I have a 1996 Grand Cherokee v-8, auto tranny, all wheel drive with 207,000 miles on it. It runs great until you start driving it. When you approach a stop sign or slow to a stop, the oil pressure goes from just over 30 psi to 0 and the engine dies. If I tap the gas pedal and rev the motor up just a little, the oil pressure goes back up to normal. Please help me. Looking for advice or suggestions. Thank you.

 

What happens at idle in drive, without touching the gas pedal, and holding the brake at a stop.
And Welcome to CF!

 

When at an Idle, stepping on the brake, in drive, it usually idles fine, but when it starts to warm up, the oil pressure does the same thing, going from just over 30 psi to 0, and the motor dies. I wait a few seconds and restart the engine and the oil pressure goes back up to 30.

 

It ususally only does it when I am coming to a stop or when I am stopped and sitting still.

 

My thoughts (I am very unfamiliar with your vehicle)

If your oil pressure is dropping as it dies, then that is most likely a sign of it dying. If your rpm drops your oil pressure will too.

On the other hand, if your oil pressure drops before it dies, it is probably shutting off due to low oil pressure. I know some vehicles are equipped to do this. I dont know if yours is.

Typically this happens because your oil pump is not able to pick up oil. Judging from the fact that it does it when you approach a stop, and at idle, I would say your oil level is too low.

Just curious... Did you recently run an "engine cleaner" through the oil?

 

Moved to GC Tech...

 

The oil pressure drops b4 the engine dies. it will go to 0 for atleast 10 seconds b4 the engine dies. The oil level is right on according to the dipstick. I haven't used any engine cleaners either. I have had the vehicle roughly a year and maybe it just needs an oil change. I haven't driven it much do to the fact that i just got the title for it. I bought the vehicle from my friend who's dad owned it b4 me and he passed away making for getting the title a problem.

 

you might try to run some engine cleaner through it and see if that solves your problem if not you could have a bad oil pump is my quess

 

how long does it take for the oil pressure gauge to move when you first start it?
could be a pump going out on ya, or just your sending unit/oil sensor.

 

I am going to say go ahead and swap out the oil pump... Cause if it was just a sending unit or gauge issue...

 

I would drop the pan and see if sludge buildup on pick-up screen. If clean then go for oil pump. I would hook up manual oil gauge and see the "real" oil pressure. It could be bad oil sender unit sending wrong signal to computer.
Since the cheaper will be to change oil sender unit first, then drop pan and inspect the pick-up screen. Oil pump last.

 

DO NOT run an engine cleaner unless you intend to change the pump afterwards. With 200,00 miles you are going to have a lot of junk built up in the engine that an engine cleaner will knock loose. This WILL clog your pickup screen on the oil pump. The only way to undo this is to remove it and clean it or replace it. Engine cleaners are fine when used regularily, but not for the first time on a 200,000 mile engine.

Best bet, use an engine cleaner, twice, then pull the oil pan, replace the pump and pickup tube with screen, and clean the crap out of the pan. Id bet you have a bad pump. The pump is mechanical, and if it is happening consistantly at low rpm and the engine is dying, its not a bad sender.

When you fill the engine with oil, make sure your dipstick reads correctly after you put in the amount of oil called for in your owners manual. If someone replaced the dipstick at some point, you will not know if its right until you put the correct amount of oil in it yourself, then see what the dipstick says.

 

Replace the sending unit before anything else and see if the problem is solved. Start cheap, then move on from there. Do NOT put any snake oil cleaner through the oil system, you're just asking for problems when you do that.

 

I am having the same problem, except engine doesn't shut off. I actually changed the oil pump & now the gauge reads zero. I kinda did it backwards though, I should have started with the sending unit. Does anyone know where I can find the sending unit on a `97 V8???

 

I think it might be at the back of the intake manifold next to the distributor.