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Removing Oil Pressure Sensor In 8.1l Suburban


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#1 mw442

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Posted 28 December 2010 - 02:38 PM

Ok it is nearly impossible to get your hands in there has anyone actually done this? I can feel it, and I can feel the clip for the connector, but I am really nervous about pulling the connector off as I dont think I can get it back on again there is no way to see and really hard to feel whats going on. Looking at picture of the small block sensor it is way easier because its so long this thing is short and stubby and the fuel lines run right over it. I just wonder about removing the drivers motor mount bolt and the motor might possibly go down a inch or so.

If anyone has actually done one of these in a 8.1l I would like to hear about it!

#2 snake428

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Posted 28 December 2010 - 10:02 PM

Acctually just put one of these in 2 days ago at work they are possible just drop a sending unit socket down with and extension on it. Not as bad as it seems to do the plug you will have to lay on top of the truck and hug the motor and barely reach it but it is not allways easy but that is not as bad as you would expect.

#3 tim73

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Posted 31 December 2010 - 01:45 PM

My oil pressure gauge the other day, when first started, went from pegged...to dead. Initially, I thought it was the gauge cluster...now not so sure...after seeing a few people replacing the sending units on these 8.1's. How did you guys know it was the sending unit and not the cluster?

#4 snake428

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Posted 31 December 2010 - 03:07 PM

Using a Snap-On Modis you can do a gauge sweep and see if it is good and look in the computer to see if it is reading any oil pressure or not.

#5 mwitte

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Posted 01 January 2011 - 07:40 PM

Looks like if you remove the oil pressure connector, the gauge should read 80. Plugging back in should be 0. If that checks ok then it's the sender. I know I have pressure as the truck would not remain running if the low oil pressure switch(built into sensor) detected no oil pressure. I am going to try and get a digital camera and get a picture back ther to see what it looks like

#6 snake428

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Posted 01 January 2011 - 11:21 PM

If you unplug it on the truck the gauge will not move it will not affect the gauge.

#7 mwitte

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Posted 05 January 2011 - 11:02 AM

I found the pin outs for the gauge cluster and found that the oil pressure sensor goes to pin 1 Brown/white. Disconnected connector from gauge cluster, and measured resistance to ground on pin 1. Resistance very high. Started truck and resistance went to 500 ohms and varies with engine speed. Looks like the sensor is ok, probably the oil pressure stepper motor apperently a lot of people have gauge issues with those. Seen them on ebay for llike 7 bucks and looks pretty easy to change found a instruction on the web. I'll let ya know when I get it in.

#8 mwitte

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Posted 06 January 2011 - 04:51 PM

So the pinouts that i found on the web were wrong, my truck uses serial data from the PCM to drive the oil pressure gauge.I back probed the correct pin on the PCM and it had 5V on it, and no continuity to ground so eith the senor is bad or the the ground to the sensor is open. Since this just went i am going with the sensor. I got the sensor and socket and I was able to get to it but it is so frickin tight I am afraid I am going to snap it off as its brass. If that thing snaps I am dead...

Definetly sucks to get to.

Tim73, after the connector is disconnected the guage will go to 80 and back down again when first started. Maybe you connector is loose.

givin up for now its getting too dark. At least the truck runs I was afraid it had the low oil pressure switch in it but that doesnt appear to be the case.

#9 snake428

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Posted 06 January 2011 - 07:38 PM

You need to spend more time just putting in the sending unit and not so much time on here then your truck would be fixed.

#10 mwitte

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Posted 06 January 2011 - 11:01 PM

LOL!!

I have been putting it off hoping it would be something else. I have popeye fore arms and they just dont fit in there. Trust me if it was even a little easier it would have been done long ago.

what I am facing now is that the sockets brand new and its a really tight fit on the replacement and since its not a normal shped socket I cant quite get it on good to the old sender. I have it on and I put some torque on it and its slipping off defenitly dont want to round it. My last effort I had it on good and it wouldnt budge. I have broke many things off in the past and this being brass makes me a little more careful. If it breaks its a huge problem to say the least.

#11 snake428

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Posted 07 January 2011 - 08:05 AM

Not that it can not be broke but those are not brass they are aluminum at least the original ones are.

#12 mwitte

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Posted 07 January 2011 - 05:28 PM

So try as i might I could not get the oil pressure socket to fit its just a little too tight and kept slipping. I went and go another looser socket and got it on quite easily. Very tight but got it to budge and got the sensor out. I looked at it and you could see where it was getting ready to sheer off I'll have to post a pic what a pucker factor. I took about 5 mintues to get it off really not bad as you said.

However I spent the last 2+ hours trying to get the new one in I just cannot get it to start. I can get my hand in and feel the hole and guide the sensor down on the socket and extension. I even screwed the old and new ones into a oil pressure adapter I have thats the same thread so I know the threads are ok. The part is a AC delco and I cross referenced its fine. The biggest issue I am having is that the fuel lines run over there and there is a big fat harness right over where it has to go. From pictures of the motor it appears to go in straight I had a swivel on it so I couldnt tell.

Is it a straight shot to start or is it at an angle. If at a angle which way? I might have to pull the drivers valve cover to get my arm in there better.

Gave up for tonight its like 39 and started to rain.


BTW mine was brass and I am pretty sure its all original.
ThnX

#13 snake428

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Posted 07 January 2011 - 08:45 PM

Should be straight up and down good luck that can be the hardest part once you get it started all smooth sailing from there

#14 mwitte

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Posted 07 January 2011 - 10:26 PM

thnx thought it was looks that way from pics. Why on earth would they put something like that in a location like that? I couldn't even think about the crankshaft sensor I have read a couple of horror stories about them not coming out. When you did it did you feel for the hole with your right hand and work the extension and sensor with the left? Seems the only way. If the fuel lines and that harness werent there would be a snap I think the harness is getting me as it seems to be right over it.

#15 mwitte

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Posted 08 January 2011 - 02:41 PM

2 more hours of trying to start it. My hands and arms are all cut up. Took the valve cover off helped a little. Really at my wits end here.




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