Pinned Oil pressure Gauge (Page 3/3)
fierofool OCT 12, 12:54 PM
Johnny, tightening or loosening on the plastic nut will break the unit. Usually twisting the terminals loose from their internal connections. I can't understand why they made it with a hex case unless it was so someone would use that, resulting in the sale of another sending unit.

Isn't the center lead the constant 12 volt lead? If it is, grounding it should result in blowing something or burning something.

If a conversion to the 88 sending unit is done, steps need to be taken to prevent water from getting into the top. My conversion shorted out with the first rainfall, killing my battery. My initial solution was to put a piece of large wire harness sheathing over it. The best method is to get a brass street elbow and install the sender horizontally instead of vertically.
olejoedad OCT 12, 02:04 PM
The center lead has 12vdc applied through one of the coils in the Gage, the 'sending' unit provides a variable resistance (to ground), which varies the voltage across the coil, causing the needle on the gage to deflect.

Grounding the wire will not blow a fuse because the coil acts as the load on the circuit.

The 88 oil pressure sending unit faces straight up, has no problems with water intrusion when the WeatherPak is installed properly. A little silicone lube on the ribbed seal may be applied for added water resistance.

Perhaps your connector didn't seal properly, causing your battery drain problem.
fierofool OCT 12, 09:26 PM
The weather pak connector I got would actually let water enter along the wiring, even though it had the rubber seal. These are the part numbers from Rock Auto that I used.
Oil pressure sensor. Rock Auto Part Number AC Delco D1808A.
Oil pressure sensor harness connector. Rock Auto Part Number AC Delco PT121.

When I replaced it, I put the sheathing over it and also packed the top end with dielectric grease.
pmbrunelle MAY 03, 12:05 AM
My oil pressure gauge is starting to dance a bit again; I'm suspecting the 88 sender catching rain from the decklid vent. My sender is pointing straight up, with the connector up top.

Last time I packed the sender's connector cavity with dielectric grease, until it oozed out from everywhere when I plugged in the connector.

I'm on my second Standard PS245, and not the AC Delco D1808A. Would AC Delco be better?

Also I'm running 15W-40 oil. When the senders are new, the needle points to 80 psi with any revs, so I don't know if high oil pressure could be damaging the senders.

I'm not sure if it's time to make a protective cap...
fierofool MAY 03, 09:48 AM
The top of the early sending units had a pressure relief button on the top of them. This could allow water to get inside the inner workings and short the sender. When I changed over to the new style sending unit, I had a similar problem in that the terminals in the harness aren't waterproof. Water again shorted the sender. My solution was to obtain a brass street elbow 90-degree fitting to screw into the sending tube. Now, my 88 style sending unit is horizontal and no water can get into the terminals.

As far as AC Delco over Standard, I personally go with Standard Ignition after buying an AC Delco and finding a BWD box inside with the sender in it. Echlin fro NAPA is also a good choice.

Something that should be done on maybe a yearly basis is to attach a mechanical oil gauge to the sending tube and get a reading at operating temperature while the engine is idling. Then you have something to compare your in-car gauge to.

[This message has been edited by fierofool (edited 05-03-2021).]

theogre MAY 03, 11:51 AM

quote
Originally posted by pmbrunelle:

My oil pressure gauge is starting to dance a bit again; I'm suspecting the 88 sender catching rain from the decklid vent. My sender is pointing straight up, with the connector up top.

Last time I packed the sender's connector cavity with dielectric grease, until it oozed out from everywhere when I plugged in the connector.

I'm on my second Standard PS245, and not the AC Delco D1808A. Would AC Delco be better?

Also I'm running 15W-40 oil. When the senders are new, the needle points to 80 psi with any revs, so I don't know if high oil pressure could be damaging the senders.

I'm not sure if it's time to make a protective cap...

Heavy Oil can wreck an engine. Even on old engine w/o variably valve and other things that Hate this. More so driving in Cold Weather. read OM, my cave Oil and Filter or use api.org for charts of oil vs weather temp

Never trust a dash gauge. Use a real gauge. More so on V6 w/ known oil problems and 88+ "Dukes" w/ balancers.
High reading can be anything wrong w/ dash wiring, real problem w/ engine, or both.

Si grease is likely still keeping water out.
Did you grease the plug w/ back seal out? No? Then back of plug likely hold water and rot on V6 w/ AC because still soak the back when water get in thru the vents.
pmbrunelle MAY 04, 12:09 PM
I left the cable seal in place, though I did see dielectric grease ooze out of the gap between the cable seal and the wires.

I think I'll be most likely making a protective cap.
fierofool MAY 04, 04:20 PM
A car that Georgia Fieros acquired to restore for a disabled vet had the 88 harness end inserted through the top section of a water bottle then filled with silicone RTV.
weatherstud SEP 27, 10:54 PM
I have read up and down this thread, but my issue seems to be a bit unique.

I swapped an 84 duke in my 86 that had a duke that went to that engine bay in the sky.

So now I have '86 wiring in the car going to an 84 motor. Should not be an issue, as its the same basic motor, except the 84 had a different oil sending unit. Sill three spades, but significantly smaller.

My oil gauge goes to "0" when I turn the key on (not started), and then pegs when starting and running.

Motor has a brand new '84 style sending unit, and just to make sure I was covering basis, installed a new tach/oil gauge combo. So both are good

Only thing left is wiring (or connector), which I assume it where the problem is...but have no idea how to get around it.

I welcome any suggestions.
cartercarbaficionado SEP 28, 02:41 AM

quote
Originally posted by weatherstud:

I have read up and down this thread, but my issue seems to be a bit unique.

I swapped an 84 duke in my 86 that had a duke that went to that engine bay in the sky.

So now I have '86 wiring in the car going to an 84 motor. Should not be an issue, as its the same basic motor, except the 84 had a different oil sending unit. Sill three spades, but significantly smaller.

My oil gauge goes to "0" when I turn the key on (not started), and then pegs when starting and running.

Motor has a brand new '84 style sending unit, and just to make sure I was covering basis, installed a new tach/oil gauge combo. So both are good

Only thing left is wiring (or connector), which I assume it where the problem is...but have no idea how to get around it.

I welcome any suggestions.


a. why not start a new thread to be a little less messy.
B. the "smaller" sending unit is an idiot light one. use an 86 one. same thread same everything but is actually for giving a reading