96 3.1 Into 95 OBD1

[xcdizzyx]

I had a 96 Grand Prix 3.1 with obd2 but the body was trash so I swapped the engine into a 95 with a good body but I didn't get the chance to take the pcm or wiring harness before the car was gone. So far engine seems to run fine and all I needed was to swap the fuel rail harness and egr but the issue I have that's stopping it from being complete is the coolant temperature sender. On the 95 engine the coolant temp sender was in the cylinder head but the 96 doesn't have a second sensor so I have no temp reading on the dash. I've had a few ideas for fixes but I'd like to make the stock gauge work instead of adding a new gauge. Any and all ideas are welcome

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[robertisaar]

your 96 had a single coolant temperature sensor mounted in the lower intake manifold(should be a 3-wire unit) as opposed to the 95-earlier having a 2-wire temp sensor in the same location and the 1-wire sensor in the head.

if I were you.... I would grab a connector pigtail from a 96+ junkyard car that uses a 3-wire sensor and a new 3-wire sensor meant for a 96 grand prix w/3100 and splice it in.

you should have had to swap knock sensors around too.... the 96+ uses a 100Kohm sensor while the -95 PCM expects a 4Kohm sensor.

[xcdizzyx]

I didn't know about the knock sensors and I haven't switched them what would be the side effects of not changing them?

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[robertisaar]

i would have expected it to set a code nearly instantly and then run with a defaulted 10 or 15* of timing retard, I can't remember which.

otherwise, if it doesn't set a code, it may just completely fail to detect detonation.

[xcdizzyx]

So I should probably get around to changing them soon then. Being as the car is still obd1 I don't have a way to check the engine codes but the light is on. And the engine dies under load could this be the cause?

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[robertisaar]

it certainly is possible, at least a knock sensor is cheap and fairly easy to change in-car.

do you have any kind of coolant temp sensor hooked up to the PCM? if not, that could also cause some huge drivability problems.

[xcdizzyx]

Yeah the stock one in the pcm is still in place in the lower intake

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95 Grand Prix 3.1