HELP.........

[rodgerz88]

Hi guys, I'm very hopeful that someone here may be able to help me out as I've been dealing with this issue now for over 5 months! Starting to get a tad annoying.

First bought my car around a year ago, full service history, drove like a dream. One day I came to drive the car and this irritating issue appeared.

Now the symptoms I'm having is the car feels gutless until it reaches around 4000 rpm. It still goes, but it feels like there is no torque. In the lower rpm the car splutters and hesitates quite badly. There is also a trickling type of noise when under load.

I've had a mechanic look at the car and he says it fine, but I know there's something because as the driver I can tell.

The things I've done so far;

Changed o2 sensor
Changed coil pack, lead and plugs
Changed the cat converter
Checked engine timing
Checked engine compression


I'm starting to run out of ideas now. The next two things I'm going to try is the fuel injectors and the possibility of a vacuum leak somewhere.

Oh and I've also just unplugged the o2 sensor today and for some reason the car feels better. Not completely but a lot better than it did. There is still a trickling noise and a slight hesitation but a lot of the power is back. Confused now!!

Does anybody have any ideas? Any advice would be greatly appreciated.

[Steffan]

Try the EGR valve the symptoms could well be caused by EGR failure/sticking. Otherwise could be manifold or fuel assembly or air leakage or ECU/injection problems. You really need an MX5 testing electronic assessment of exactly what is happening. I suggest a good specialist MX5 garage NOT main dealer! The days of guessing modern injection fueled ECU based faults has gone. You need an electronic reader and someone able to use it.

[Steffan]

Try the EGR valve the symptoms could well be caused by EGR failure/sticking. Otherwise could be manifold or fuel assembly or air leakage or ECU/injection problems. You really need an MX5 testing electronic assessment of exactly what is happening. I suggest a good specialist MX5 garage NOT main dealer! The days of guessing modern injection fueled ECU based faults has gone. You need an electronic reader and someone able to use it.

[MX-5 Lazza]

Below 4k the ecu runs from the various sensors. Above 4k it runs from built in maps. As yours appears to be ok above 4k then I'd assume that it's a sensor problem relating to fuelljng. Unplugging the O2 sensor I would guess will make the ecu again run from sensors.
I would check O2 and engine temp sensor.

[rodgerz88]

Thanks for your help guys. So if it was a sensor, would it not throw up a code on the dash? The light definatley works as it came on when I disconnected the o2 sensor.

I changed the o2 sensor at the start of this episode so I'll purchase a temp sensor and see how it goes. It doesn't emulate the clutch judder problem does it on the mk2.5's?

[MX-5 Lazza]

Sorry mate, I've been away on holiday for the last 2 weeks

Have you made any progress with this?

Some sensors will result in a CEL (engine warning light) but some wont. An engine temps sensor for example will often fail by giving a constant signal rather than changing with the engine temp. The ecu has no way to know that the reading is false.