i noticed today that when i decelerate the oil press. gauge says the oil pressure goes down, and on in hard braking it reads 0 press. the gauge dropps at a normal fall, it just dosnt fall right off. so could this be my sending unit, or could my pump be on its last leg. and yes there is the correct amount of oil in the engine.

thanks
anthnony

 

Umm 0 oil pressure is just not good. I can't see why the sending unit would work correctly at partail acceleration and then drop down to 0 at idle. Might as well try as it about 8 bucks. Otherwise I hope you like pulling your engine. Good luck.

 

the oil pressure is not at 0 at idle it is at 30 psi, it only dropps while decelerating. and yes it would suck to have to pull the motor so that is why i am driving my supra right now.

i have another question. i know on some engines the computer uses a different sending unit than the gauge, so what my question is, would the computer through the check engine light on if it detects low oil pressure? also where is the sending unit for the gauge located on an 89 350 TPI?

thanks
anthony

 

Stupid question, but you do have the crankcase full right? Sounds like the oil is sloshing away from the pickup, which takes quite a bit of lateral acceleration...or a low oil level.

 

If you brake and the oil pressure goes to 0psi that would suggest all your oil is in the front of the pan and you're not full...


Oil pumps dont "fritz" they're not electrical like your fuel pump, they're about as mechanical as mechanical can get, If its not your oil level, consistancy, filter, sending unit, or an extremely extremely worn pump, it could be your bearings.

But i'd say its a simple case of womanitis and you forgot to check your oil

 

Yes, the car will throw a code when engine oil is low. My guage tends to dance around as well...but always on the high side. I've seen this problem MANY times on MANY different cars in the GM line.

 

I don't know about the newer electronic dashes but the mechanical gauges don't interface with the ECM. I can't see how low oil pressure would "throw a code". Low oil level + high volume oil pump = sporatic oil starvation, been there, done that, have the shot bearings.

 

I think it was my knock that went off when I was low. It was a few years ago so I don't recall. Was cruising down the highway when Mr. SES came on. Pulled over, everything seemed fine. Checked oil and it was below the dipstick.
Filled her up and was on my way. 3 years later and it has never come back.

 

yes i checked the oil and it is full. i just bought the car about 6 weeks ago and have put almost 700 miles on it and it has just started doing this. so i take it that on my 89 it will not through the check engine light when it detects low oil press. i have not had the time to change the sending unit this week because i am at work at 7:45am and get home at 5:00pm then have classes at 6:00pm to 9:00pm so i am very busy. hopfully i will get a new one in there this week.
thanks
anthony

 

Me thinks the pickup fell off the oil pump. BTDT. Now they get
tack welded on.

RBob.

 

...or bolted on with Loctite red on the threads if you're using one of the slick new Melling 1055x pumps. I just put a 10552 in when I did the pan swap, love it! Only 10% more volume, instead of the usual 25% increase for high volume.

Enough volume budget to keep pressure stable on the track at extended high revs, but not put as much load on the dist gear and bushings as a regular HV pump. Great idea. Throw in the bolt-on screen, no welding required, 3/4" tube diameter, and I'm a happy camper.

 

so say it is my oil pump, would jacking the motor up by the bell housing be enough to get the oil pan off or would i still have to have an engine hoist?

 

Hoist

 

I actually had to change my oil pump shaft so this is what I did. I got my friends hoist unbolted the motor mounts and the bolt that goes through the tranny crossmember into the tranny mount. Then I lifted the motor straight up until it started lifting the car then I dropped the pan (it is really tight but it can be done) Proceeded to unbolt the pump and work with it from there.

 

ok i plan on buying an engine hoist soon. i was under the car replacing the sending unit and i hit the bottom of the oil pan and i herd a rattle in there. i guess that is the oil pickup that has fallen off but i cant be for sure until i test srive it after puting the new sending unit on. i plan on finishing it tomorrow because it started to rain on me today.

if i do have to pull my motor i will go ahead and do a few mods and fixes that i have been wanting to do like replace the starter with a light weight one, put better plugs and wires on it, high performance distributor, headers going into 2 high flow cats, into an x-pipe, and out of nascar boom tubes out the sides of the car right in front of the rear tires, and probably switch the stock oil pump to an aftermarket high flow oil pump while im at it.

i will see if the new sender fixes the problem.

what is really the kick in the *** is that i just bought this car for $3000 about a month ago and had only driven it for 2 weeks when the problem started oh well you win some and ya lose some.

thanks
anthony

 

well bad news boys and girls, the oil sending unit was going bad but it wasnt the problem. the pickup assembly has fallen off. so the good news is that when i pull the motor i will put the exaust on it i want and change the starter, put the high flow oil pump and performance distributor on it as well as new plugs and accel race wires. so now i need to buy the hoist and all the exuast stuff.

guess i will make a good thing out of bad!

thanks
anthony