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73-87 Chevy _ GMC Trucks => Interior & Equipment => Instrumentation => Topic started by: kbw87 on January 31, 2010, 11:38:21 pm

Title: oil pressure gauge not working
Post by: kbw87 on January 31, 2010, 11:38:21 pm
I've got an 87' with an oil pressure gauge that is pegged all the way to the right.  Does anyone know if this is a sensor issue or gauge? 



Thanks
Title: Re: oil pressure gauge not working
Post by: 4x4HighSierra on January 31, 2010, 11:50:37 pm
Most likely the sending unit behind the distributor on the drivers side has gone bad.  Or it has come unplugged and is grounding itself out causing the gauge to peg itself.
Title: Re: oil pressure gauge not working
Post by: Irish_Alley on February 01, 2010, 03:54:52 am
does it do this with the key on or off? if it stays pegged out it would be the gauge if it does this when you turn the key on it should be the sending unit
Title: Re: oil pressure gauge not working
Post by: ohio hab on February 01, 2010, 05:53:44 pm
I once  had this problem on my 84 C-10, and the problem was caused by dirt, sludge, in the sending unit.
Title: Re: oil pressure gauge not working
Post by: VileZambonie on February 01, 2010, 06:13:02 pm
check the connection at the sending unit first.
Title: Re: oil pressure gauge not working
Post by: kbw87 on February 01, 2010, 07:29:36 pm
I was assuming the sending unit was the sensor that threads directly into the block.  I did pull this wire and check the connection to and no luck. 

The gauge stays pegged to the right key on/key off.

I haven't pulled the dash panel off yet to check anything with the gauge yet.  Maybe i'll pull the gauge then.
Title: Re: oil pressure gauge not working
Post by: VileZambonie on February 01, 2010, 11:45:44 pm
Did you check the oil pressure switch or the oil pressure sending unit?
Title: Re: oil pressure gauge not working
Post by: Irish_Alley on February 02, 2010, 04:47:04 am
going with vile it almost sounds like you just said you tested the switch on the side of the block the sending unit is in the intake manifold behind the distributor
Title: Re: oil pressure gauge not working
Post by: 78 Chevyrado on February 02, 2010, 02:34:57 pm
I broke the connector on my sending unit while doing a tune up.  it stays pegged all the way to the right at about 2:00.  I'd get a new sender.

an 87 has 2 oil psi sensors.  It's the big soup can looking one by the oil filter is for the gauge.  On the older trucks the big can shaped one is up by the intake.

(http://i160.photobucket.com/albums/t195/wes2880/87%20R10%20Stuff/Fresh400ciSB003.jpg)

Title: Re: oil pressure gauge not working
Post by: kbw87 on February 02, 2010, 07:53:15 pm
Good pic - great info.

I didn't realize there was 2 sensors.  I had only been looking by the exhaust manifold.  My gauge is in that 2:00 position as well.  I will check the connection first thing tomorrow and start there.  

Thanks for the help guys.
Title: Re: oil pressure gauge not working
Post by: Layne on February 02, 2010, 08:09:06 pm
Don't mean to butt in here, but which one would you hook up a mechanical guage to? IE Autometer?
Title: Re: oil pressure gauge not working
Post by: VileZambonie on February 02, 2010, 11:40:15 pm
A mechanical gauge would require you to run a direct line from any oil gallery tap.
Title: Re: oil pressure gauge not working
Post by: Irish_Alley on February 03, 2010, 01:50:45 am
most time with mechanical gauge people just remove the sending unit but the distr. and replace it with the hose and fittings the gauge comes with
Title: Re: oil pressure gauge not working
Post by: Layne on February 03, 2010, 03:50:33 pm
I TEE'd into the one on the citation. Figured I'd do that. but didn't know which one would be better or if I can just remove one or the other and tap in...
Title: Re: oil pressure gauge not working
Post by: frito-bandito on February 03, 2010, 06:23:42 pm
Don't mean to butt in here, but which one would you hook up a mechanical guage to? IE Autometer?


I always hook up mechanical oil gauges to the one by the distributor just because its closest to the firewall, but furthest away from exhaust manifolds or steering shafts.
Title: Re: oil pressure gauge not working
Post by: ilovebeingme87 on January 06, 2011, 02:44:11 pm
I have the same problem with mine!  I replaced the unit by the distributer.  The one by exhaust manifold is disconnected and I do not know where to reconnect anyone have a wiring diagram?  I started pulling the dash cluster last night but if I dont have to even go that route I would prefer(old plastic).  Although plastic Epoxy sure is great..lol
Title: Re: oil pressure gauge not working
Post by: Irish_Alley on January 07, 2011, 03:32:18 pm
What gauges do you have. Stock or after market
Title: Re: oil pressure gauge not working
Post by: ilovebeingme87 on January 07, 2011, 03:55:48 pm
Stock.  I figured it out.  The tan wire was disconnected from the oil sender by the passenger side manifold.  I pulled the dash to see what wire were to what.  The tan wire was severed behind the distributor.  Ordered the wire last night and will install next week.  While I was at it I noticed most of the bulbs were blown so I ordered the 168 led's in blue these leds have 5 diodes on them so it should look pretty slick.  Ill post a pick when I have it all operating correctly.  Now I just have to figure out why my high beams are not working.  I thought the switch for them was on the floor board but it isnt, and the wand on the left side of the steering wheel has alot of play towards the dash and back, so I suspect thats my culprit.   
Title: Re: oil pressure gauge not working
Post by: tx5.7travel on January 15, 2011, 09:36:55 pm
I have the same problem on my 84 with a stock gauge but I already replaced the unit and have the same results? Any suggestions?
Title: Re: oil pressure gauge not working
Post by: Irish_Alley on January 16, 2011, 08:45:09 am
Could be wires on the circuit board or the gauge. take the dash apart inspect the circuit board if no problems replace gauge
Title: Re: oil pressure gauge not working
Post by: tx5.7travel on January 17, 2011, 09:05:15 pm
I had to replace the gauge cluster and I remember the circuit board being good, no problems to the eye! It will peg out the gauge every time you connect it to the sending unit, the circuit is ok and the sensor is new so I am guessing the gauge could be faulty?
Title: Re: oil pressure gauge not working
Post by: ToddN on January 18, 2011, 06:37:36 am
Just to clarify for lurkers having issues, the sender is in the block.  The sensor is behind the distributor.  I see people getting them crossed all the time when asking questions, thinking they are the same part.
Title: Re: oil pressure gauge not working
Post by: ToddN on January 18, 2011, 06:39:55 am
I'm not saying you guys were, I'm just saying .  I did it when I first started tinkering. ;D
Title: Re: oil pressure gauge not working
Post by: ToddN on January 18, 2011, 06:43:40 am
Hold on, nevermind.  I havent had coffee.  I was thinking about coolant.  I'll shut up now. ::)
Title: Re: oil pressure gauge not working
Post by: VileZambonie on January 18, 2011, 07:45:15 pm
I had to replace the gauge cluster and I remember the circuit board being good, no problems to the eye! It will peg out the gauge every time you connect it to the sending unit, the circuit is ok and the sensor is new so I am guessing the gauge could be faulty?

Are you connecting to an oil pressure sending unit or oil pressure switch? Try another sending unit.
Title: Re: oil pressure gauge not working
Post by: ToddN on January 19, 2011, 06:28:58 am
Ditto.  Thats what I was trying to say :D
Title: oil pressure gauge not working
Post by: Lowhoe775 on August 08, 2013, 09:16:53 pm
Change out the sending unit, happened to mine now it's working fine. When you take it of shake it if u hear anything loose its bad. When putting on the new one don't over tight.
Title: Re: oil pressure gauge not working
Post by: Irish_Alley on August 08, 2013, 11:19:41 pm
lol i forgot about this post since its three years old, but good to know if anyone else has this problem