I recently bought a 1992 1.6 Roadster and have noticed that when accelerating hard (above 4500rpm) the oil pressure gauge fluctuates wildly. It “feels” as if it might be the engine vibration causing it OR that the engine is about to blow up when revving hard !Otherwise the gauge works fine - oil pressure increasing under engine load and decreasing when cruising.
I’ve heard that the mx5 oil pressure gauge is a mickey mouse gauge. Is this what is causing mine to fluctuate wildly? Could it just be engine vibration or a loose connection? Or is my engine detonating and about to pop? (I can’t hear any engine knock)
I’m thinking of measuring the resistance across the oil pressure sender and checking for loose connections… but before I get stuck in was hoping for some advice.
I’m no expert on these engines, but the first thing I would do is to make sure that the connection on the oil pressure sender unit is clean and a tight fit. When was the last time the oil was changed and was it for a good quality oil? The reason I ask is I had a similar problem with my Sunbeam Lotus that under hard accelaration the oil pressure guage reading would start to drop or fluctuate, so I checked connections replaced oil with good quality one, in my case for that car is Valvoline Racing 20w/50, job done.
I guess someone here with more experience with Mazda/Eunos engine will put you right.
The oil pressure gauge on a 1992 model should be one of the proper ones that actually shows the oil pressure and not just on or off. It certainly is on both my 1992 cars.
Since it’s not losing pressure, just vibrating/fluctuating wildy do you think it could just be a loose connection? or maybe detonation at high revs? I’m going to check the timing this weekend and will let you know if anything crazy is going on. ANy other ideas?