Dino oil pressure gauge and sending units

Yes, but on my Lancia Fulvia. It should be fitted with a Jaeger unit but was fitted with a Veglia one that gave constantly low readings. When I asked around it was a well know problem, I've got a Jaeger unit winging its way to me in the post as we speak so I'll know soon enough.

I was curious as to whether the unit in my Lancia was common to other italian cars of the 60's and 70's. Remember back then FIAT hadn't got its claws into Lancia and component sharing was more likely with Ferrari or Maserati.

Cheers
Simon

 

Surprised that the sending units are no longer available (especially since they go bad do often), but I believe it's the same as the sender on a 308.

 

just went through this exercise on the C4.

My Oil pressure started reading low – very concerning, at cold idle it would fluctuate between about 70psi and 20psi. I stuck on a VDO gauge to verify the pressure – actual pressure was fine – up close to 90-psi cold idle, the problem was in the gauge reading.

Using a 500 ohm variable resistor in place of the oil sender, and an ohmmeter, I charted what resistances were required for the meter to read various points. I don’t remember them very well, but 238 ohms was about 0 PSI and 109 ohms (I believe) was about 70 PSI. ( don’t remember what 100 and 140 PSI were accept that 140 PSI was getting close to 0 ohms.

I pulled the sender and using compressed air at specific pressures, I measured the resistance of the sender unit at various points. It was all over the map - consistently low/wrong.

I also made these same measurements on a new sender unit I had purchased from a parts supplier, and guess what – it was incorrect for the gauge and would have read significantly low across the board.

I believe the new unit was measuring something like 278 ohms at 0 PSI and 135 or so at 70 PSI. (My memory sucks at this point; so don’t count on the absoluteness of my numbers here, just that the replacement unit was wrong also)

Being the engineer I am, I took the old unit apart (actually my farther took it apart by bending the crimp back – lots of slow and careful tapping with drift punch) and found variable resistor with a wiper driven by a pressure piston. Over the years it had become gummed up. I cleaned up the sending unit with electronics cleaner and by bending the calibration tabs (yes – internal to the sender, there are little bendable taps on the tension spring where the factory calibrates the gauges) and using compressed air at different pressures, I reset the sender to match pressure/ohms with the gauge.

If you do this, it is important to use pliers to re-crimp the sender. Using a hammer to re-establish the crimp will knock the unit our of calibration – (I know from experience)

I also put a small bead of silicon around the base to seal it up.

With a calibrated gauge, I was surprised how high the oil pressure actually runs – but I did do a specification check – and the engine is running in the high end of the range – I guess that is good.

Best of luck,

Aaron

 

I dunno. We just replaced my sender with one from Superperformance and all is well on my car. A '72 GT.

No pressure reading problems, works great. It had been reading a little low before the swap.

DM

 

This is prevalent in many Veglia oil pressure indicators I've seen on Maseratis too. Many times you must adjust the scaling resistor as Aaron has done (sort of).

Electronics cleaner is amazing stuff. Cures/cleans electronic contact problems and several detail shops use it to clean the floor carpet in cars too!

 

I use Rod Drew in Costa Mesa. My 72 gts also reads low, tested with
outside gage, good pressure. The option I was given was to remove
both gage and sending unit, mail it to someone in Arizona who calibrates
both. Quoted $ 600.00 for the whole job.

 

Basically the gauge and the sender should be the same make. I had a Veglia unit connected to a Jaeger gauge. Found a guy on a UK Classic lancia chat room. He happened to have a box of fulvia bits and found the Jaeger unit I was looking for.

Cheers
Simon

 

Sounds right,
you have to match the scaling of the sensor with the gauge.