Oil sensor located under the filer???

[turbov6joe]

What does the electrical sensor that is located under the filter and part of the filter/cooler assembly do and how exactly does it function? I'm having a hard time getting my motor to fire when cold....it takes a bunch of cranking before it finally comes to life. Once running and the plugs clean up it runs great. This probem doesn't seem to happen when the motor is warm. My guess is that the sensor is a low oil pressure sensor and is malfunctioning not letting the motor fire when cold. I also noticed that this sensor is leaking, I wonder if this has anything to do with the firing problem???

 

[Jan Larsson]

That is the oil pressure sensor, not sure what impact it would have if it's leaking more than making a mess

You can get a new one from GM ##10096199 GR 1.800 Sensor, Fuel Pump Engine Oil Pressure


Just got one myself as I will change it when I detail my engine bay (looks like mine is leaking as well

 

[src76ta]

This sensor does two things. One purpose is to send the oil pressure reading to the gauge in the instrament cluster. The other purpose is to allow the car to start and run if the fuel pump relay goes bad. When oil pressure at that sensor reaches 4psi it powers the fuel pump. If your car only starts after long cranking you may want to check the fuel pump relay located on the firewall on the driver's side of the engine compartment. This relay sticks out farther than the other two.

 

[turbov6joe]

Thanks for the info, I had a feeling that it had something to do with starting/running. My feelings are that the thing is leaking pressure hence why the car won't start right away. I'll check my FP gauge and see if the pump is comming on as soon as I turn the key....that should tell me something. I have a sneaky feeling that this thing is also where my massive oil leak is comming from under MID-WOT conditions. It's leaking bad enough the oil is running back on to the crossover pipe and blue smoke is trailing the car at speed. Oil seems to be dripping from the cross member, on to the oil pan, then back to the pipe. I've replaced my oil pan gasket once already thinking it was that....NOT! I'm ripping my hair out trying to find the leak....I HATE LEAKS!!

 

[chicagoTTA]

Although it won't tell you what pressure you're at, you'll ABSOLUTELY be able to hear the FP run (for about 2 sec) after you turn the key.

If you don't hear that humming noise, you've got bigger fish to fry.

Fried fish? Nasty.

 

[src76ta]

I have a low mile car also and I get some oil from the rear main seal when the car sits. The oil falls onto the crossover pipe and burns off. You may be pushing some oil out the rear main seal. These cars are known for leaking in that area.

 

[turbov6joe]

I know 99.9% for sure that the rear main is NOT leaking. With the converter dust cover off and a bright flashlight I can see that the rear main cap is dry. The oil is dripping down from the front of the motor, on to the the cross member, then blowing back to the cross over at speed and burning off.

Riddle me this batmen. I had a feeling that the oil filter was leaking at the seal. So I picked up a new PF1218 and put it on today. All of the sudden the problems with starting are gone...coincidence or related??? The pressure switch is still leaking a drop now and again, but is going to be replaced this week anyhow. I started and restarted the car numerous times and it fired almost immediately! The best I can tell thus far is that my oil filter is possibly the cause of the oil leak problem. It looks as though the filter was spraying out the bottom and on to the cross member and back. The cross member is very wet on top, that's why I think this might be my problem. Although every other time since this leak reared its head, the car would not leak a drop untill driven....almost like it wouldn't leak untill the very higher end of the rpm range (WOT). I reved the motor up quite a bit in idle and din't see any new oil, so maybe I fixed it.

 

[src76ta]

Some times it's better to be lucky than good.

 

[turbov6joe]

It was wishfull thinking that the oil leak was the filter. I took the car out today and it was leaking like a whore while under boost. I reved the motor up to 10,000 rpm in the garage and not so much as a drop. Go out and get after it and wha-la...blue smoke as fas as the eye can see

I did spray everything down with brake clean before heading out and it appears that the POS Felpro pan gasket very well could be the culprit! Now I'll have to jack the motor up off the mounts again and change that fricker out with a Cometic cork gasket...what a PITA!!

 

[FastTurb]

hi did you ever find that leak? we have a leak only under motion in the front too. clean it off and run car for hours - no leak. take it for a spin and oil wet on the brace under the filter. replaced the oil sending unit. wondering if we are getting leaks through the front cover but can't see any cracks and of course why only when driving?? I'm not sure what a front main seal leak looks like but it just seems too high but it could be getting flung too. yeah I sure hate having these type of problems.

 

[turbov6joe]

After chasing that bastard for a month or more my pop and I fingered it out......it was the front cover. Long story short, I used an extra front cover gasket that was in my "loose/unused gasket" box that turned out to be for another application. It fit just right everywhere but at the lowest most point of the cover on the passenger side. It was allowing oil to be slung out onto the oil filter assembly and all over that side of the motor. I spent 6.5 hours replacing that mistake....and to think I used that loose gasket so I could return the unopened gasket set and save $20??? With my leak you couldn't tell where it was coming from untill I removed the IC bracket on that side and had my pop rev it up a bunch while I watched it from under the car....very obvious then!

 

[FastTurb]

OK Joe,

Yes that's what I am afaid of - the leak in the cover or gasket. then when I pull the cover is it time to do the timing chain and then why not upgrade those stock valve springs, take care of the first-start-of-day knock on the bottom end, and on and on.

a looonnng weekend coming up I guesss. thanks for the update.

 

[83ttypecooled]

leaks

Hi!
Front seal and oil pump gasket come to mind. Let's see, what else is down there... Oh the oil cooler seal. that's a good possibility...As you know, a different cooler is used on these motors.
Dale