Oil pressure and Engine temp gauges freaking out

Title says it all it started a couple days ago with just the temp gauge freaking out and I was going to buy a temp sensor/sender but last night on my way home the oil pressure gauge started dropping as well. Also when this happens the check gauges light comes on but that only started with the oil pressure freaking out.

The jeep sounds/feels/looks like it's running fine no knocking no shuddering no smoke from the engine or exhaust.

Searching the forums is telling me to check the grounds and the alternator but the alternator is only about 4 months old and the grounds all look good.

I guess it could be the pressure sender and temp sensor but it seems weird they'd both go out so close to each other though I guess it's not impossible.

Anyone have any clues or has anyone seen anything like this before

2000 XJ 4.0l auto w/8.25

Thanks!

What do you mean by freaking out? What are the gauged doing?

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Sorry a bit vague I didn't think about that.

It's generally registering it's readouts as it normally does, at idle ~7 and at merging/heavy accel speeds its ~40 but as of yesterday it will occasionally drop out entirely for a few seconds register fine for a few seconds and than drop out in about 5-10 second increments.

Two things I have found that can cause the gauge problems in my 2001 XJ.

First and most likely, the instrument gauge cluster's two plugs can loosen or develop debris on the contacts.
The dash need to be partially disassemble to get to the gauge cluster.
Once there, grab onto both sides of the cluster and pull out.
Clean the contacts and reassemble, push in and out several times to make sure the contacts are making a good connection.

Second, up under the dash, driver's side, far left, is a big plug with a couple dozen wires passing through. The plug is bolted together and can loosen or the contacts get dirty.
Try loosening the plug, pull it apart and work it in and out a bit and then screw it back together tight.
You may need to push the plug together manually, along with the using the screw, to fully seat it.
Found the same loose plug in both the 2001 XJ and my 1997 Dodge Dakota.
Neither have been fully pushed together at the Factory.

Interesting, I'll give it a shot now and report back

The old-school needle gauges have a tiny coil inside near the base of the needle. Voltage passes through the coil on the way to the ground point and generates a magnetic field the pulls the needle. Variable ground produces variable current through the coil resulting in variable magnetic field, producing the sweep of the needle. If you ground the circuit direct to ground (bypass the sender) then the coil gets full voltage and the needle will peg. If you disconnect the circuit (infinite resistance) then the coil gets no voltage and the needle will peg in the other direction.

Most likely, you have a bad ground

Most likely, you have a bad ground

Click to expand...

This or a bad connection to the sensors but since it's multiple gauges, I'd go with a shared ground

reseating the cluster seems to have fixed the issue with the temperature (seems to)

the oil however I found it registers once the revs are over about 3k but before that it doesn't register

ehall said:

The old-school needle gauges have a tiny coil inside near the base of the needle. Voltage passes through the coil on the way to the ground point and generates a magnetic field the pulls the needle. Variable ground produces variable current through the coil resulting in variable magnetic field, producing the sweep of the needle. If you ground the circuit direct to ground (bypass the sender) then the coil gets full voltage and the needle will peg. If you disconnect the circuit (infinite resistance) then the coil gets no voltage and the needle will peg in the other direction.

Most likely, you have a bad ground

Click to expand...

That makes sense ill give it a shot and see what happens there. all the other posts I searched up were saying bad battery ground. wouldn't it be a bad ground at the block in this situation as thats what's carrying the return voltage to the - on the battery? I guess it could still be battery but wouldn't more stuff be freaking out?

Oh, dear funk, I have to go through this XJ with a fine toothed comb. I went to look at the sender to test it and saw some electrical tape around the clip. grabbed it and felt loose figured maybe it wasn't plugged in all the way. Nope last owner broke it and taped it back on. Sooo here I go to find a sender. Thanks for the tips guys even though they weren't the problem =)

Can't believe someone would do that...

xCWolf said:

Oh, dear funk, I have to go through this XJ with a fine toothed comb. I went to look at the sender to test it and saw some electrical tape around the clip. grabbed it and felt loose figured maybe it wasn't plugged in all the way. Nope last owner broke it and taped it back on. Sooo here I go to find a sender. Thanks for the tips guys even though they weren't the problem =)

Can't believe someone would do that...

Click to expand...

I can. I needed to solder the wires for both my o2 sensor and temp sender for same reasons.

Hahaha yeah my po was kind of lazy of seems. My door wires were twisted and taped. Really? Ugh. I hate lazy owners.

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