Well the days of me wanting to finish my engine swap and driving my car may be officially over after 13 years. Was doing a final stress test on the engine before putting her on the road, all started well 23-25lbs of oil pressure (3.4 dohc) running good for 15-20 minutes, went to check gauges and see 17 lbs, jumps back to 23. So I decide to sit and watch, pressure drops to 12 engine stumbles and goes to 3 so I quickly shut it down. Wait 5 minutes check the oil and it is full. Go to start car and see pressure during crank is at 35-40 figure I might get lucky, no, engine catches and now no oil pressure at all. So decision is to tear into this engine, replace with the original 2.5 (glad I kept all of it), or give up the ghost and call it a day. Sorry about the rant.

dan

Check your oil pressure sender. Sounds like it might be flakey.

If it's showing 35+ lbs cranking, and then drops off after the engine fires, it sounds like an electrical issue.
Temporarily install a mechanical gauge, and see what it really is.

Don't give up yet!

This is a mechanical gauge that I just installed, taking a break for a while getting fed up with it and other things in life need attending to. Owned this car for thirteen years now, longer than my first child, and the car only has 50 miles on it since I obtained. I would be happy just to drive it to a junk yard at this moment.

dan

Try another gauge before you you give up.

The pressure jumping high and low does not seem consistent with internal problems.

Don't give up!

I dont think 17 lbs at idle is too low to worry about. What oil weight is in it, and was it fully warm? Jumping around is likley the signal to the gauge.

When the engine stumbles if the rpm goes lower than idle I'd expect the pressure to get lower too. Whatever caused the stumble is probly the issue.

[This message has been edited by 2.5 (edited 06-17-2014).]

ok I know I said I was going to take a break but I couldn't. Got to thinking maybe I ran out of gas, only had about a gallon in her for a year now, so when I got home I disconnected the line and turned key and fuel flowed freely. Told wife start it, would rather drive than push back into garage, she fired up at 3 lbs then after a second or two went to 16, got into to back it back in went down to 12, kept her running long enough to get on ramps and pressure stabalized at 20. Minumum pressure required is 15 lbs at 1100 rpm idle. Wieght of oil is 5w30 synthetic. My plans are to drain the oil, replace filter, even though i just did 2 weeks ago, refill with 10w40 conventional, double check wiring at switch, maybe drop pan and check pump. just and update

dan

Sounds like that thing needs a full tank and a long drive.

quote Originally posted by 2.5: Sounds like that thing needs a full tank and a long drive.

I agree, just don't want to get stranded in the middle of no where, thats why the stress testing in driveway, to catch possible issues.

dan

Take a chase car out with you and some radios in case they see anything amiss. Good luck with finding the issue.

quote Originally posted by bonaduce: I agree, just don't want to get stranded in the middle of no where, thats why the stress testing in driveway, to catch possible issues. dan

Pull a Ferris Buller, Put it on jack stands and a rock on the gas pedal, just make sure you block both the frt wheels, both sides and let her rip !

Steve

------------------
Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

[This message has been edited by 84fiero123 (edited 06-19-2014).]

Ok update, Was able to drop the oil pan after about 2 hours of trying not to remove an engine mount and breaking the level sensor (don't need it anyway). Found some sludge in the bottom of the pan, not much but some. Also found 3 small (1/8 x 1/16 x real thin) piecies of cast metal, no shavings. Checked all around and didn't see anything chipped or broken. Figured I would install a new oil pump as long as I was this far. Attempted to remove a bearing cap, just to check them, but since I am no longer fat I have no strength when laying on the garage floor. So I put it all back together, filled with 10w40 and started it, it has oil pressure again. Idle=19-20, slight throttle jumps to 30-35. So hopefully It was the original oil pump causing the issue

dan

GM says min. oil pressure at idle (1K) is about 20psi

I soft of like it when I don't have a guage, that way I don't worry about it.

My truck says "L -- H"

[This message has been edited by jaskispyder (edited 07-08-2014).]

quote Originally posted by bonaduce: Attempted to remove a bearing cap, just to check them, but since I am no longer fat I have no strength when laying on the garage floor. dan

I didn't know it worked like that!


Good to hear your oil pressure is better.