Hi all! Lately, I have got a «problem» that is not logic.. When I turn on the ignition, the red oil can indicator shows up in the multi display. I can never remember to have seen that before. When the engine starts, the pressure needle goes up immediately like normal. On the way down here I noticed that while cruising at 3000 rpms. the pressure was quite high. I haven’t really paid attention to how high the pressure gauge should go, only that it should not drop to zero on a warm engine on idle. And it never have been so low that it has not enough pressure even when it is quite warm in city traffic. The red light goes out after about eight seconds now. Before, it was only a few seconds. This happened after a bit hard Autobahn driving. The pressure gauge needle don’t Seem to go as high anymore and is more «normal» these days. This don’t make much sense. When looking at the parts diagram, the sensor have two wire connections. Anybody know if the two connections/pins are a variable resistance depending on the pressure (being the same circuit) or If it has one «low pressure switch» output to the MULTI display and the other output being a variable resistance going to the pressure gauge? I will try replacing the sensor, but it is pretty stiff at GBP 110 or now 75 on sale from Eurospares. Those sensors use to cost 20 euro on a normal car. Any know If it has a cross referance and can be bought locally from another car? I don’t believe I have an actual low pressure situation as the needle goes straight up and seem to work like it should. Image Unavailable, Please Login
The low pressure switch goes to the Digitek processor for the multi-display only. The variable resistance goes to the analog gauge. I haven't been able to confirm if the variable resistance also goes to the Digitek processor (as shown in the 550 wiring diagrams). I don't know if you've replaced a sender before, but they can be pretty hard to unscrew. Large spanner required and possibly a heat gun. Some recommend driving the car to warm it up, but then everything in the engine bay is hot (and a burn hazard). Knowing Ferraris, space to swing a spanner is limited. Note that the terminals are pretty fragile. Do not overtorque the nuts. Use the spring washers (if any) to hold the nuts in place. How's the oil level?
https://www.ferrarichat.com/forum/threads/456-oil-pressure-sensor.558924/ It might be easier just to buy OEM.
Thanks! The oil Castro GTX and it is brand new and the level is right too. But as the dry sump pressure pump is working, I can’t see why how low level should make these problems. Then it had to be empty, but the oil pressure come up instantly when starting. The car never ever make oil smoke and it does not leak either. It runs like a new engine!!! I guess a new one is the only way.
Eric, be sure the electrical terminals on the oil pressure sensor are clean. Dirt/oil can accumulate on them and can form a secondary electrical path to earth and this will cause the oil pressure gauge to give a false reading. It's a known issue with these sensors. As Ian pointed out in that thread link, there are electrically equivalent sensors available from VDO, but none that have the same M18 thread as the sensor they make for Ferrari.
Thanks for great replies. I ran the car for a few days without the engine undertray now a month ago before I changed the oil and replaced the fan shroud with a new 575 shroud. It might have got some dirt and bad contact because of that.
Erik, Here's the link to the oil pressure sender boot at Ricambi America: 135940-B OIL PRESSURE SENDER COVER Barry
I had the same problem. Cleaned the sensor connections and it went away...for 2 yrs...problem has resurfaced recently...I guess a new sending unit is in order
I recently had the issue with the oil pressure pegging at full scale on the meter. It's reported elsewhere - it's caused by added resistance in the contacts. I do have a slight leak from the front cover (also a noted issue), which caused the contacts to get dirty. I tried to clean the contacts to the sensor, but was not satisfied. Cleaning is not a permanent solution. So I said screw it and cut off the tab connectors on the wires and put on terminals. I unscrewed the nuts on the sensor to remove the tabs. As I was screwing on the nuts over the terminals, one of the bolts broke internally. (The bolts are knurled - not designed to be unscrewed.) So I had a 50-50 chance that the one that was securely attached was for pressure and not the warning (can't see it in the tight space). I got lucky - the pressure gauge was working. First thing I noticed was that the oil pressure indicator needle moved off zero when I turned on the ignition - it never did that before. And the needle no longer pegs. As for removing and installing the sensor, when I worked on a sensor project a couple of years ago, I was not able to get a wrench on the large nut on the sensor without lowering the sway bar. But the sway bar comes down with 4 bolts, so not a big job. I bought an oil pressure sensor with 1/8 NPT threads from Summit Racing (it's designed for terminals, not tabs), and bought M18-1.5 to 3/4 NPT and 3/4 NPT to 1/8 NPT adapters from McMaster-Carr. Next oil change I'll put in this new setup. I also bought some old sway bar supports on eBay and had them cut down to about 1/4" thickness to use as spacers. I got longer bolts for the sway bar supports and installed the spacers. This gives some peace of mind that should the motor mounts fail and the engine drops, the oil pressure sensor won't break off on the sway bar, dumping all the oil and trashing the engine. (I got this trick from this Forum, can't remember who.)
