Help With Oil Temp Sensor
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Le Mans Master
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From: Akron Ohio
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St. Jude Donor '09-'10-'11
Help With Oil Temp Sensor
On my 90 the oil temp sensor has 3 wires coming off it. Ground, one to the gauge and one to the ECM. I am replacing all the gauges with aftermarket analog and got new sending units with them. My question is, what does the wire to the ECM do? Is this required for the engine to run? If I use the OEM sensor do you think it will display the proper temp on thr new gauge?
Race Director
Joined: Jun 2004
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From: WI
Hmm my '88 had a single blade connector sender above the oil filter. BTW it was difficult to fit an aftermarket oil temp sender there so I used the back not bottom of the oil pan. When the engine was out it could have been re-sized perhaps.
The only benefit I can see of the ECM having oil temp would be to read it in a data log. I am not experienced with '90 code so someone else will have to chime in on if the ECM actually uses it and will set an error code.
OEM sender will not output correctly to an aftermarket gauge. I've tried and they are calibrated differently.
The only benefit I can see of the ECM having oil temp would be to read it in a data log. I am not experienced with '90 code so someone else will have to chime in on if the ECM actually uses it and will set an error code.
OEM sender will not output correctly to an aftermarket gauge. I've tried and they are calibrated differently.
Thread Starter
Le Mans Master
Joined: Oct 2007
Posts: 9,682
Likes: 3,433
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
Hmm my '88 had a single blade connector sender above the oil filter. BTW it was difficult to fit an aftermarket oil temp sender there so I used the back not bottom of the oil pan. When the engine was out it could have been re-sized perhaps.
The only benefit I can see of the ECM having oil temp would be to read it in a data log. I am not experienced with '90 code so someone else will have to chime in on if the ECM actually uses it and will set an error code.
OEM sender will not output correctly to an aftermarket gauge. I've tried and they are calibrated differently.
The only benefit I can see of the ECM having oil temp would be to read it in a data log. I am not experienced with '90 code so someone else will have to chime in on if the ECM actually uses it and will set an error code.
OEM sender will not output correctly to an aftermarket gauge. I've tried and they are calibrated differently.
Thread Starter
Le Mans Master
Joined: Oct 2007
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From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
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St. Jude Donor '09-'10-'11
Anyone else know why the ECM needs an oil temp input?
Melting Slicks
Joined: Jul 2005
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I know that on the LT1 cars - the ECM would go into a "safety mode" when the oil temp hit 300 F. Power would be restricted (pulling timing), both cooling fans would run full time etc. etc. Not sure if the same is true on a 90, but it's quite possible.
Thread Starter
Le Mans Master
Joined: Oct 2007
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From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
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St. Jude Donor '09-'10-'11
Thanks for the image, but I also have that page someone scanned for me before. The only thing it says is "Oil Sensor Input" it doesn't say what it does with that information and/or if it is required.
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Suckin' gas, haulin' ass.
Joined: Apr 2010
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From: Newport News Virginia
We need to see the wiring diagram for your ECM. Also, the block that says "See engine data sensors" may also help, we just need the 8th number of your VIN to get the correct page.
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Le Mans Master
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Race Director
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From: moraga ca
The oil temperature sensor is above the filter and has one blade. The oil pressure sensor is on the block behind the intake manifold to the driver's side of the distributor. This has three wires.
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Le Mans Master
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St. Jude Donor '09-'10-'11
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The sensor behind the distributor is a combination of oil pressure sensor and oil pressure switch. The sensor goes to the dashboard oil pressure gauge. The oil pressure switch bypasses the fuel pump relay so you'll have fuel pressure if the relay doesn't work for whatever reason.
In earlier L98s there was a separate oil pressure sender and oil pressure switch.
In earlier L98s there was a separate oil pressure sender and oil pressure switch.
Safety Car
Joined: Jan 2004
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As shown in the '90 circuit diagram I posted above
Le Mans Master
Joined: Aug 2000
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From: Australia
Thread Starter
Le Mans Master
Joined: Oct 2007
Posts: 9,682
Likes: 3,433
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
The sensor behind the distributor is a combination of oil pressure sensor and oil pressure switch. The sensor goes to the dashboard oil pressure gauge. The oil pressure switch bypasses the fuel pump relay so you'll have fuel pressure if the relay doesn't work for whatever reason.
In earlier L98s there was a separate oil pressure sender and oil pressure switch.
In earlier L98s there was a separate oil pressure sender and oil pressure switch.
Le Mans Master
Joined: Aug 2000
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From: Australia
Racer
Joined: Jun 2006
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I believe in 1990GM combined the oil temperature and pressure sender into one unit and mounted it over the oil filter. When I helped install the FIRST intake on an 87 vert, the canister type pressure sender would not fit behind the distributor so we converted to the three wire temperature/pressure sender. It was pretty easy to do, and when I drop my new 355 in my 88 next month I'm going to convert mine. It makes changing the pressure sender much easier.
Last edited by Corvette40; Sep 1, 2012 at 11:13 PM.
Suckin' gas, haulin' ass.
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From: Newport News Virginia
I believe in 1990GM combined the oil temperature and pressure sender into one unit and mounted it over the oil filter. When I helped install the FIRST intake on an 87 vert, the canister type pressure sender would not fit behind the distributor so we converted to the three wire temperature/pressure sender. It was pretty easy to do, and when I drop my new 355 in my 88 next month I'm going to convert mine. It makes changing the pressure sender much easier.