good afternoon
can anyone help me…
i have a 1.8 mx5 2006 that is new to me
i noticed the other day (because my wife pointed it out) that when driving the needle on my oil pressure gauge fluctuates. Basically when I accelerate the needle goes up and when I take my foot of the accelerator the needle drops back down…on my other cars the needle stays put in same place
is this fluctuation normal on a mk3 mx5?.
any advice would be appreciated
regards
Sir Clive
It’s normal, no worries.
Yep - as MickAP says, they all do that!
As the engine spins faster, the oil pump spins faster, producing an increase in oil pressure. Old school (eg think MGB or Midget) the gauge was fed a direct reading of oil pressure via a thin capillary tube from a sender on the block. Then engines used an electric pressure sender which gave an electrical output to the gauge - again varying with oil pressure. My '94 Eunos 1.8 has this type of gauge. Later Mk1s (including my 1996) had what is basically a switch - on or off. Any oil pressure means the gauge shows full oil pressure - pretty useless really apart from in the event of catastrophic oil loss, when the gauge will confirm what your self-destructing engine has already told you. Mk2 oil pressure gauges likewise.
I believe that from the Mk3 onwards the ‘pressure’ is derived from an engine speed function of the ECU - so it fluctuates in the correct way, with the speed of the engine, but isn’t actually a true oil pressure reading.
Bottom line is - don’t worry about it. DO worry about always keeping the oil to the Max mark on the dipstick (especially your Mk3) - and observe service interval oil changes.
Thank you so much guys…puts the mind at rest
is it also normal that under hard acceleration (going up hill) that one notices smoke coming from the back of the car…never noticed it before or since
NO, sounds as though your engine is on it’s way out, piston rings is my guess. due to lack of oil or not changing the oil.
Too little, too late.
Bumping this thread as the last posting by the original poster seems to have been missed and deserves more investigation.
For me his engine is on it’s way to the scrap yard.
Only worth worrying about if it’s blue smoke, hard acceleration up a hill will produce more exhaust gasses.
Could just be water from the exhaust which would be white smoke. Suggest you check the oil level when the car is cold and see if it goes through any oil. Some owners modify their dipsticks to make them easier to read.
I think Clives car was a forum members car and was looked after meticulously so it wouldnt be due to lack of servicing. I think also it is decatted with new ss headers, exhaust and remapped so that could possibly be something to look at.
Hi Raymond
May sound a silly question but what do they do to modify the dipstick as i find it hard to read accurately?
Thanks Richard, much appreciated.