8 cylinder front engine iconic vehicle
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By linderpat
#171823
Intermittent oil gauge. Sometimes it works, and is fine, and sometimes it drops o zero and stays here. Is my sender going bad?

85 5 speed. Lots of work done, car is in good shape overall.
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By Zirconocene
#171824
How's the wiring? Mine was pretty crispy and needed some new insulation.

Cheers
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By worf
#171828
linderpat wrote: Mon Sep 19, 2022 12:05 pm Intermittent oil gauge. Sometimes it works, and is fine, and sometimes it drops o zero and stays here.
Is my sender going bad?
Unlikely. More likely…

Zirconocene wrote: Mon Sep 19, 2022 12:06 pm How's the wiring? Mine was pretty crispy and needed some new insulation.
… wiring, or solder joints, or cluster connectors.

If I were to attempt to solve this problem by throwing parts at it, rather than diagnosis, the first part would be a new front main harness (starter,alternator,jump post.)

Diagnosis would start with a multimeter at the jump post connector pin for the sender or the fuse panel connector pin for the sender.

Of the dozens of “oil pressure” problems I’ve solved over the years, only one was through sender replacement.
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By linderpat
#172066
luckily, my car is a fairly low mileage car that lived most of its life in the Northeast, garaged mostly and put away winters, and the plastic and wiring is still supple. I do think it could be pod related. I'll pull that and make sure the connection is good. I did a pod refresh a year ago and all was fine back there. but the oil gauge issue is a new one. I'll check the connections underneath too, before the pod.

Using the multimeter at the jump post, which pin is it? Also, which fuse panel slot for the sender?
TIA.
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By worf
#172440
Will you be at Frenzy?
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By worf
#173151
linderpat wrote: Wed Sep 21, 2022 5:15 am Using the multimeter at the jump post, which pin is it? Also, which fuse panel slot for the sender?
To your question: Pin 4 on the jump post connector is for the OP Gauge. It is a resistance circuit to the cluster. Ground is the sender connection to the block. No fuse.

In my experience, wonky, wobbly, jumpy OP is always front main engine harness wiring at the sender. Any past service of alternator or pan gasket results in a non-zero probability that a not-careful or trying-to-do-the-job-as-fast-as-possible "technician" damaged the wiring at the sender. Also, oil pan gasket leaks result in that part of the harness soaking up oil which, over the years, will damage the conductor insulation.

Start there. Under the car. At the sender. Very carefully pull back the boots on the sender connection and examine the wiring to the sender. Gauge wire is blue with a white strip. Idiot light wire is blue with a black stripe. Those colors would have faded towards "motor oil" color over the years.
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By linderpat
#173555
Thanks Dave - that's where I'll start.
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By grepin
#174004
I have an oil pressure warning light that I believe I have traced to a terminal at the CE warning computer. Because when I wiggle the wire that carries that signal it goes away. I tried redoing the solder on the board and it didn't help. I am not sure if this could be your issue as mine is the warning flasher only not the pressure gauge.

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