Mazda Repair: MX5 1.6 MK1, air flow meter, throttle position sensor

Question
Hello,

I have a Mazda MX5 1.6 MK1 (eunos roadster) which I brought about 5 years ago. I haven’t driven it much, its mainly been in my garage. I finally got it back on the road (insurance,tax,MOT) but it developed a problem... It starts every time without a fail but cuts out after about 15 seconds. I called the AA after checking the common faults (spark plugs,air filter and fluids). He could not pin point the fault but told me he thinks its a problem with the AIR FLOW METER, he opened the air filter screws and increased the flap in the air flow meter with his finger.. It idles indefinitely.. can anybody suggest what my next step is or has any one come across the same problem?

Any info would be much appreciated.

Thanks  

Answer
So, your Miata is in a funk? Well, I would look at the air meter as well, and also the throttle position sensor.
Getting a new vane air meter is not a bad idea even if it is not bad, you have no idea how many times it has been filled full of grunge by a worn out air filter.
The vane air meter can be checked by identifying the circuit ground in the plug during operation and the signal wire from the meter to the ECM. This can be found in you service manual. Using an inexpensive multi-meter, check the DC Voltage across those two wires. Then, move the flapper door by hand, slowly, to identify if it has any places where you loose the signal all together. If the signal is lost at any point in the doors traveler you will need a new meter.
The failure of vane air meters is fairly common. They are found in Jaguar, Ford, Toyota, Mazda, Mercury, Merkur, VW, Porsche, and others. They are considered a poor excuse for an air meter and for those who are capable; they are removed and fitted with a MAP sensor and an aftermarket ECM that can be programmed to suit the car. It's a huge deal to go that far, but you can get another air flow meter and probably solve this problem. Just remember to keep a good quality and regularly changed air filter in it and it should last a while.

Regards,


John