Under what conditions does the engine light come on? 1984 GM LS

[Maj]

Hi all

I'm guessing there are a set of standard conditions that the engine light comes on? Like overheating for example. What other fault conditions make the light come on?

In my case it's flickering when the revs drop as I put the car into gear. Does it come on when the revs drop too low? Or is it trying to tell me something else?

Thanks

[87gtVIC]

Overheating or low oil pressure. I suspect you have below 8 or so psi of oil.

[mrltd]

The light comes one when the motor needs to be replaced. Yours has wasted bearings. It's like 230*F or less than 8 or 10 psi of oil pressure.

[cld783]

oil pressures probably on the low side, when the idle drops it slows the pump. it will likely run a long time that way.

[Maj]

Thanks for the replies

I'll check the pressure. If low oil pressure is the issue would it help if I used a heavier weight oil or something like stp oil stabiliser?

[91waggin]

This is a standard problem with 302 engines that have the lopo cam and firing order. The firing order has the tendency to trash the main bearings over time and eventually the oil pressure will drop at hot idle to make the "Engine" light flicker. The engine will probably run a long time like this, but it will eventually start to knock at hot idle. If your idle speed is set too low (since you don't have EFI), the oil pump might not be spinning fast enough. You want about 700 rpm at hot idle. If you indeed have low oil pressure, switching to a 10W-40 or even a 20W-50 might make the light go away and make your engine last longer. These engines have been known to last a long time with this problem as long as you're nice to them.

The engine light comes on when oil pressure drops below 6psi or if the engine temp rises above 250 degrees F.

[Maj]

Time for an oil change then.

Thanks guys

[1990LTD]

It is jokingly referred to as the "replace engine light" - Of course it'll run for a while with low oil psi, but eventually it's either gotta come out to be freshened up or replaced with a fresh(er) one.

[sly]

sometimes it's simply due to the carb/cfi/throttle body being gunked up and needing to be cleaned. It'll drop idle RPM sometimes just enough that it'll run almost ragged and blink the light. Might check to see if the idle is above 650 rpm when warm. Old grungy oil will do that too. My mom let the oil change go for 16K once. This was on a 1.9l 4-banger 93 escort wagon. oil took over half an hour to ooze out. and it was warm too.

I had this oil light problem with a carbed chebby b-body. It would run... barely... the idle set screw was stripped out and wouldn't hold the idle speed proper. I have no clues about setting base idle on CFI though. EFI has no user changeable settings and the throttle stop screw should never be touched.

[mrltd]

Yeah, it will run like that for years. I had one that I beat the living crap out of that. The light was on going down the highway with 20W-50...And the previous owner drove it like that for at least a year and a half.

[86VickyLX]

If you do decide to change the engine. May I suggest an '86 or newer, just since they wear better due to the roller cams.

[Maj]

Yeah, it will run like that for years. I had one that I beat the living crap out of that. The light was on going down the highway with 20W-50...And the previous owner drove it like that for at least a year and a half.

I feel more relaxed already

My light is just flickering, for now anyways! :smirk:

[johnunit]

definetely consider bumping the idle up, even as high as 800RPM, just to keep the annoying light off.

[351m]

I thought the engine was torn down for this once already?

[Maj]

I thought the engine was torn down for this once already?

Nope, just pulled apart far enough to replace the bad lifters . . . . .