Mazda MX5 1.6 - intermittent engine cut-out

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Mon 19 Jul 2010 22:21
Mazda MX5 1.6 - intermittent engine cut-out - Jon P

One day my 1996 Mazda MX5 Monaco (that's the options-free economy 1.6 model) will do a faultless 500-mile round trip and the following day it will break down every 300 yards.

The engine will just stop running whether it is ticking over or on the move.

The rev-counter needle will drop to zero instantaneously accompanied by a big fat click emanating from somewhere behind the main instrument binnacle directly in front of the driver.

The engine may restart immediately. It may restart after several attempts. Or it may need a 3 minute rest. It will always restart at some time but I will be back to Square One within moments.

Before successfully restarting, the starter will turn the engine over but all it will be doing is rocking the engine around - you can just tell it is not interested in firing - until it fires and revs freely.

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Mon 19 Jul 2010 23:07
Mazda MX5 1.6 - intermittent engine cut-out - elekie&a/c doctor

Possible crank/engine speed sensor fault.Sits on front of engine down behind crank pulley.hth

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Tue 20 Jul 2010 08:43
Mazda MX5 1.6 - intermittent engine cut-out - Jon P

Dear doc

Is that the same as the crankshaft position sensor?

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Tue 20 Jul 2010 09:11
Mazda MX5 1.6 - intermittent engine cut-out - elekie&a/c doctor

Yes,that's the same part.I think they cost around £70

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Thu 22 Jul 2010 16:43
Mazda MX5 1.6 - intermittent engine cut-out - Jon P

Doc

Do you know if it is possible for my immobiliser system to be throwing up this problem? Could something be breaking down now and again while I am driving.

In the past I seem to recall being told that an immobiliser system was designed to actuate only when starting the engine initially, ie. it could not stop a car when it was in the outside lane ot a motorway.

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Thu 22 Jul 2010 17:26
Mazda MX5 1.6 - intermittent engine cut-out - ohsoslow

Have you checked that everything ignition related is connected properly......supply to and from the coil pack at the back of the engine block for instance, or engine earth connections?

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Fri 23 Jul 2010 03:51
Mazda MX5 1.6 - intermittent engine cut-out - 1litregolfeater

I'm not a mazda expert by any stretch but weren't the engines from this time known for dodgy dizzies.

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Wed 28 Jul 2010 23:37
Mazda MX5 1.6 - intermittent engine cut-out - Jon P

Ohsoslow; I've had the best minds in my street on this problem from early on and there is definitely nothing hanging off or unplugged. Cheers anyway.

1litregolfeater; I've just had the crank speed sensor and the ignition module replaced. No change. Problem still apparent. Ho hum.

HELP. Anyone out there familiar with ECU/immobiliser problems relating to late MK1 MX5s? (NB. Mine is the one with the immobiliser chip thingy incorporated into the key.)

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Thu 29 Jul 2010 21:42
Mazda MX5 1.6 - intermittent engine cut-out - sandy56

have you been to a good garage and aksed them to read the ECU and see what faults are reported?

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Thu 29 Jul 2010 22:31
Mazda MX5 1.6 - intermittent engine cut-out - Railroad.

It's worth checking the ignition module which is located inside the distributor (depending on variant). It will be banana shaped and fixes to the base plate by a couple of screws. Between the module and the base plate should be a smear of heat insulating compound. Over time it hardens and the module gets hot and fails. It will often work again when it cools down. This sounds like your problem. Remove the module and clean the underside of it. Then place a smear of compound on it and re-fit.

The only snag here is I don't know where you can get some. A new module will often come with a sachet in the box. I used to keep all the partially used sachets for this very purpose.....

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Sat 31 Jul 2010 15:18
Mazda MX5 1.6 - intermittent engine cut-out - Jon P

Sandy 56, My car is a year too old to benefit from the full diagnostic facilities - I am being seriously held back by that. I have, though, booked the car in for a fresh look by a reputed auto-electrician next Tuesday. I will post their findings.

Railroad, Good call. I have had the ignition module replaced - it was on the inner wing. Unless it was a duff new part, it has had no effect. Thanks anyway.

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Mon 2 Aug 2010 18:43
Mazda MX5 1.6 - intermittent engine cut-out - sumpnut

It's rather a long shot but the main relay is behind the bulkhead in front of the driver and may cause the click you hear, should it drop out.

Check connections and feed to the fuse, relay box and the relay.

Good luck

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Sat 10 Sep 2011 01:55
Mazda MX5 1.6 - intermittent engine cut-out - doctormx5

Its sweet to see so many caring responses to your MX5 problem. Having said that, I sometimes wonder whether such deluges of well-meant advise actually help people with their technical problems or slow down their resolution. Perhaps in the end a forum like this is for people who need a hand to hold while they muster the courage to call a professional. Now I think about it - I've been there too.

Your car probably needed a new cam angle sensor.

Just for the record (I reference a previous response) your car could not possible have had a crank sensor fault because it does not have a crank sensor. Relays? modules? no, and no. Earth to rear of power plant frame is a very remote possibility.

Do you know your car has onboard (or SELF) diagnosis. Stick a diode in the plug and count the fault code off.

Edited by doctormx5 on 10/09/2011 at 02:00

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