oil pressure drop!!

[72BLUZ]

i posted this on the 88 to 98 site, but i am hoping that maybe somebody here as well may have a little insite:
i have a 92 chevy with a 350 engine. the oil pressure has always pegged the gauge at start up and dropped to about 35 to 45 psi when driving down the road. last night coming home from work i pulled up to a red light and when the engine idled down the check gauges light came on. i checked and found the oil pressure fell to the red line. i stopped and checked the oil level. all was fine, nothing out of the ordinary. i shined a flash light on the sensor located behind the distibutor and saw it was oil soaked. i thought thats why, the sensor has gone bad. this morning i bought a new sensor and replaced it. but still having the same problem. i am going to change the oil and filter tomorrow due to the fact its oil change time. i am hoping maybe the filter is trying to collapse.
short of maybe trying a manual gauge to verify the problem. does any one know of anything else that may be causeing this, or had this problem with their engines.
my engine has about 36,000 miles on it since the over haul. then a new pump was installed. this problem just started. there have not been any other problems and there is no engine noise such as bearings rattling etc.


"i attached a manual gauge today and found i have a faulty gauge in the dash!!"

[Longhorn Man]

the pick up tube coulda fallen off the pump.

[rlb67]

I would try the manual gage. I don't trust electronics to give accurate readings. If no pressure with manual gage, may have twisted the pump driveshaft into. Pull the distributor and look down through the hole and see if you see anything out of the ordinary. Other than that, I would be pulling the pan quick!

[JMac11]

Using Fram Filters? Fram filters ALWAYS read lower on my vehicles

[Scott68-93-97]

Originally Posted by Longhorn Man

the pick up tube coulda fallen off the pump.

This happened to my diesel but it regained oil pressure after I stopped. With the pick up tube off it lost pressure when I hit the brakes. $8 for a gasket, a little welding wire so it doesn't happen again and 2hrs to put the 4x4 crap in and out to drop the pan and she's been fine since.

But I don't think that is your problem if its not reading at all, my guess is that it sounds like a bad gauge.

Put a motor in my toyota didn't read any pressure but I pulled it from a running perfectly good truck and had good oil psi showing with a manual gauges, and I put a new sending unit on it also, and nothing changed so I knew it was the gauge. Been driving it 2 weeks and it hasn't started knocking yet

[EyeH8the24]

my 94 would do that ..drove it three years that way ,sold it 2 years ago...guy is still drivingthe same motor in it ...it had way over 200k on it when i sold it

[72BLUZ]

thanks for all the info! i attached a manual gauge today at the shop where i work. it showed all is ok. i have a faulty gauge. i called the chevy dealer and they want $300. 00 for a new cluster and a core charge would be charged if i didnt bring in the old one. turns out that they set the new speedo to the exact mileage on the old one.
so now i am going to install a manual gauge under the dash as a backup!!

[Boog]

Chuck somewhere I have info pertaining to upgrading the early style gauge cluster to the 94 or so. If you think you might be interested in it I will see if I can run it down.

[Scott68-93-97]

Is the 92 manual speedo gauges still my 93 is electronic

Good to hear thats the case

[rlb67]

Originally Posted by Scott68-93-97

Is the 92 manual speedo gauges still my 93 is electronic

Good to hear thats the case

All C/K trucks 88 and on (no vent windows) had electronic speedo gauges. I'm not sure if the R/V style trucks had speedometer cables or not.

[72BLUZ]

Originally Posted by rlb67

All C/K trucks 88 and on (no vent windows) had electronic speedo gauges. I'm not sure if the R/V style trucks had speedometer cables or not.

i know the 88 for sure can change just the gauge needed. but the 92 has to change the intire cluster

[Shyguy]

I have a '92 GMC 3500 with a 454 and one day the oil pressure dropped to zero no matter what rpm the engine was running.

I checked the oil level and it was ok, the engine did not sound like it had low oil pressure.

I replaced the sending unit and the gage started working again.

Danny - Southeast Missouri

[72BLUZ]

Originally Posted by Shyguy

I have a '92 GMC 3500 with a 454 and one day the oil pressure dropped to zero no matter what rpm the engine was running.

I checked the oil level and it was ok, the engine did not sound like it had low oil pressure.

I replaced the sending unit and the gage started working again.

Danny - Southeast Missouri

i replaced the sending unit, but still shows low oil pressure