I have recently done a H/C install to my '01 Z. I started it up and had good oil pressure(65 psi) via a self ported oil pump. When I'd get on it, it would go up to about 78-81 psi. After driving about 25 miles or so, I noticed the oil pressure went to ZERO. I turned off the motor and coasted home. I hoped it was just the sending unit, it wasn't. I took the valve cover off and ran it about 10 seconds. No oil came out from the pushrods. I rechecked the oil level and it was full. Next, I went and got a GM oil pump and o-ring and installed it. When I started it up STILL NO OIL PRESSURE!

The only thing left is the oil pick-up tube I would think.
ANY SUGGESTIONS?

 

Possibly the pickup tube is clogged or something similar. To be honest with you this is kind of strange to me. I'd be better off letting someone else give you a definate answer, if there is one.

 

Yea, it defenitly is strange. I guess i'll take the pan off tommorow.
Thanks

 

You mean you think there is a problem with the tube? Are you sure you installed the O ring properly?

 

If it had pressure and then had none, I highly doubt that could be the o-ring's fault. I really don't know what would give 0 pressure. Maybe somehow you spun a bearing. I still think you would have some pressure though. It would just be real low. For some reason I think it's your oil pressure sending unit. I know you said it doesn't come out of the p-rod holes, but maybe it's not cranking enough to send the oil that far or something. I just don't see how you could have oil pressure and then have zero.

 

put a mechanical gauge in it to see if its a problem with the sendor/wiring.

 

put a mech oil gauge on it. you have to have some oil pressure, hopefully. does the engine sound normal? if it had no oil pressure you would surely know it, by how it sounds like when you first start your car when you change oil. it would not run very long without oil pressure and you would defentaly know it. just my .02

 

I'm gonna take the valve cover off again and see if any oil comes out after the new pump install. Hopefully it will, if not I will get a mechanical guage. I too hope its the sending unit just not giving the right singal. I'll keep ya'll posted on what I find. Thanks!

 

i have a similar problem right now, pretty sure you ahve junk in the pickup.

 

First off, IT IS A PAIN IN THE ASSSSSS!!! I just now at 13:35 got the pan out. When you take the k-member bolts out, take four of the bolts out but keep the front two(one on each side) in. You will have to pull down on the k-member in order to get it out. Plan on buying a new pan gasket. I have an A4, and I had to take the one crossmember nut off the tranny crossmember. I also took out the starter, it made more room. Its only two bolts. I had just finished a h/c install when I had 80psi oil pressure via a high flow oil pump, when all of the sudden my oil pressure went to 0. After changing the oil pump(which is easy, except for that damn 1 bolt holding the pick-up tube on) I turned the motor over to find still no oil pressure. Anyway, my pick-up tude was completly blocked! I MEAN COMPLETLY! It look like a paper towel or something. I getting a new oil pan gasket ($50!) right now. Good luck and be patient!

 

Check the oil gallery plug. It is noted in Vizards book I believe that this can blow out and fall into the pan resulting in a complete loss of oil pressure.