cheers again again - wondering if there is. way to test the 3 wire oil pressure sensor? its a 86 v6. car had no oil pressure before as cam missing lobes and bearings all toast... so now I got this thing all rebuilt, want to ensure sending unit is good before putting engine in car. id also like to use drill from above while distributor shaft still out and operate oil pump until I can register some oil pressure. anybody got and ideas? I could just temporarily thread a manual guage in, but I still would like to test the sensor/sending unit
The best way to prime the system and test the oil pressure sensor is to make a priming tool using an extra distributor with the teeth on the gear ground/cut off. Attach the drill and turn clockwise.
An idea I had about testing the pressure sending units requires using an air compressor. Devise a fitting to attach to the air line with the appropriate female thread on the other end. You would need a valve on the adapter piece. You would also need to braze a piece of braided ground wire or multi-strand wire to the adapter. Maybe 6-10 inches long.
Install the sensor into the adapter, set the compressor at 40 psi, turn on the valve of the adapter and attach or touch the ground wire to a suitable chassis ground. The decklid hinge is a good place. Plug up the sensor to the engine harness and turn on the ignition. Check that the gauge reads 40 psi.
If you're concerned about initial startup pressure, I'd just plug in the sensor and ground it to keep the gauge from pegging. Install a mechanical gauge until after you're finished running-in the engine so you know you have sufficient oil pressure.
Old distributors modified as Patrick described is the best way to prime because the base of the distributor seals an oil passage, allowing oil to reach the complete top of the engine. Weld a nut onto the top of the shaft and use an air wrench to drive it.
It can be a lot easier than what fierofool described as long as you have a multimeter.
If you absolutely want to check it before starting the engine, then remove it, and hold one lead from the meter against the sensor threads, and the other lead to the pin that the tan wire goes to. Set the meter to read ohms (in the <200 range). Then using a compressor set to 60 psi use the rubber tipped air nozzle that comes with even the cheapest air tool set and hold it tight against the oil port on the sensor and pull the trigger. You should get about 90 ohms on the meter. At 30 psi you should get about 45 ohms.
If you don't have a compressor of your own, then take the meter and sensor to any garage and they'll surely help you out for free.
Another alternative is to leave the sensor screwed into the engine and start up the engine with the connector disconnected from the sensor. Hook up the multimeter as described above. After a second or two of running, you should see the ohm reading on the meter quickly rise to about 90 ohms, and should gradually fall to about 45 ohms once the engine is warm and at normal idle. Goose the gas and the meter should read somewhere between 45 and 90 ohms.
oil sender is standard plumbing threads. Any air pressure will work. A normal bike pump will do for testing. Small tube to attach the pump then a couple fittings to match the sender.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
I guess I did over-engineer it a bit, but I was thinking of my own needs. I bought a truckload of Fiero stuff about 4 years ago and among the goodies was a bunch of used oil pressure sensors. I had planned to devise an apparatus whereby I could test them with a known pressure. I work on other person's cars from time to time, too. 40 PSI seemed like a good pressure when hooked to the car's pressure gauge so that it wouldn't peg the meter and possibly loosen the needle and straight up on the gauge is easy to see through the back window. But any pressure from any source and method will work as long as you know what that pressure is.
Replacing the sensor isn't really a problem. Minor to moderate mechanical skills are required. Easily done by removing the battery, holding the end of the oil pressure tube with an adjustable wrench and loosening the sender with a 9/16 wrench. Reverse the steps for installation. Be sure to hold the square end of the oil pressure sending tube to avoid breaking it when removing and installing the sending unit.
My hero... The oil pressure sender is the device that transmits data to the dash board indicator, correct? Mine has the ever present pegging tendancy, but it only slightly bothers me. bb
okay thanks guys, i think i'm going to just upgrade to 88 style and be done with it. if you don't mind theogre, would have a part number for the 88 sensor? my local autoparts stores show the 88 the same as the 85 to 87 sensor. although when they look up one of the connector numbers you provided in your ogre site it shows the updated connector, so they admittadly have a mix up their system, but still they can't tell me what sensor would be for an 88 and match the connector. if i had a number for the sensor they could cross that for me. thanks again guys.
If it's any help, I just converted my 86 with an AC Delco switch from Rock Auto. Part number was 01 D1808A --- Oil Pressure Sender/Switch The harness was an Airtex/Wells. Part number WMA 1F1053 --- Oil Pressure Switch Connector You could ask your parts store for a switch for an 88 Beretta 2.8 and get the correct one.
So as to keep this in the search subject title of oil pressure sensor, regarding my post above about converting to the 88 style sending unit, I've encountered another problem.
The battery has died twice since converting to the 88 style sending unit. Totally dead after a couple of days. Wouldn't even illuminate the trunk or interior lights. Day before yesterday, I charged the battery and upon removal of the charger, I tested at 13.01 Volts.
I disconnected the 88 oil pressure sender harness and without using the car, two days later, I still have 12.94 volts. I just tested the harness end and found that I have full power to one of the side terminals and no power at the other. I know the center terminal is a ground and won't have power. Should there be full time power on the harness? If there is, which terminal of the oil pressure sending unit should it be connected to? If not, what would be the cause of the hot wire?
The orn/blk wire (pin A on the old style sender) is always hot. (Edit to add: the '88 service manual shows that the orn/blk wire goes to pin C of the sender)
[This message has been edited by Bloozberry (edited 12-01-2013).]
My 88 harness is marked 12, the center is marked A and the other has no marking. I have the orange/black tracer attched to the 12 terminal. The center terminal is attached to the center terminal. Looking down at the sensor, it would be I * 12 with "I" being unmarked. There is no power on the "I" terminal. the * would be at the bottom near you.
So, in this picture from RockAuto.com the 12v is connected to the terminal on the right.
[This message has been edited by fierofool (edited 12-01-2013).]
I've left my oil pressure sensor disconnected for 10 days and the battery is still holding charge. I just did a continuity test on the 88 sender and without the engine running, I have continuity between the center and either of the other two terminals. I tested my original 86 sender and there is no continuity. Is this normal for the 88 sender? Can someone with an 88 do a quick check on their sending unit?
dgsmooth, I returned my sensor to Rock Auto and received another. I installed it and it's working properly with no issues. How is your conversion coming along?
