Oil pressure question

[Jonny Cash]

Im going to go ahead and change the sending unit, and see where that gets me. Ill keep you guys updated.

Im really hoping that my leak at the pump is the problem considering the car is off the road now, and Ill be under there when I do my clutch.

 

[DHMag]

no PCV VALVE, but there is a PCV system. on MTXs, it consists of the hose from the front valve cover to the throttle body and a hose from the throttle body to the valley area.

on my 0-100psi gauge, i see 15-20psi at hot idle, and 65-70psi cold idle. oil weight also has a factor in oil pressure(im using 10w40).

location of the OPSU: from under the car on the drivers side. look up between the block and firewall. it is located at the back of the block, near the trans. it has a single wire hookup.

 

[NotSoSlowSHO]

Sometimes I swear I can smell burning oil, but I always thought the slight smell was from it leaking on the block and burning off.

When you say PCV you are taliking about an ATX, or a Cali MTX? I have no PCV valve

I bet you are burning more than you think.

And nowhere did I say PCV valve. All I said was PCV. The SHO has a PCV system.

 

[Jonny Cash]

Did you say you are loosing oil? Are you burning any?

Ive recently cleared up a PCV problem on my SHO. It was DRINKING oil thru the intake because of it. I was loosing nearly a qt every 500 miles or so.

Anyways, injesting so much oil, the factory O2 sensors saw a lean condition, and my wideband saw a rich condition. I was also having pretty bad timing retard.

Once I fixed the PCV problem, oil usage went down, A/F ration went back to normal, and I found my lost power due to the timing being bumped back to where it should be.

Oil in the combustion chamber effectively reduces the octane of gas.

Lots of timing retard, lean condition, and running warm.

Sound familiar? Just a thought.

How did you fix the PCV problem??

 

[Jonny Cash]

I bet you are burning more than you think.

And nowhere did I say PCV valve. All I said was PCV. The SHO has a PCV system.

I do realize that. I misunderstood.

 

[NotSoSlowSHO]

How did you fix the PCV problem??

My PCV problem was a plugged throttle body port that the lower PVC line attatches to.. Ceaned it up, as well as did the PCV "mod" that many on the forum have done.

Im also going to put a catch can on the lower hose.

 

[Jonny Cash]

So Im in the process of changing the sending unit. Should I apply any kind of sealer on threads to prevent a small leak?

 

[Jonny Cash]

Ok so I replaced the sending unit, started it, and the OP went to 50 psi at cold start up, and went down to zero at idle at full temp. Nothing has changed. It also has a small leak. Should I seal the unit threads, or just bang it down tight?

Any suggestions now that I got that out of the way?

 

[Jonny Cash]

Bump as I really need help with this.

 

[SHOtimer]

Is their a reason that you haven't done your rod bearings, or considered swapping oil pumps?

Doug

 

[Jonny Cash]

Is their a reason that you haven't done your rod bearings, or considered swapping oil pumps?

Doug

The bearings are only 2 1/2 - 3 years old. They were done when Kirk installed the motor. I was even considering taking the oil pan off, but I havent had the time.

Swapping the pump is not something I havent really thought TOO much about. Would the pump just be weak? I know they dont fail often.

 

[SHOtimer]

They do not fail often, but their have been instances of weak ones providing low oil pressure. It would certainly be something to consider in your situation.

Doug

 

[Mr Anonymous]

Your oil pressure is fine.

Kirk and I chased phantom oil pressure problems with that motor for months. Mechanical oil pressure is exactly what it should be. We're convinced it was an issue with the Autometer gauge, probably a result of the way the oil pressure senders are teed. Considering that the car has been driven a lot since then and still has the same readings, I would not worry for another second about the oil pressure.

Definintely sounds like you have a temp problem though. Temp on that car with that bigass radiator should never get higher than about 195-200.

I suggest you get back with Ted B. (is he still incommunicado since Katrina?), send him a dyno sheet, have him tweak your LPM to eliminate the pinging and smooth the A/F, as well as lowering the temp at which the fan fires. You might also want to have the cooling system pressure tested in case there is a problem.

 

[Jonny Cash]

I was hoping you would chime in. Thank you.

Yes Ted B is still around, and he just reprogrammed my LPM for me 2 weeks ago.

I will change the guage and see what I get. I changed the sending unit today, and got nothing. Now there is a small leak coming from the unit. Should I seal it somehow, or just screw it down tighter?

 

[Endri_SHO]

They do not fail often, but their have been instances of weak ones providing low oil pressure. It would certainly be something to consider in your situation.

Doug

==========================================================================

i am with you man .. plus that 91 ive seen it from near and seemed like it came out of the factory.. could not believe that this is happening to this first gen SHO engine.. good luck man