I think the small sensor uses it's case as the ground and the large 2-wire sensor uses one pin as a 5v supply and the other as the signal return.
The reason the later temp sensor is hooked into the PCM is because the newer data bus system uses information from many different sensors to set mixtures and spark advance depending on whatever the engine is seeing for operating demands. You can thank the EPA for tighter emission standards for that.
Okay we've got a couple of things working here. The single wire sensor is hooked directly to the gauge on a shunt circuit where any change in resistance causes the needle to deflect. The 2-wire sensor sends a voltage signal to the PCM where it is interpreted and the PCM sends a signal to the gauge for needle position. 2 totally different systems. The 2 sensors are different pipe thread sizes but you can use a reducing bushing to mount the small sensor in the big hole. IDK how he got your gauge to work with the 2 wire sensor anyway.
I really wish I understood electrical stuff haha. So you're saying that I do need the single wire with the L shaped connector still, as well as the sensor that's in the t-stat housing?
09-28-2018, 01:12 PM
