Oil pressure sending unit

[Joshua Nichols]

So I went to the auto part store to get a oil pressure sending unit.. Well that don't work.. They run backwards, plus the guys at the part house can't find anything less they can look it up on a computer.. SHAME.. Anyhow came to the conclusion that I am going to have to buy a marine OMC one.. $50 bucks..Yikes.. I guess you can't buy anything for the engine at a part store short of plug wires, spark plugs and oil..

I figured the oil pressure unit had seen better days, cause it looks pretty rough and I am losing pressure after we been running on the water for a while.. We have a few no wake zones and the pressure seems pretty low when we slow down for those areas.. I had a ol Jeep that use to do the same thing and it was the sending unit.. I don't think the oil pump is going out or at least hope not... I get no knock clatter or anything off the sort..

Should I try and install a mechanical gauge teed off the regular gauge? Or bite the bullet and buy the OEM sending unit? How low is too low? My gauge runs around >40psi at 3500rpm

 

[dsiekman]

Re: Oil pressure sending unit

If your engine is up to temp the pressure will drop pretty good when you come down to idle. For example, I have Volvo 5.0s. At full temp they run 40-60 psi at cruise and will drop to about 10-15 psi at idle. From what I understand, as long as I'm at 20 psi at about 800 rpms I'm fine.

 

[LAC_STS]

Re: Oil pressure sending unit

The hardest part of working on a boat engine for me was dealing with the IDIOTS at the parts stores.

My friend who works on engines too told me ten times to only go to NAPA.


I finally listened to him and started going to NAPA and I will not go anywhere else now.

All the other parts stores are worthless. The employees there do not know anything if you don't have a year make and model of a car and its in the computer.

I got kicked out of Pep Boys which was my last straw.

I asked the guy there if they sold remote start switches. He told me isle whatever. I went to the isle and all there was was car alarm stuff. I went back to the counter and said I was looking for a switch that lets you crank an engine without using the key IGN. I said it pretty much two wires with a switch on one side and clips on the other.

You know what he said to me??? He said all we have is in that isle and these right here. He pointed at some car alarm remotes that were on a little rack on the counter. I tried once more and he gave me the bs about what year make and model. I couldnt hold it in any longer and I said some things I shouldnt have.

I swear they are either really stupid or just dont care to try. Probably because theyre making $8an hr. i dunno. Now I go to NAPA. I just tell th guy at NAPA I need this or that for a chevy 350 motor and he brings it out.

Sorry for the rant. try NAPA.

 

[Eric 3.7LX Alpha 1]

Re: Oil pressure sending unit

I think the tee and mechanical gauge with the sender is a good idea.

 

[jmanf150]

Re: Oil pressure sending unit

Nice!

 

[Joshua Nichols]

Re: Oil pressure sending unit

It is quite depressing.. Use to sell parts and equipment.. I use to pride myself on to know as much as possible about the stuff we sold and the parts for them..Yet I didn't make 8 bucks a hour either..

The first place I went they pulled out a temperature sender.. I went somewhere else after that.. She was having such a hard time finding what I needed.. I thought the oil pressure sending unit would be pretty generic from automotive to marine but I guess it isn't.. Had to return the automotive one today..

 

[Joshua Nichols]

Re: Oil pressure sending unit

I think the tee and mechanical gauge with the sender is a good idea.

The only problem is I am wondering if they have one with enough line to get it to the dash on my tub.

 

[HT32BSX115]

Re: Oil pressure sending unit

Should I try and install a mechanical gauge teed off the regular gauge? Or bite the bullet and buy the OEM sending unit? How low is too low? My gauge runs around >40psi at 3500rpm

Howdy,


I bought my "new" oil press sender from Napa. It wasn't $50. I don't remember how much it was but it wasn't all that much.....

