I’m looking for technical help or recommendations on: Causes of hesitating acceleration and revs
Hi, I’ve been working on my project mx5 for a couple months now and it has a really annoying hesitation issue which I can’t seem to work out. It has an almost 1 second delay between the throttle body opening and the engine revving.
I have replaced the plugs and leads, as well as adding a cobalt cold air intake. Along with this I recently cleaned the upper inlet manifold and EGR valve as best as I could. There is no vacuum leak that I know of as I checked this not too long ago.
Just wondering where I should be focusing my attention to get the issue solved as it has been bugging me for a while. Thanks in advance for any help provided
I haven’t changed it, is that a common cause of some hesitation? I guess it may be restricting fuel flow. There’s also a strong smell around the car whilst it’s running, could the fuel filter cause this as well?
I’m certainly no expert but the fuel filter is a service item often neglected. Ask me how I know
My car is also a 1.8 NB from 2000. It’s covered 148k and I have no record of the fuel filter ever having been changed.
Needless to say it’s on the list of jobs for this coming year.
I plan on using a genuine Mazda item even though they’re not the cheapest. It should be changed every 5years or 56k miles.
It could be worth considering?
Even if it doesn’t fully cure the hesitation I’m sure it’s a job that needs doing as mine too has no history of it being replaced.
I’ve ordered a new filter and clips and am looking forward to getting covered in fuel doing the job
Thanks for the help, will let you know how I get on and if the problem still occurs
I am very interested to hear how you get on.
I’ve watched a number of videos on YouTube to see how to go about it.
One piece of advice that crops up regularly is getting the correct tool to remove the fuel lines. The plastic clips that secure the pipes in place require this special tool which makes it easy apparently.
I’m a bit fearful of what I’ll find as the pipes can corrode quite badly.
Also, it might be prudent to have something to plug the pipes or catch the petrol.
One video suggested pulling the fuel pump fuse under the bonnet to relieve some of the pressure.
Hth.
I had this on a mk2.5 ,
Found to be rocker cover gasket leaking oil , oil then tracking down the wiring on to crank position sensor.
Changed gasket, cleaned wiring and sensor… been great since
Thanks for both the replies. I’ll replace the fuel filter and whilst under the car I’ll have a look for any oil leaks trickling down the engine.
Would cleaning the sensor be a quick was to tell if that is the root cause?
Monty…
Have you done a diagnostic check?
This kind of problem could be fuel starvation where the demand for fuel is stalled temporarily but more like an electronic issue where there would likely be an electonic diagnostic error signature?
Certainly worth a starting punt anyway.
I have done the good old LED diagnostic check a couple times as it’s pre OBD2 and nothing has come up. However, this lack of error codes may just be where I keep disconnecting the battery to work on the car.
I did run the car for a while without disconnecting the battery and still no errors came up, so I’m assuming all the sensors and electrical components are operating normally
I would say a momentary stagger is fairly common with worn spark plugs, HT leads, etc, but your starting/driving experience does seem to be a step past that.
The MX5 fuel pump is a robust beast but can suffer issues.
Having replaced the parts the ecu does not monitor, plugs and leads, etc, fueling would seem the likely issue. Fuel filter change is cheap and something you can do yourself; another thing ticked off the list.
Thanks for the help, hopefully it is solved by either replacing the fuel filter or messing around with other parts of the fuel system.
Would it be possible for the fuel injectors to be the issue? There’s no fuel leaks from the fuel rail/injectors so they seem to be sealed fine.
Hi my mk3 2.0l was hesitating on acceleration and I added red x injector cleaner to the petrol tank,just two treatments cured mine ,hope this is helpful,let me know if it works.
