snksknr94

I had a new clutch installed yesterday, drove the car around the block a couple of times, took it all through the RPM's then drove home. Today I went to go for a drive for the first time since I drove home yesterday and noticed that at idle the oil pressure guage was reading right on the edge of the red, then when I gave it gas it would only move to about 1/2 way between the red and the first dash on the guage. I didn't even look at the oil pressure guage yesterday but, I have a feeling it was the same way. Could the guy who installed my clutch forgotten to plug something in, or maybe broke the sender, or something? I'm not real sure where the sending unit for oil pressure is located, but ithe pressure was fine before the clutch install. He installed the McLeod street twin and master cylinder, and also a new rear main seal. The car runs fine, and I would expect it to be knocking up a storm, or at least making some sort of noise if the oil pressure was really that low, especially after I romped on it last night. Anybody got any ideas?

Larnach

If there's no oil pressure I believe the ECU will cut the fuel.

snksknr94

Does the ECU pick up oil presure from some place else? The car runs great, no probs at all, but I'm kinda leary of driving it when the oil pressure guage barely move at WOT.

96ltz

Not sure on a '94 but '95-'96 were on back by the egr valve. I think '93 were down by the oil filter?
I'm sure you have but check your oil level and for leaks. Look at shoebox's page for pictures of the sending unit and check for damage/loose wiring. If none of that works hook up a mechanical gauge to verify the reading.

shoebox

If the wire for the sensor got pinched and grounded, then it would read low all the time. The sensor is located behind the intake manifold on the top of the block.

Unplug the connector from the sensor and turn the key ON. The gauge should read high pressure. If it does not, the sensor wire is grounded or the cluster has a problem. Most likely the wire in your case, since you just had work done in the vicinity.

I have read what the manual says about the relation of the pressure sensor to cutting off the fuel pump, but I have not yet been able to see how it is accomplished. There really is nothing in the wiring diagrams to support the function.

drop top steve

I believe your correct on this, some earlier GM's had the OP tied to the FP relay. I don't see this on either of my 97's or my old 96. I did locate what I believe to be a rollover switch, in the right rear wheelwell just below to roof panel. I believe it well cut power to the FP in the advent of a rollover.

shoebox

Then, I think the OP thing might have been a carry- over in the manual that they forgot to delete.

snksknr94

Thanks!! I'll try that in the morning. I just talked to one of my buddies who said he broke his oil pressure sender putting his tranny back in. I think that is the problem, I'll post back if it doesn't work.

snksknr94

Is this the same for 97 cars? My buddy has a 97 and he told me when he forgot to plug the sender back in it read low, not high.

treyZ28

i've lost ALL oil pressure-
car stayed alive

symptoms sound EXACTLY like when my pickup fell off.
ran up, got romped by the crank and shot down to the oil level sensor, cracked that, shot that into the oil pump and all that stuff was stuck in there.

all better now though

shoebox

Yes, it should act the same. It could be that the terminal end on your buddy's wire was touching to ground when it was off.

Bad T.A.R.A

Well I have been worried my oil pressure was low. So before going in having my engine rebuilt I replaced the oil pressure sensor behind the intake and my oil pressure is back up where it is suppose to be at 20 at idle. Feels better before it was right at the red line at idle.

Smokn '94 Z

If your car is still alive then you know it is the sending unit. I went to the track & noticed my OP was damn near bottomed out. I told my buddie that the car is still running strong so I decieded to still run it at the track. Got my best MPH's that day. When I got home I noticed the plastic end of the sending unit was basically hanging off the rest of the sending unit. I went with an Autometer OP gauge in it's place...

treyZ28

I ran my old motor without any oil

snksknr94

I just unplugged the sender, and the oil pressure guage read high. This means I'm not grounding out on anything, what else can I check? Also, where do I hook a mechanical guage to check it that way.