89 supra non-turbo oil pressure question
 

My 89 supra non-turbo is constantly losing oil...but i cannot find any visible leaks, when i check oil it is clean, there is no smoke or odor (like if it was burning) and the oil pressure gauge goes from just above 0 marker when the car comes to a stop to just below 40 lb/in marker when i'm on the hwy going about 70mph...that was right after i had an oil change...the next day it stayed right above the 0 marker between the marker right above 0....i have to add oil constantly! I checked for leaks ...NONE:rant2:

what is going on??

The answer is very simple... you're leaking oil or you're burning it. That much oil and your spark plugs would be coated in solid black carbon buildup... if there's wet oil on the plugs and the insulation boots of the wires then the leak is either the valve covers or one or more of the big center hex plugs holding down the middle valve cover.

After eliminating the oil being burned in the cylinder or leaking out the inner part of the valve covers go buy a UV dye kit for tracing oil leaks and follow the directions.

Yea my valve covers was leaking down the back on to the tranny and where the spark plugs were pull out one of the wires and see if it's wet

We have been checking the spark plugs, the valve covers, bolts and cams... found my #1 plug a lil too wet with fuel....checked injectors and i do have a bad injector which i will be replacing tonite ( those lil suckers are expensive!:rant2:)
BTW ....I drive approx 200 miles a day commuting to and from work....would that make a difference in my oil consumption?

Also, is the oil pressure gauge suppose to drop so low when i come to an stop/idle then raise back up when im at 3000rpm?

We just repaired a blown head gasket last week...took head to machine shop, replaced rear main seal...replaced oil sensors, switches, gaskets, filters, several oil changes but we still need to replace the oil pump....its making some noise.

Having said that, my point is that my engine is clean and so is under the car....i clean & paint my parts....not only for looks but to help pin point any leaks. :naughty:

As for noise...Last night we had to take out the crankshaft timing pulley. My question hear is, does the pulley come with a washer that seats against the timing cover and pulley or is it 1 piece that holds the timing belt in place? The pic on the TSRM looks like its only 1 piece. :dunno:

Mine is in 2 pieces...and the washer has been moving around and made a deep grove in my lower timing cover ...as well as chewing up my timing belt while the timing belt is slipping off pulleys.

I put a spacer against the inside timing cover and the timing pulley so it would keep the pulley's washer in one place so the belt doesnt slip off....so far its working :bow:....although I want to replace cover and crkshft tim pulley asap.

All in all.....car runs very nice :cool: (wish I had turbo tho!) but I got this at an auction for $300...so I cant really complain...its teaching me a lot...at least I'm more comfortable dismantling the engine since the BHG.

The oil pressure goes up and down when driving and stopping because the pump is gear driven by the timing belt I think. I have a fully rebuild 7mge and its not leaking or using oil and my oil pressure goes up and down also.

Ok cool...at least that gives me sum piece of mind...thanx Sony!

Given the mileage you're putting on the car (although this is adviseable for anyone with such an old car) you would be wise to send the other injectors off for professional cleaning, blueprinting and screen replacement. Toyota specs allow for variation to the point of being ludicrous. If an injector is flowing 5+cc less (or more) than the others it should be replaced, IMO.

Your oil consumption, per mile driven, shouldn't change much... the frequency with which you must add more oil on a temporal level will be much higher. Your engine's condition will also affect it; Low compression scores will cost you oil in a number of ways, for example (loss of oil seeping into the compression chamber, loss of oil through the PCV system, etc.). Also keep in mind that the oil seals rely on a sacrificial film of oil and old seals lose a lot more oil through old seals than through new ones (even new engines are always losing oil).

If I remember correctly, the Toyotas specification allows for as low as 6psi at idle. Should be over 30psi at 3000RPM.

No, there are no washers. The retainer wall is supposed to be staked in place on the pulley. I recommend replacing it with a new one, some people have had decent luck getting it tack welded back on but you MUST be absolutely sure it goes back on straight.

Yep ...tack welded it. Much better! :bouncy: