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Join Date: Feb 2003
Location: Mt. Lebanon, PA (Pittsburgh)
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84 911 oil pressure guage
My oil pressure guage has become very erratic. It will drop to 2 at a red light then suddenly peg all the way up to 5. While driving the guage is bouncing between 3-5 then remains pegged at 5, Whats up?
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Kevin 84 911 Carrera 71 911E Vintage Race Car 25 Ford Explorer ST 20 Subaru Crosstrek |
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07-29-2003, 02:10 PM
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Back in the saddle again
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Location: Central TX west of Houston
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My guess would be a bad connection.
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Steve '08 Boxster RS60 Spyder #0099/1960 - never named a car before, but this is Charlotte. '88 targa  SOLD 2004 - gone but not forgotten
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07-29-2003, 02:12 PM
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Location: Las Cruces, NM
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I second that, check the connection at the oil pressure sensor which i think is the one at the front of the motor. Look like a small cylindrical box.
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2007 Mazda 3 hatch 1972 Porsche 914 roller with plenty of holes to fix 
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07-29-2003, 02:14 PM
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Back in the saddle again
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yep, it's sticking straight up just to the right of the fan as you face the fan. It's about 1" across and 2-3" long.
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Steve '08 Boxster RS60 Spyder #0099/1960 - never named a car before, but this is Charlotte. '88 targa SOLD 2004 - gone but not forgotten
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07-29-2003, 02:18 PM
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Actually, the analog guage is toward the back near the fan side of the engine, on the right hand side, connected with a single wire that slides on the cylindrical thing immediately to the lower right of the fan housing.
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Porsche 2005 GT3, 2006 997S with bore-scoring Exotic: Ferrari F360F1 TDF, Ferrari 328 GTS Disposable Car: BMW 530xiT, 2008 Mini Cooper S Two-wheel art: Ducati 907IE, Ducati 851 |
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07-29-2003, 02:18 PM
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Take a toothbrush and some vinegar and give the connection a scrub.
Most likely however the sender itself has gone bust. Mine is doing the same thing, and cleaning the connection has not repaired it. $75 for a new one. -BG
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07-29-2003, 03:51 PM
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Mine's doing the same thing as well. After hearing that you can crack the housing while trying to unscrew the sending unit, I've decided that I'll read it as is and say I have great pressure above 2k rpm. (Between the idiot light, the temp and the level guage, I would think one would notice if there was a serious loss of oil). Must be a 1984 thing.
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07-29-2003, 08:00 PM
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I just replaced the sender on my 88 for the same kind of behavior (2 at idle, pegged at 5 while underway). Bit of a PITA to do it the right way, but I took John Walkers warning about possibly stripping the oil line threads/trashing the case seriously. You have to remove the AC compressor bracket to get a clean shot at removing the sender/mounting block which means pulling the muffler off to get to the 2 bottom bolts of the bracket. Glad I did it the hard way, tho, the sender was really wound tight on the mounting block and I can see how torqueing on it in the car could strip the oil line threads out of the case. The whole job took me an afternoon; freeing the muffler bolts and reconnecting the muffler straps were the hardest part. Be sure to replace the crush washers on the sender and mounting block when you are putting it back together.
Argo 88 Targa Last edited by Argo; 07-29-2003 at 09:09 PM.. |
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07-29-2003, 09:05 PM
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My '87 had the same gauge symptoms and it was a bad sending unit. I bought a crowsfoot socket for my ratchet/extension and it was a breeze. The socket fits under the housing. Sorry I don't remember the socket size. No need to remove anything else. That was two years ago and no problems since.
Good luck. Yeah, the $75 bites but it's nice to have an accurate gauge now. Bob
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Bob S. '87 911 ("Hardtop" per neighbor) |
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07-30-2003, 03:38 AM
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I too have seen the warnings (after I replaced mine). I believe it's a 27mm which works out to almost exactly 1 1/16" (conv to 26.9875mm). My craftsman crows foot fit like a glove. It was tight, but no damage.
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Steve '08 Boxster RS60 Spyder #0099/1960 - never named a car before, but this is Charlotte. '88 targa SOLD 2004 - gone but not forgotten
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07-30-2003, 04:31 AM
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It could be a simple cracked line at the top connection (the black piece) mine had the same symtoms until I re-soldered it. It works fine now.
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07-30-2003, 06:47 AM
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John Brandt, You were right! As I was diagnosing the problem the wire fell out of the black connecter which attaches to the sender unit. Unfortunately I was unable to re-solder it because it broke off down inside the connector. It must have been making intermitten contact and giving the erratic readings. I soldered on a new terminal and covered it with shrink tubing. Problem solved it works good as new. Thanks to everyone for your input and suggestions!!
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Kevin 84 911 Carrera 71 911E Vintage Race Car 25 Ford Explorer ST 20 Subaru Crosstrek |
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07-30-2003, 12:41 PM
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