Intermittent misfire, and reading error codes 2003 NB 1.8I

[petefoth]

1. My model of MX-5 is: 2003 v2.5 1.8i
2. I’m based near: Whaley Bridge, HIgh Peak
3. I’m looking for technical help or recommendations on: ignition, misfires, reading error codes

'm a new member of MX5OC, and I have owned a 2003 v2.5 1.8i for about 8 years, which now has 102k miles on the clock. For a few weeks it has been suffering an intemittent misfire, usually in 2nd or 3rd gear, between 2,500 and 3000 RPM. Until today, the engine warning light has never come on. I have replaced plugs and coil packs and I think the engine is running a bit smoother, but sadly the misfire has not gone away.

Today it happened again, this time in 4th gear around 4k RPM, just after overtaking. This time however, the engine warning light did come io, and has stayed on after a restart. So I think there should now be some interesting infirmation to be had from reading the ECU error code. Unfortunately, my local garage is unable to read the error codes since they “don’t have the correct adapter”.

Is there an easily obtainable bit of kit that would allow me, or my local garage, to read the error codes? (I know more abou, and have more experience with computers than I do engines, so this is something I think I might be reasonably happy to try myself).

Alternatively, is there a quick way to get at the error codes without buying any kit myself.

Thanks in advance for any ideas, suggestions or advice.

Pete

Edit:
More searching in the forums led me to these two threads, which identify the Air Flow Meter and/or the Throttle Position Sensor as possible causes. I will investigate both of those but, now I have a real live error code, I would still like to read it if I can

Mark 2.5 spark plug connections

Your description of the problem indicates that the car is running on all 4 cylinders without misfire. Have you tried cleaning the contacts on the Air Flow Meter or replacing it if this does not work? The AFM is the black plastic tubey thing just after the air filter box, fitted in the rubber air pipe and marked FS1E. If this is malfunctioning you will have running problems. Very easy to replace and test - couple of pipe unions and two 10mm bolts from memory. 

NB 1.8 (2.5) Engine fault when hot, crank sensor fixed it

Hopefully the new TPS will sort it Paul - certainly the error code is very specific. Have to say I would usually recommend replacement of the entire throttle body with all sensors for a known working used item. These are the same for all MK2/MK2.5 cars and available very cheap as do not generally give issue.  You have the error code and what appears to be proof that the unit is faulty so much easier just to replace the TPS - hope it works, let us know.     

[rhino666]

Pete

Your garage are considering the diagnostic socket under the bonnet when there is a standard OBDII socket under the dash where the drivers right knee tends to be.
Any OBDII reader will get the error codes off your MK2.5.

[petefoth]

Thanks. I’ve decided that I should make more effort to fix things for myself, rather than relying on garages for everything, including the trivia jobs. (This is one of the reasons I joined MX5OC).

It seems that an OBDII reader would be a useful thing to own. A quick search of Ebay turns up about 8,000, most of which look v. cheap and nasty. Can you (or anyone else reading this) recommend a model or a supplier?

[rhino666]

Yes I can. Buy yourself an MS309. I will add a link in the minute. here is the best I can see from a UK supplier.

[petefoth]

Thanks again. Ordered and paid for

[999to5]

Any recommendations for software/app to support it??

[petefoth]

From the pictures and the description in the ad, it seems to be a stand-alone device that doesn’t need (or indeed support) connecting to any other device. I’m expecting to drive it using the Scroll and ‘Enter’ buttons, and to make notes (pen and paper, phone camera) of the information / error codes it shows me.

[999to5]

Fair enough.
I have a Bluetooth type scanner that I used on my motorcycle and connected to an app on my phone.
I was hoping for a recommendation for an equivalent app for my Miyako.

[petefoth]

The reader has arrived. Car is showing 1 error code

P1345 $0010 1/1 Other
Manufacturer control

which I guess is a Mazda-specific code. I will go a-googling, but if anyone knows off the top of their head what that code indicates…

Pictures of Error code and Freezeframe data attached

[Roadster_Robbie]

Cam Position Sensor circuit malfunction. Does it clear?

[rhino666]

I am surprised that there isn’t a generic description for P1345.
quite often a non start on this code or absence of it where non start and engine not cycled enough to produce a code. As Robbie says, reset code and see if it comes back.
Quite often relates to crank sensor from my experience which is confusing where Mazda specific description is CAM sensor.

[petefoth]

Thanks both!

The warning light went out the second time I restarted the car after it first appeared.

Should I clear the error using the reader, then wait and see if the code reappears?

Can the code occur without the warning light coming on?

Is replacing the crank/CAM sensor a relatively straightforward job?

[petefoth]

@Roadster_Robbie

Cam Position Sensor circuit malfunction. Does it clear?

It cleared, and has stayed clear for a few days now. MS309 showing no codes.

Not had any misfires now for several days, and only the one - which caused the Check Engine light to come on - since changing the coil packs.

The MS309 now lives in the glove box so it’s at hand if another is fire does occur. Thanks for all your help, and I hope I won’t be back