The oil pressure light on my 86 2.8L flickers on and off. It seems to only do it on decelleration, not at idle or when accellerating.The oil was changed 3 weeks ago with Castroll 5W30 and the oil level is good. I replaced the oil pressure sending unit. It is still doing the same thing.

 

Ever since I got my caqr when I stopped fast (pedal almost to the floor) My oil light would go on.

I had the cheapo oil in my car.

TYhis time I has to slow down fast.

Oil light came on, the oil was full.

Engine starts making all sorts of noise

DOH!

Engine now knocks... Now it's not driven anymore and is up for sale.

 

your oil pump might be going bad...dunno, but might be an idea. That would really suck. I'm sure there is another explination for it, but it's probably something electrical. Pull the insturments and check the connections to the light. It might be loose.

 

I have always heard, and experienced that GM oil pressure units suck. Almost any GM car after 100k miles, it starts going out/acting up.

 

How does the front of your motor look?

Reason I ask...

Many of the bolts on the front of our motors also cover up oil passages. When I originally assembled my 2.8 in my 83, oil leaked out of the front. Did the HB sleeve trick -- still leaked.

I didn't find this out until I re sealed the timing cover. As I was backing the bolts out, I noticed that many of them had oil on the threads.

I put some RTV on the bolts before re-installing them. Now I have a nice dry front and no flickering from the oil light.

Don't discount the possibility of a worn oil pump though.

 

I put an oil pressure gauge on last night. Cruising around it is running from 60 - 80+ PSI. It holds around 60 at idle. Seems like good numbers to me. The Chilton manual says 60 PSI @ 2000 RPM.

 

Sending unit and/or guage is bad. I suggest you stick with the mechanical gauge. Also, I am not sure where the oil pump pickup unit is on a 2.8, but it's not uncommon for certain motors to experience "starvation" either under extreme acceleration or deceleration, depending with the oil pickup is located in the oil pan.

I would "simulate" that "hard braking" again, to see if the mechanical unit shows a decrease in oil pressure under hard deceleration. Either oil may be going to the front of the pan (if the pickup is in the rear of the pan) or your pickup may be loose and not getting enough clearance from the pan (if in front) or lifting out of the oil (if in rear).

Use the mechanical guage to test these...idiot lights are for ....

 

ok get this,mine has the same problem, flickering oil light. ok
well,since i bought the car 3 years ago,its always done it since ive had it. It only does it once the motor is really warm,and im stopped at a stoplight.Now in theory,the amount that this light has come on,my motor would be seized right now if their really was no pressure! right...right!. Ok,so,i replace the oil pressure sender,...nada,still does the exact same thing! Now heres where it gets weird....
i unplugged the oil pressure sender wire...AND IT STILL DOES IT! hows this possible with no wire to read!!! It must be an electrical thing. Now,when the light is on,the motor doesnt stutter or even slow down,it just runs normal! Some one tell me whats going on! Ive heard this is a very common problem but have never heard an answer. Also ive done searches on here and cant find an answer.Please help!

 

I now have the same problem except it does it when at idle. This happened right after I washed my engine.
How hard is it to change the oil pump?

 

It's a pain in the ***. You have to pull the pan off the motor, which means that you have to unbolt the trans(I think, might be wrong on this), undo a couple of motor mounts so that you can pull the pan out and clear the cross member. then you have to actually change the pump. it sux.

 

im tellign you check your oil pump ASAP i had an 84 camaro last year and i alwase checked the oil in it and the oil light would flicker about a week later my engine sounded like a machine gun being shot off i will personaly never ever ever buy a camaro with a 2.8 in it in fact i wont even touch an s10 with a 2.8 in it for that matter i hate those engines so much but seriosly do ur self a favor if you plan on having that engine last and check that pump out dont trust that it was just electrical liek i did and get proved rong.

 

Or remove the idiot light from your cluster and mount that mechanical gauge in there!

Honestly, don't trust the idiot light, but don't distrust it either. The mechanical gauge is your best bet, and that's the only reason I'm not on the "check the pump" bandwagon... now maybe I should replace the sending unit on my v8. It's read 0 psi since I bought it in October 2001.. would really suck if the pump failed.. I wouldn't know till I heard the knock =\