1999 Montero Sport Oil pressure gauge

[redcentinela]

Today I installed a new oil pressure sending unit sold by Beck Arnley, BA2010551, oil pressure switch. Same thing. No improvement at all. I made a test, when I grounded the cable that goes connected to the sending unit and turn the key switch to on like if I were to turn the engine on, the oil light at the dash board is completedly lit and the gauge needle goes all the way to the right. I don't know if this is ok but normally in a car without an oil gauge , like a 2001 mirage i have, the oil light goes on just before turning on the engine, because the oil switch is grounded. As soon as the oil pressure rises, it is not grounded anymore, thus, oil light goes off.

What I don't understand in this Monty , I connected the electrical cable back to the sending unit ( by the way it is only one cable) why when I turn the key just before turning the engine on, the oil light at the dash board remains off when it is supposed to goes on?

Still don't understand how this system works only with one cable. I measured the oil pressure with a mechanical gauge and readings are ok. I think I will replace that sending unit for a regular oil switch and forget about the gauge.

[redcentinela]

Another question I have:

I read somewhere that an extra oil pressure switch for the oil pressure lamp should be installed besides the oil pressure sender. Is this info correct?

I am asking because the there is only one sensor connected just on top of the oil filter, at the base.

[redcentinela]

Here is a picture of the sender for you to see that there is only one switch, the sender.

imageshack.us/photo/my-images/846/dsc07282j.jpg/

[slantsixness]

The factory Diagrams show this as an Either/Or connection. not both. If you have the Trio Cluster on top of the dash, that is your oil light? and the dash oil warning light is inoperative.
Sounds like you may be adding the gauge trio?

Look at joint connector 1 behind the right side of the dash. If your monty came with an oil light only, then Pin 11 is jumpered to pin 10.
If you had the gauge trio in the dash, Pin 11 is jumpered to pin 9.

if you want to run both the gauge and the light, install a fitting TEE, the sending unit and oil switch, and run a wire from the sending unit to pin 9 of connector 1.

Alternatively, reach up and remove the light bulb from the oil light and your gauge will work as expected. (the light bulb in the circuit makes the gauge read pegged).

[redcentinela]

Thanks for the info. I will verify that. The issue here is how come a factory equipped vehicule with the Trio Cluster make the oil light bulb inoperative? Both should work at the same time.

[redcentinela]

Should work both because I have a 1989 Isuzu Trooper also with a sender like this Monty with only one cable and both, oil light bulb and gause are working perfectly.

[redcentinela]

well, with too many Montero Sports still rolling around on the streets, apparently nobody can tell me if both , the oil light and the oil gauge work at the same time. It only takes one minute to find that out. If somebody could tell me, I'll appreciate it.

Procedure:
1- Turn the key to on without turning engine on, check the oil light if lit and gauge must be with the needle should not read any oil pressure.

2- Turn engine on and oil light must go off and oil pressure gauge must read oil pressure

That is all the info I need to know if both systems work at the same time or not like slantsixness says.

I am asking because for me it is not understandable how an older vehicule like a 1989 Isuzu Trooper with both systems work at the same time ALSO with only one cable connected to the oil pressure sender and a 10 years newer vehicule like a my 1999 Montero Sport don't.

[bdmontero]

Ill check here in a minute.

[bdmontero]

Mine went off and reads no oil pressure with engine not running.

[redcentinela]

thanks bd montero, for some reason when I turn the switch to on, oil light doesn't turn on and when turning on engine sometimes oil light turns on faintly when I suddenly accelerate engine and of course, oil gauge doesn't read any oil pressure.

I am sure there must be something in between that controls the sender and oil light to work like they are supposed to but apparently there is no one who knows this info, no capable electromechanic who can help me. Thanks for the guys who's seen this thread. Have a nice day.

[twood3006]

Maybe you need a new oil pump? How many miles do you have on your Montero? Not saying anything except it's a possibility.

What made you think it was the sending unit to begin with?

[bdmontero]

Maybe your oil pressure gauge is bad.

[redcentinela]

Well, according with service manual, gauge reads 50 ohms at the gauge rear terminals when tested with a multimeter. Oil pressure is correct, I measured it with a mechanical oil pressure tester. Miles are only 107,800.

[121gw]

redcentinela - interested to hear if you ever got this problem resolved. While I can't help with the light/gauge functionality questions you have, I did have some observations:

I have a '95 Montero SR 3.5L that started giving a "buried needle" reading on the oil pressure gauge a few months ago. The problem is definitely the sender, however I ordered the wrong one (the one for models without a gauge) and am now getting the opposite problem....no needle reading on the oil pressure gauge at all. Thanks to your post, I located the correct part for my truck...the Beck Arnley 201-0551 you mentioned above. It sounds to me like you may have received a bad one, since it is doing the same thing my bad one is. By the way, I'm reading 4.8 ohms across it, far from the 50 you mentioned.

Thanks again for the indirect help!

[redcentinela]

No problem my friend. I am still having the same problem.