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post #1 of (permalink) Old 07-20-2009, 05:16 PM Thread Starter
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Oil Pressure and Temp Guage on CJ8

So I am slowly trying to fix all the little things on my recently acquired '81 CJ8 Scrambler w/258. On the punch list is a non-functioning temp gauge (or sender) and a similar problem on the oil pressure. I do have a copy of the troubleshooting CJ guages document so I am somewhat familiar with testing procedures. My trouble is before I even get a meter reading.

When I looked at the water temp sensor location (drivers side back/top of block near firewall right?) I find a square block that has two ports, one is closed off with a bolt the other has the following plugged into it

Now I have had a couple of '84 CJs and I was used to seeing a somewhat thin threaded brass/copper looking device with a single connecting post. What is pictured above looks like an oil pressure switch. There are two red wires connected to the sensor via a plug but at the guage side there is the single purple wire as I am accustomed to.

Anyone have any ideas as to why this would be here? Is that a temp sensor? Why two wires, the purple sensor wire with the 90 degree connection bootie is right next to it un connected.

Even more confusing is that when I look at the oil pressure sensor I see a bell shaped unit with a single post on it. Are both these sensors the wrong ones. I get a low ohm reading from the oil pressure sensor (right off the post) of about 24 ohms. This appears to be way out of range.

I will try to post a pic of the engine compartment later on today.

Thanks for any comments on this.

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Last edited by relsner; 07-20-2009 at 05:21 PM. Reason: pic
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post #2 of (permalink) Old 07-20-2009, 11:03 PM
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Originally Posted by relsner View Post
Anyone have any ideas as to why this would be here? Is that a temp sensor? Why two wires, the purple sensor wire with the 90 degree connection bootie is right next to it un connected.
It sounds like itís the oil pressure switch for the electric choke.

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Those who understand binary and those who don't.
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post #3 of (permalink) Old 04-17-2010, 12:39 AM
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On the temp gauge, it seems they are using a plumbing fitting to attach more than one sender. Maybe they had an aftermarket gauge running at the same time as the stock gauge?

On the oil pressure, my 83 Scrambler had a plumbing fitting allowing two senders. One of them is the bell-shaped 1-wire. The other is a 2-wire. I believe the 1-wire feeds the stock oil pressure gauge. I think the 2-wire is a safety shut-off switch, if oil pressure goes to low it kills the ignition. Not totally sure about that though. If you go to the parts house and ask for the oil pressure sender, let us know if it's the 1-wire or the 2-wire!
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post #4 of (permalink) Old 04-17-2010, 06:02 AM
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i think you are looking at something else...i realize my 258 is a bit older, but dont see a reason they would've changed location...my temp sender is directly under the thermostat on the front of engine, single wire attaches (well...used to when it was there) similar to a sparkplug (just pushes onto post)...if your gauges are the same as mine, check the wiring on back speedo cluster to make sure nobody boogered it up...search john stenks' gauge page (ill post link when i get online from the house) its a very detailed writeup on this subject

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