Thread: Where to hook up oil pressure & volt gauge

This is what i found. All credit goes to webracin

"There is a plate that holds the oil filter. On that plate you will find the oil sending unit for the stock system. You can remove the stock sending unit and replace with a sending unit for your guage, OR, get a gasket for the plate, remove the plate and drill and tap a hole next to the original sending unit. You will need a 45 deg elbow so that the sender does not hit the CV axle, but I have been runing mine for over 5 years with no problems."
webracin

^I just removed the stock one. Its really junk anywayz, just goes to a dummy light in the dash and only goes off when you get below 5psi <which is pointless. Now i can accually monitor the pressure.

Im moving this to the right section this time but I would encourage you to read this:
http://www.grandprixforums.net/f14/a...read-6828.html

Post #7. I came very close to deleting this. I cant make the information more available, more plain or anything. Please pay attention to where you are posting and make sure it is in the correct section.

Technically the PCM does monitor actual pressure through the one you removed. Just because you don't have access to that value doesn't mean it doesn't work. My 3.8L has the same sender and my car came stock with a working oil pressure gauge.

The Bonnevilles and the Impalas and I assume others come with a three wire sending unit, the GP only got a two wire sender which as mentioned just basically trips the low oil pressure light on the dash. Why they cheaped out the GP Im not sure.

It's seriously different? I can't believe they changed it from a oil pressure sender to a oil pressure switch just for the GP.

They did, Ive had to replace the sender on a Bonnevile before and its a different sender from the GP. I was kinda shocked myself, but thats how it was.

I like GM because most of the time I understand why things are the way they are.

This is an exception.

Yeah, it made no sense to me at all either. The guy brought the car to me and said that his oil pressure gauge was not reading right (my first thought was that he didnt know what gauge he was looking at since the GP didnt have a pressure gauge) and then proceeded to hand me the oil pressure sending unit. I looked at it and told him he had gotten the wrong one. He swore up and down that it was the right one.

So I crawl up under the car, pull the plug off the sender and sure enough, it was the right one. I checked the dash and sure enough, there is a bona fide oil pressure gauge in the Bonneville. After that point I was mad. Why didnt the GP have one?

Though, I have thought if it would be possible to run the Bonneville sender and have the dummy light on the dash work as it should on the GP and use the extra wire to run to an after market gauge so that you get the best of both worlds.

I mean, you arent always looking at the gauge pillar and at least there is some warning on the dash that is functional that would catch your eye.

Originally Posted by SyntheticShield

Though, I have thought if it would be possible to run the Bonneville sender and have the dummy light on the dash work as it should on the GP and use the extra wire to run to an after market gauge so that you get the best of both worlds.

You'd need a gauge calibrated to the PSI and impedance range of the factory sender. I don't know those ratings, unfortunately.

True, but it could be worth the experimenting at least.

Trans temp isn't much good unless you can bury the sender deep inside the transmission where the factory sender is. I just monitor it through the PCM.

I personally would like to have both transmission and oil temperature gauges without having to use a scan tool to monitor stuff like the trans temp. However, if I were told I could only do one my first priority would then shift to trans temp because it frequently can get into ranges that cause severe breakdown of the fluid. You want that temp down in the 170* range. Anything over 200* and youre subjecting your fluid to a temperature that will start to break down the fluid and is kinda rough on the trans.

Now if you run synthetic trans fluid you have a little more cushion but even so its just good all around practice to keep the trans fluid around 170* or so.

People change the oil frequently enough that temperature stresses there are not as significant typically though they can be. But you dont want the oil temp up too high because it will start to evaporate off the smaller hydrocarbon chains in the oil and cause evaporation boil off. Likewise, you dont want the oil too cool either because then it cannot evaporate out any fuel or moisture contamination which when in excessive amounts can thin the oil out to dangerous levels or cause sludge and varnish build up.