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FYI about oil pressure and sending unit problems

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Old Aug 31, 2006 | 07:17 AM
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Default FYI about oil pressure and sending unit problems

Figured I would post up my story of my sending unit failure nightmare.

A few weeks ago we got my forged 347 back into the car, and fired up. At first oil pressure was great, 60 lbs cold idle etc.... few days later we started the break in process of taking it up and down the road... mid to high rpm runs and letting it bring itself back down.

The first time we really nailed the car in first, I noticed oil pressure drop immediately 15-20 lbs. Great I thought... I just trashed a bearing.

Upon bringing it home.... I noticed it was running smooth as can be... no abnormal noises aside from a bit of lifter noise and the normal exhaust leaks. So I took it back out... car was idling as low as 25 lbs at hot idle, and wouldn't go over 40 lbs under WOT.

I just knew I trashed a bearing, or the machine shop I had used must have screwed the clearances or something similar.

FAst forward to the other night... friend of mine had a great idea of wiggling the sending unit with the car running to see if it made a difference. Upon just touching the sending unit the top half of it was "loose" the bottom of it was into the block fine but the plastic piece was loose as could be. And if you pushed it to grab a good connection, my oil pressure would shoot into thte 50 range at idle... and 65 ish under light throttle. So it appears to be a bad sending unit.

Going to advance today to pick up another one.

Made me feel 100x better however... considering I had never heard of a sending unit expressing those types of symptoms before. I was always under the assumption that it either worked, or was broke..


so if you have anything similar to this.... don't skimp out on replacing the sending unit.. its going to save me alot of heart ache.
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Old Aug 31, 2006 | 07:35 AM
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Whew.... I bet you were never so happy to find something broke!
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Old Aug 31, 2006 | 09:43 AM
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Originally Posted by mr2guru
Whew.... I bet you were never so happy to find something broke!

Yep. Very scary feeling knowing your 3k short block might be in danger of letting go.
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Old Aug 31, 2006 | 01:00 PM
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How much did the sending unit run you? Ive been needing to replace mine for a while now.
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Old Aug 31, 2006 | 01:55 PM
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Something similar to this happened in my GTP, I would go over bumps and my oil pressure would change while my RPM's didn't.

I contacted autometer and told them what was going on and they sent out a new sending unit really quickly. I changed it the next time I changed my oil and all has been well since.
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Old Aug 31, 2006 | 02:19 PM
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i broke mine when taking off my intake, only cost 37 bucks from the dealership. it does read higher than before but i hear thats normal.
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Old Aug 31, 2006 | 02:22 PM
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A lot of guys break them while taking off or putting on the intake. The trick is to reach back there and guide the large hose over it.
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Old Aug 31, 2006 | 03:23 PM
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Originally Posted by StevieZ
A lot of guys break them while taking off or putting on the intake. The trick is to reach back there and guide the large hose over it.
That or unplug the sensor and then pull the intake.
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Old Aug 31, 2006 | 06:41 PM
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Originally Posted by FBDYLVR
That or unplug the sensor and then pull the intake.
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