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Hey there fellas just got a question about engine timing.

I've got a 94 na8 and when i start up cold i have quite a rough idle - it hunts a little bit, maybe 50-100revs. Then when i start driving, it seems very down on power until it warms up a bit, it gets a bit better on power (or maybe thats just me getting used to it). But it does seem down on power full stop. It also seems to use a lot of fuel and run a bit on the rich side hence my suspicions of timing.

When its cold i also notice it has more oil pressure then when its warmed up. Cold it will idle at about 4, warm at about 3.3. Is this normal?

Sorry about all the questions i haven't had my mx5 very long and i'm just hoping nothing is wrong with my baby, i love it so much its not funny!!!!!!!!!

Cheers,

Jono.

Unplug the o2 sensor, go for a drive, come back to thank me.

Dann

Unplug it permenantly?

Also where do i unplug it from

Unplug it to find out if its buggered, follow the wire from the sensor, it will lead to the back of th ehead around the coilpacks, unplug it and tie it to something so it doesnt flap around on the road, go test drive.

Dann

NitroDann wrote:Unplug it to find out if its buggered, follow the wire from the sensor, it will lead to the back of th ehead around the coilpacks, unplug it and tie it to something so it doesnt flap around on the road, go test drive.

Dann

Is that the sensor at the bottom of the extractors?

Yep.

Dann

It's an NA8. So 4 wires on the O2 sensor, not one, and the plug is located just behind the cam cover on the left side and in front of the cam angle sensor.

I suspect that the O2 is only one of the problems. Could be other issues there with timing, temp sensor, throttle position sensor adjustment or even (an NA8 specialty) blockage in exhaust system. Nothing really expensive or insurmountable - just needing more detective work.

I just un plugged the 02 sensor and took it for a run no real difference - maybe a bit of placebo effect. Confirmed by plugging it back in and no difference. And i also made a mistake, cold my car idles at 4 and warm it idles at 2 (oil pressure), anything to be concerned about?

Thanks for the help so far..

Jono.

The oil is thicker when cold so that normal.

Not 02...

Unplug tps and go again.


Do you have an oiled air filter like a k&n?

Dann

Stock intake full stop. Standard paper air filter albeit a bit dirty, nothing serious thou. Which plug is the tps sensor

Throttle position sensor, on the throttle.

NitroDann wrote:Not 02...

Hang on. If there's no difference between a sensor being plugged in and not plugged in then doesn't that say the sensor is doing absolutely nothing?

manga_blue wrote:

NitroDann wrote:Not 02...

Hang on. If there's no difference between a sensor being plugged in and not plugged in then doesn't that say the sensor is doing absolutely nothing?

hahaha i was wondering the same thing! I guess i cant really answer that..

I just tried the tps sensor and i dont think that made any difference either.

take it to a mechanic.

Baseline service it (yourself), so that you know all settings are correct & consumables are new & working.