Ugh...So tis is what happened

**ChevyZ76** · 05-08-2014, 09:34 AM

My friend and I went to replace the knock sensors on my 1998 Camaro Z28. We tried to extra car with the oil pressure sending unit in the back of the intake. Put everything back together and started the car. On start up there was a crackle noise that went away. We shut it down and started it up again heard the noise but it settled down. I revved it up and there was a loud pop then it sounded normal. But the car started leaking oil really bad, even when it was just sitting there. Then the oil pressure would not read. Not sure what we did but it does sound like the opsu is broke. But would the vehicle leak oil with this broke? Also noticed that behind the lock on the backside there was what looked like a pipe coming up from the bottom. We had nothing to attach to it and it felt like it had plastic covering it. Any ideas on whats going on.

***SMWS6TA*** · 05-08-2014, 09:40 AM

Yes, if you break the OPSU in the wrong spot it will blow oil all down the backside of the engine. Just reach you hand back there and you'll feel it.

I can even tell you will almost 90% certainty that the hose form the back of the intake to the brake booster was the reason. It's easy to forget it's there and smack it.

You can try to pull it off without removing the intake but unless you have small hands and can do it blindly, taking the intake off again may be your only option.

**ChevyZ76** · 05-08-2014, 09:43 AM

Everyone says that the sensor is the oil pressure sending unit. But it looks to be the absolute manifold pressure sensor

**ChevyZ76** · 05-08-2014, 09:45 AM

I might have broke something and don't even know it

**ChevyZ76** · 05-08-2014, 09:53 AM

So I did break the unit. i was looking for pics on where it was. And it belonged in the pipe that I was speaking of

***SMWS6TA*** · 05-08-2014, 10:54 AM

looks like this? If so then yes that's the OPSU

**ChevyZ76** · 05-08-2014, 11:41 AM

Yup after checking that is what I broke. Had I known I would have not put it back together, lol. So when I felt it, it had like a plastic covering, hard to explain. Haw do I go about taking it off noe that is broke. Should a get the special tool. Or can I hand tighten it once I get it out. Thank you again. You have been very helpful.

***SMWS6TA*** · 05-08-2014, 11:50 AM

There's a $10 socket you can pick up from parts stores. The metal base is still in the block. You can use it to hand tighten it on and give a snuff fit. No need to gorilla tight it.

**ChevyZ76** · 05-08-2014, 11:53 AM

Ok, now I just need to find the unit. I didn't see it before I put everything back together. This really sucks, lol. I think that it must have gotten in between the booster hose that goes to the back of the intake. Then when we pulled it before removing the sensor it pulled it and broke it. Hopefully I'll be up and running tonight.

***SMWS6TA*** · 05-08-2014, 12:14 PM

yep...almost always happens that exact way.

**ChevyZ76** · 05-08-2014, 04:31 PM

Back up and running. Oil pressure is good and motor runs good. Cleared all the codes. Drove around for a bit and nothing has turned back on. Thank god. And thank you for all you help.