how do i check oil pressure with mech gauge (1 Viewer)

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hey guys i think my oil pressure gauge is going out, how do i check with a mech gauge the truck is 94 fzj gas american thanks
 

Trapper50cal

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It should read at the L line when at idle and steadily increase to the H or right below the H line when you hit the gas...is it doing something different?
 

Dave 2000

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The gauge sender unit is located down by the starter, they are known to be a bit flakey. Is your needle reading lower than normal? Is the engine due an oil and filter change? Throw some more info up here and the clever people will be along shortly. Oh and to answer your question..oops sorry, remove the sender unit found as mentioned earlier and simply screw your mechanical gauge into the hole.

Are you using a 'master' oil pressure gauge or a 'mickey mouse' one from the dollar store? The reason I ask is I know someone who rebuilt his engine based on the figures of a cheap unit...and he did not need to.

regards

Dave
 
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10 40 mobil one with mobil one fliter, just noticed that sometimes i have great pressure then it seem to drop off for a while then goes back up to normal area it has always ran at, just replaced oil pump seal crank seal and dizzy seal, i have never noticed any diff sounds from the engine when the gauge says its low, so i was thinking a bad gauge or sender, so i wanted to hook up an actual mech gauge so i could see what numbers im actually at
 
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by that i mean i could drive for 2 hours with great pressure according to factory gauge then it drops off and come back after a while, and ive had it drop low turned off the truck long enough to go pee and check the oil and it s fine and right back up on pressure when i start it back up thats why i believe my gauge or the sender is bad
 
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My 97 had poor pressure at idle and great under acceleration, according to the factory gauge. My mechanic hooked his gauge up to it and allowed me to drive around for a day with it connected. It read 28 lbs. at it's lowest and would reach 80 lbs. under hard acceleration. My mechanic is a Toyota truck guru and says the same as above, the gauge and sending units are finicky.
 

wngrog

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I have a current question.

1997 Collectors, 200,000 miles.

It belongs to my nephew so I don't drive it every day.

I did pick it up and drive it all the way home from Arkansas when we bought it.

I have an 80 with 165K and the oil pressure gauge runs at the top 2/3 all the time, it will drop to 1/2 at idle.

This truck, I just don't remember it being a low pressure truck. I think I would have noticed it.

I took it to a great shop today to have an ACC tune up kit put on it. I am not even sure what if anything they would have touched in this install that would have "bumped" the oil pressure gauge (maybe the fuel filter?)

https://forum.ih8mud.com/atlanta-custom-creations/448610-fzj80-tune-up-set.html

Anyway, I get in it and notice that it is sitting just above the bottom line at idle. It raises up nicely on acceleration to just under the 2/3 hash mark up to 3000 RPM. When I was coasting at 1800-2000 RPM it drifted down to around the 1/3 hash mark.

Seems to be going up and down with acceleration but it SEEMS like it is a full 1/3 on the gauge less than it was before the tune-up kit.
 

Squash

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Unscrew the sender unit from the block, install the mechanical unit, start the engine and voila!

Another option is to install a "T" fitting which will now give you the OEM and mechanical gauges.
When running the mechanical gauge into the cab I like to protect my lines from chafing.
 

wngrog

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My main question is that is there any way the sender could go goofy from someone changing plug wires and a fuel filter? I don't even know where it is. Is it close to the fuel filter?
 

Dave 2000

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My main question is that is there any way the sender could go goofy from someone changing plug wires and a fuel filter? I don't even know where it is. Is it close to the fuel filter?
I am unsure about your car but the diesel fuel filter is on the inner front wing (left viewed from rear). The sender is above the starter and to the right of the oil filter. It is a small round canister and has a couple of wires coming from it. Some (mine for example) also have an earth tag which when corroded can give rise to gauge problems.

I am not one for gauge duplication because I do not like 'clutter' so only use a master gauge temporarily whilst checking for problems however, I do intend to fit a low pressure warning light which my car does not have, I will be fitting a pressure switch that activates the light and buzzer if the pressure drops below a certain threshold perhaps 15 psi, i.e. just above the lowest pressure I expect to see at hot idle.

Despite being an avid gauge watcher I think you cannot beat a bright light and buzzer to stir you into action!!

regards

Dave
 

wngrog

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My 100 series runs about the same pressure as this 80 did yesterday...I just noticed it was below 1/2 on the gauge at 1800 rpm.

Still interested to know if the sending unit could have been disturbed.
 

Tapage

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I just recommend jump in to a trusted mech oil pressure gauge .. stock dash gauges are just there to give you a idea about your engine .. if you are concerned .. run a good oil pressure gauge.
 
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So, I'm guessing the movement of the gauge on pressure is just normal? I just bought my 80 series yesterday and was alittle concerned with the pressure changing so much. And I'll be introducing myself on the newbie section soon!
 

Dave 2000

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Holy optical illusion Batman!!

Look at the two oil pressure gauges of wngrog and 93 chewbacca, the 2nd and thrid marks are placed differently i.e. further up between the lowest and highest mark or is that just camera angle? My 94 gauge has markings more like the gauge of wngrog however, my oil pressure indication sits at just below the 3/4 mark at revs and the 1/4 mark at idle, I will be putting my master gauge on it next week because it is a little lower than usual lately, just remember these gauges are just soooo inaccurate!

regards

Dave
 

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