stock Oil Psi sender needed

MadCow23

Restoring
Oct 28, 2012
34
0
0
Cincinnati
Well, you got me thinking. So I looked it up on the TSRM, and came up with this.
I have an 87 with a 7MGTE, so I might be different depending on the year / engine.

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The TSRM lists it as an input to the ECU. So I'd say it's a good idea to keep it hooked up.


Saying that, mines totally been swapped out with an aftermarket gauge. And I'm now considering reinstalling the stock sender.


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maitai69691

New Member
Jul 24, 2005
280
0
0
42
hilo hawaii
I I know the ecu gets a signal for oil pressure. Just woundering if it would affect any drive ability or cause the ecu to not run normally...or why does the ecu need to see oil psi.
 

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
If I understand your question correctly the answer is yes. The stock oil pressure sender is a strange animal compared to most. Its signal is not a simple switch for pressure/no pressure but a pulse train of varying duty cycle. The ECU uses this to slightly adjust idle speed based on oil pressure, mainly when cold. Those without it are unlikely to notice any difference.

The gage is even stranger. It operates in a thermal loop with the sender, which has a small resistance heater wound around a bimetallic strip with a contact on one end. The duty cycle of that contact is output to the ECU but also drives another small heater/bimetal strip combo in the gage which is mechanically coupled to the pointer. It's why, if you look closely, you'll see the pointer oscillate slightly.

I'm simplifying a bit but you get the idea. It's a odd system that works well enough. I suspect the sender was engineered to be "digital" because the ECU input is and the gage was done that way to follow along. Just a guess though.