Well, daughter came home from taking her kids to school, and informed me the Oil Pressure light in the truck was coming on.... Took it for a ride, and sure as shick, it is. Thing is though, the gauge still reads 40 pounds of pressure. Gauge does seem to be working. Oil level is full... Light is very random, but, spends most of its time on, once the truck warms a bit. Gauge will read erratic on occasion, but, for the most part, does what I expect an oil pressure gauge to do.

Plenum has been repaired, oil pump is new. (high volume) Truck runs GREAT, and doesn't make any of the noises I would expect if oil pressure was indeed zero..... Anyone have a wiring diagram for the 96 model year? Or some semblance thereof? (pre-98 would be my guess.)

 

I can send you a wiring diagram tomorrow. I will have to scan it to my computer ,but can't get to the book tonight. Sounds like a bad sending switch to me

HeyYou,check out the update on the Leaf springs tread and look at the letter I got from them today

 

If you could do that I would greatly appreciate it. If you could, just upload it someplace like photobucket.

Thank you.

 

Will do

 

mine does get down to about 2 psi (machanical gauge) when at a warm idle, i assume its just worn internals. its something to the effect of what ur decribing: gauge reads 0 psi at warm idle, 40+ at cold startup, 30 while driving warm (light may be on). Ive been driving it like this for over a year to no ill effect. i honestly dont care if it seizes, all the more reason to kick it in to high gear on the 408 project

if u want to throw an inexpensive part at it, get a new sending unit. but checking pressure at warm idle with a mechanical gauge will tell the tale

does it always drop to zero at warm idle and then rise when you get on the go pedal, pressure gradually dropping as the engine warms? if thats the case you could try a thicker oil to cover it up for a while, atleast.

 

Actually, the behavior is REALLY weird.

At startup, cold, pressure reads approx 40 PSI, light off.
As engine warms, pressure stays about the same, light is intermittent.
Fully warmed. Light off at idle, pressure just above 40. Step on the gas even a LITTLE bit, lite comes on.
Gauge is REALLY random. It might plop down to zero for a second, and then, right back up to around 40. Light, and gauge don't really seem to care about what the other one is doing. There is zero correlation between the two.

I am confuzled. Gonna put the mech gauge on it here shortly, provided I can find it.

 

hmmm doesnt sound like mine... which is good news! definitely sounds like an electrical issue

sounds like a bad sending unit, has it ever been replaced?

 

Not yet. I HAVE a new one..... what I don't have, is the right size socket to put it in. Old one is 1 1/16th, new is... not..... I couldn't find the right size in my collection. (of course, I have moved several times, and a fair number of my tools 'disappeared' when I wasn't living at the same location as they were......) So..... verify pressures, if it IS just the sending unit, talk to my buddy that owns the shop, and see if I can sneak in there for 30 minutes one evening to change it out.

Of course, went out to work on it..... and the daughter drove it away. I haven't quite developed the knack for working on vehicles that aren't here yet....

 

hahaha that'd be a little tough to do

anyhow, advance auto sells oil pressure sending unit sockets, i unscrewed mine with a pair of vice grips but hey, after about 2 hrs i got it out!

then i saw that there was a special deep DEEP well socket for $5 when picking up the new sending unit and i REALLY-

 

As I have to work outside in the driveway, in the cold..... the 'two hour method' just ain't gonna cut it for me. Too old for that kind of behavior.

The engine should keep me nice and warm to hook up the gauge though. Hopefully.....