Red engine light

[91merc]

I got a red engine light on my 85 and it's acting sluggish, what's the difference between the yellow "check engine" and red "engine" lights on these cars?

[Stocker]

The red "ENGINE" light comes on when oil pressure is too low (below either 6 or 10 psi, if memory serves) or coolant temperature is too high (250°F or above).

[Kodachrome Wolf]

The red "ENGINE" light comes on when oil pressure is too low (below either 6 or 10 psi, if memory serves) or coolant temperature is too high (250°F or above).

Yellow "Check Engine" on '89+ is an actual check engine lamp. Like Stocker said, the red "ENGINE" light is for one of those two issues.

[91merc]

Well the coolant temp sensor has bare wire on the little snap plug. And I might've disturbed it when I pressure washed the engine, oil pressure wiring doesn't look the best either

[gadget73]

That would be the "replace engine" light. Unless its a bad sensor, fair bet she's fucked if you've been driving with that on for any amount of time at all.

[Stocker]

Well the coolant temp sensor has bare wire on the little snap plug. And I might've disturbed it when I pressure washed the engine, oil pressure wiring doesn't look the best either

With the engine cold and running, disconnect the wire from the coolant temperature switch (this is the one on the intake manifold - the one on the heater hose fitting is the temp sensor for the ECU). If the light goes out, the problem is the switch. If the light remains on, either the wiring is shorted or the problem is in the oil pressure side of things. Disconnect the wire from the oil pressure switch - if the light goes out, either the switch is bad or your oil pressure is next to nothing.

[WagonMan]

Doesn't an 85 have the "low oil" sensor in the oil pan? The sensor can be stuck or the wire going to it may be shorting out. WagonMan

[Stocker]

Doesn't an 85 have the "low oil" sensor in the oil pan? The sensor can be stuck or the wire going to it may be shorting out. WagonMan

That's a separate light - optional on Fords, and I think it says "Check Oil" (my '85 is a low-series car and doesn't have it).

[Lincolnmania]

does it go out when you rev it up?

[91merc]

The first time I drove it about 15 miles, parked it for about 10 minutes and it was on right from startup, then I went under the hood and wiggled some various wires and it stayed off for about 10 more miles, the last 5 or so miles there was no knocking or coolant smell, just a little sluggish

[91merc]

The light is staying off right now, but I haven't actually moved it at all yet

[Tiggie]

If the coolant temp sensor or the oil pressure sensor grounds due to faulty wiring and/or a faulty sensor, the light will turn on. By what you are describing, that sounds like your issue.

A steady on red engine light for actual temp or oil pressure reasons basically means turn it off ASAP or you're gonna nuke it.

[91merc]

If the coolant temp sensor or the oil pressure sensor grounds due to faulty wiring and/or a faulty sensor, the light will turn on. By what you are describing, that sounds like your issue.

A steady on red engine light for actual temp or oil pressure reasons basically means turn it off ASAP or you're gonna nuke it.

I think you're right on the ground problem cuz it stayed off on my 20 mile commute to work and ran real good. If the ground problem is the case, would that basically fool the computer into thinking the engine was about to grenade and throw the car into limp mode and thats why it was sluggish?

[Lutrova]

Do these things have a limp mode?

[91merc]

Or is it rather to do with the fact that the coolant temp is one of the variables used for the air/fuel mixture?