 

[Joshua Nichols]

Re: Oil pressure sending unit

HT32BSX115

Well I got one from Oriley.. It was 20 bucks or so.. But it worked backwards.. They couldn't tell me if it was 60 or 80 psi gauge... It had a spade terminal instead of a post like mine..
I am going to try NAPA tomorrow.. Just to see if they have one that will work.. I wouldn't think it would have to be a OEM marine type... The gauge in the dash works like any other one I ever ran into.. I grounded it and it pegs out like all the others I ever tested..

Anyhow I will follow though on this thread and let yall know I went on NAPA's website.. Lookie there.. Looks just like mine (minus the rust and paint)... Worth a shot $33. I use to use NAPA and I know better, than to go to the retards..

 

[HT32BSX115]

Re: Oil pressure sending unit

HT32BSX115

Well I got one from Oriley.. It was 20 bucks or so.. But it worked backwards.. They couldn't tell me if it was 60 or 80 psi gauge... It had a spade terminal instead of a post like mine..
I am going to try NAPA tomorrow.. Just to see if they have one that will work.. I wouldn't think it would have to be a OEM marine type... The gauge in the dash works like any other one I ever ran into.. I grounded it and it pegs out like all the others I ever tested..

Anyhow I will follow though on this thread and let yall know I went on NAPA's website.. Lookie there.. Looks just like mine (minus the rust and paint)... Worth a shot $33. I use to use NAPA and I know better, than to go to the retards..

I still have mine in the tool box. I can measure it with my Fluke 189 if you want to know what the zero pressure resistance is. Those senders are pretty much standardized.....

Ok,

I went outside and got both of them. One came off my previous OMC King Cobra 460 and one was on my Merc 454. (I thought one of them was defective)

Neither is.... One measures 240 Ohms at zero pressure and the other one measures about 260 Ohms (they're both close enough.....they're not LAB instruments!!)

When you the increase pressure on them, the resistance drops.

The oil pressure gage is a simple milliammeter.

It just measures current through it. With the resistance of the sender at a high level, the meter reads low.

When the pressure rises, the sender resistance drops and the meter goes up-scale.


Same with the temp sender.

 

[Joshua Nichols]

Re: Oil pressure sending unit

Well since they didn't have a clue what they was giving me IDK.. I put the one on they gave me.. It would read about 60psi.. Raise the throttle some it would go down.. It has always gone up, even with the ragged one on.. So the conclusion I came up with is the new one from O Riley has a backwards resistance.(for whatever chevy junk it fits on). IDK I didn't build the thing and I have already taken it back for my refund so no resistance check can be done...

I am sure I will get the correct one from NAPA.. Will let you know how it goes..

 

[Joshua Nichols]

Re: Oil pressure sending unit

Well the trip to the local NAPA wasn't as smooth as should be.. They tried to give me the wrong thing too.. But it just so happens I looked it up before I headed over to the part house and had "their" part #... They didn't stock the part but will be there in the morning.. At least they wasn't stupid kids and spoke good English...Can't blame em for not knowing much about marine type stuff...

 

[HT32BSX115]

Re: Oil pressure sending unit

Yeah......they're not perfect as it were......


You CAN go to West marine and get one too....


http://www.westmarine.com/webapp/wc...toreNum=10106&subdeptNum=10474&classNum=10475

 

[Joshua Nichols]

Re: Oil pressure sending unit

I am suppose to have a west marine close to my home but I couldn't kind it last Saturday.. I used their map and it said there is one there.. So may go on a adventure if it rains.They may have other goodies I can't live without. Otherwise it's laketime.

 

[Joshua Nichols]

Re: Oil pressure sending unit

Installed sending unit today.. Yep made the difference.. Turns out a bunch of folks at NAPA didn't get their stuff shipped in.. They said sorry and shouldn't happen next time

 

[rodbolt]

Re: Oil pressure sending unit

and ALWAYS remember, the marinizer may or may not have sent the gauge pakage with the hull. thats up to the hull manufacturer or the installer.
VDO and a few other brands everything works backwards than the teleflex,faria and a few others.
so you dont buy senders for the engine but rather the guage.

 

[Joshua Nichols]

Re: Oil pressure sending unit

Yeah I figured that one out.. Its a new one for me but i understand the difference now..