My 82 280zx, for the last 2 days, has had low oil pressure when I turn left.. but the oil has been full..This morning the oil pressure just dropped while driving straight, and the only place I could get oil was circle K...I have 5w-25w Mobile 1 synthetic in there, that is what has been in there for years...the only oil I could buy was pennzoil 15-35w non-syn..I have always heard once you go syn. you can never change back but what is going to happen to my engine???It seems to be okay and does not drop the pressur when I turn anymore...What caused the pressure drop in the first place...Sorry it s so long please help///

 

before you start fearing the worse.. id check the oil pressure sending unit first.. check the connections or just replace the whole unit...

 

Yup, my gauge starting acting weird. It was just the sending unit. Very common problem on the ZX.

 

My sending unit was the same. My presurre just started fluctuarting then would not get much over 10. So i parked the car replaced the sending unit and all is good.

 

But my engine will not let me go over 700 rpm's

 

In any gear? That is crazy! What about revving it? Does it go higher than 700, then? I had a problem before when my radiator hose burst. It sucked antifreeze through the air flow meter and into the throttle body. It took me 12+ hours to find the problem. But my car wouldn't go past 2000rpms. Even when driving. It turned out to be that my throttle body was gummed up with antifreeze! I just sprayed carburetor cleaner into the throttle body. Then it blew out smoke, and it just screamed! ANd I said wow it worked! I was quite happy! But I don't know if that is the problem with yours or not. I am telling you what I have learned with experience. Learn as I go, I am by no means a mechanic. But I can do more than the average person on a car.

 

I have no idea what the prob.. was I changed the oil/filter and everything seems to be going fine Do not know what the hell the prob was the oil was a little watered down?? Everything is good now thx for all your input...

 

mixing some synthetic oil with regular oil is no big deal since the oil companies do it themselves with their semi synthetic oil products.

althought the sending unit switch/wires may have been a problem, i would seriously consider changing the oil pump with a NEW unit.

they do WEAR and a new one is easy to change and under $100.

how much for a blown motor?

jim

 

The whole blown motor was scratched because Sandy @ Jim Cook racing could not develop the multiport injection blower kit in time....I am goin turbo or may do something with a procharge..

 

sorry to ask this, but where is the sending unit??? Located on the oil pump???

 

It is on the side of the block underneath the spark plugs. It looks like a little cylinder thing with a wire plugged into it. It shouldn't be hard to see.

 

Why would your engine not let you go over 700 rpm's?

If that's the case, you have some serious issues.

 

As mentioned, there's nothing wrong with mixing synthetic and fossil oil.

However, watered down oil is a BAD thing. You may have a blown head gasket. I would check/change your oil again to make sure there's no more water in it. Any water in there will rapidly degrade the friction bearing properties of your oil, synthetic or fossil based.

 

Compression test is good.. No oil leaks in the gasket.. I seriously have no clue what happened But it is working perfect now except I am getting bad gas mileage...

 

Bad gas mileage means it actually isn't working perfectly. You have a fuel mixture problem to the rich side.

Do you have access to anyone with a good wide band O2 meter?

The fact that it's driveable means it's not too far out of whack but still enough to impact your mileage. What kind of mileage are you getting?

Could be an issue with your Air Flow Meter. If the ECU thinks it's open farther than it really is, it'll dump more gas in to compensate.

However, your narrow band O2 sensor should tell your ECU it's running rich and back the injector pulse off.

Really need to get a wide band O2 meter on it to fully diagnose.

 

Actually I can not tell exactly spedo does not work {tranny} but my tank is on E 2 days earlier than before.. I really want a halmeter, because my airflow meter does not have the adjustment screw. any info. on that??thx Paul