Now that you mention it, of note: I only noticed this happening after installing a "T" for the turbo oil line. Before it went to the "reputable" builder, my block had an oil feed port near the turbo. After coming back from the "reputable" builder, it did not.

 

I am also using a T to feed turbo and OP sender. Is it possibible we need a one way check valve on the line going to the turbo?

 

doubt it on the check valve. bundy, you running your sender off of a "T"?

 

I don’t have any T in mine. Sender is in the factory 1994 spot turbo is fed from the factory turbo feed location on the exhaust side of the block. 1994 block is set up for turbo.

Bob

 

Adding the ground strap to the trans plate changed nothing for me.

Bob

 

Only if you're using an aftermarket gauge with a one-wire sender with high resistance.

 

Everything with my gage and sender is OEM 1990 vintage.

I can get the gage to do the same thing pushing in the clutch and applying a hard jab to the throttle. Don't think that would be knock in that instance. Seems to be more rpm and accelerating rpm related than load.

Im stumped.

Bob

 

There isn't something in the engine that sucks more oil at high RPM, is there? I couldn't think of anything, but wanted to make sure I wasn't having a total brainfart.

 

I've got an Accusump which is like a big old capacitor full of over two quarts of oil feeding into oil galley in the block a couple inches from where the pressure sender is with a -10 line. Even if the oil pump sucked in some air I don’t think the actual pressure should fluctuate down much until the Accusump was empty.

When I turn the key on I’ve got ~30 Psi reading on the gage before I hit the start button. And it will hold it for a minute or so before it discharges down all the way.

Bob

 

Pressure senders are fragile. They get damaged when dropped.

Maybe it is now malfunctioning when vibrating at a certain frequency - which explains the clutch

 

Any updates

 

Well yesterday was my first track day since motor rebuild, Accusump install and Breather/crankcase evac system install. Quite a bit of testing and tuning on the road with the only apparent issue being the oil pressure gage.

The breather system sucked out mass quantities of oil after hard left hand turns and created great smoke screens, the Accusump seems like it quit working, and the oil pressure gage is still wonky.

I diagnosed the breather system was sucking oil out through my slash in the exhaust when the catch can got a big slug of liquid oil in it. The pressure gage on the Accusump itself just stays at 80psi and it doesn’t appear the valve is opening. The pan became over filled but draning it down didn’t help the breather issues.

On the plus side the car seemed to run really well even with the occasional smoke screens it was leaving and I was the fastest car at the SCCA time trial by like 5 seconds. I don’t believe the oil pressure sensor is reading knock. The plugs looked perfect after pulling them out after the first big oil smoke episode. The oil was not going through the combustion chamber.

Bob

 

Did you leave a breather port on the passenger side of the valve cover? I put one on that side and on left corners I dumped oil by the quart, and I'm not exaggerating. I now run only one on the driver's side and get a minuscule amount of oil through the line.

 

Yea I’m beginning to think that it is the OEM PCV port that doesn’t work as a breather at all. Hard left hand corner with hard acceleration and like a cup of oil all at once shoots out I’m guessing based on my experience.

I also have a drain back to the very bottom of the pan that may be the problem. But if the oil doesn't drain back somehow the slash cut will suck it all out the tailpipe when it starts to fill up.

I tried loosening the fitting to the hose going to the slash cut thinking it would pull less vacuumed and the result was oil spewing in the engine compartment.

Bob

 

http://www.youtube.com/watch?v=5hsQYiIHiq0

Smoky embarrassing.

Bob

 

I decided to put my timing map back to the way it was on the dyno and use my electronic detcans to see if I could hear any det. I was surprised at how obvious the detonation sounds. Unfortunately I wasn't able to look at my oil pressure gauge at the time since I was trying to get a quick pull in traffic. I removed a degree of timing in the suspect area, and I'll give it another try. Once all is tuned, I'll see if the OP gauge is still bouncing around.

 

Another update: I did some "listening " this morning on the way into work, and was able to watch my OP gauge. The knock I hear with the detcans is directly related to my OP gauge flickering. I listened to the car without the detcans, but couldn't hear any audible problem. Again, it is very obvious with the detcans.

 

Do you have a knock sensor? Mine is not seeing any knock and I can still get the oil pressure gage to freak out without a heavy load on the car.

Bob

 

No knock sensor, just listening with electonic det cans. I haven't tuned out all of the knock yet, but I'm working on it. Once I do, I'll really flog it and see if the gauge still moves. It seems to be in my 230kpa row. I was initially running 17*, I stepped down to 14*, and I'll see how that works this afternoon.

 

I just "fixed' my Oil pressure sender. It's now reading 60-90psi, is this possibly due to the turbo oil restrictor ~14" away from the sender?