Oil pressure switch revisited

[turbovair]

My oil pressure switch is starting to fail(123,000 on original sender). Gauge needle is starting to jump erratically and read about 20 lbs higher than normal. I'm going to the dealer this morning to pick up a new one. Does anyone recall the socket size Ill need to replace it? I am unable to locate it in the threads.
Thanx,
TVair

[RCF]

1&1/16 deep socket. Bought mine from PepBoys. Is labeled as oil sender special tool. About $8.00 as I recall. 3/8 universal is also handy to have. smile.gif

[turbovair]

Thanx RCF

[curmudge1]

Can you post the OPS GM part number, please? I seem to have misplaced it. Thanks.

[RCF]

#12555492

[ol9465er]

Changed my Lift Pump yesterday and works fine with 12V applied to terminal G of DTC connector, lots of fuel from water drain. However, opening water drain when running, no fuel of hose and truck started to die.

Checked voltage at terminal G and only 8.5V when running - doesn't seem normal (is this ok place to check for voltage?). Will check volts at pump now.

Now suspecting OPS or wiring. Any other
suggestions?

Am doing all this account stalling seriously in last couple weeks - working my way down to PMD or IP. Have check and cleaned grounds also.

Thanks in advance.

Bill
ol9465er
Stock 94 3/4 Chev 4x4 LWB Ext Cab
279000 KM (174300 Miles)

[MTTwister]

Hey ol9465.... The OPS has a light-wieght set of points ( maybe 1 amp) in it that carries a higher amperage ( maybe 3 amps) to the lift pump. Search on OPS Relay - install a "cheap and easy" relay to take the load off the ops points. From the sounds of it - the OPS may be giving you trouble... Good Luck!