mx5cartalk.com

Hi All...

I know this is a weird question, but my girlfriend has an Astina, pop up headlight model, i think its a 1991 or something, 150 000km.

Either way, as far as i know it has the same block as the MX5, but with a SOHC.

Anyways, the problem is thus:

When the motor is under load, ie, trying to accelerate up a hill in fourth, the motor starts to choke and die, it actually feels like the clutch is slipping, but its not because the clutch is only 5000km old.

In the time she has owned it we have:

Replaced Spark Plugs
Replaced Clutch, Pressure Plate and Bearing
Replaced Radiator
Replaced Air Filter
Continuously maintained it and changed the oil every 5000km.

Any clues as to what may be causing it? My best guess is something electrical, ie, leads or maybe a coil pack (is it coil pack or distributer in these things?) However, we are thinking of selling it sooner rather than later and dont want to spend money fixing a car we may not really use that much more. (plus the car is only worth about $4000 since the mazda red has faded to the mazda pink and splodgey white).

What do you guys think is the problem?

Carburettor or FI? Distributor and coil or coil packs and ignitors?

Without knowing any of the above:

Auto choke problem (stuck closed or partly closed)
Stuffed carby accelerator pump
Carby blockages
Incorrect carby mixture setting

Blocked fuel filter (check fuel gauge for quantity too )
Fuel pump not working properly

Coil, plugs, leads, timing

When you say it feels like the clutch is slipping, is it a case of you are driving up a hill in 4th and the engine revs go up with no increase in speed?

If Not, have you checked things like fuel filter, all the electrical grounds on the motor, ignition timing.

Does the motor rev out smoothly and cleanly in neutral? In the lower gears? Any other signs of hesitation under load?

That mazda pink will turn red again with a good buffing.

john!

try to cancel out the most simple things first ie: fuel filter, fuel, spark etc.

The motor is not accelerating whilst the car is not, aka a worn clutch, more like a missfire when the motor is under load.

Maybe a little more clarification here:

Is Fuel Injected
Does rev out nicely in netural (or lower ratios) and is not rough
Havent check fuel filters, does have a full tank of fuel...

My suspicions are the coil packs, but i am unsure as to the symptoms of stuffed coils?

Try new plug leads and plugs.

I used to own a 91 Astina, actually. They're a BP-based SOHC EFI engine.

If I were you, I'd check the strength of the spark (by eye - put the lead on the plug, pull the plug out and ground the plug on the cam cover/engine hook/other good ground).

An engine that misfires under load can be caused by:
* Plugs
* Plug leads
* Distributor
* AFM

I'd check those, in that order.

Thanks Guys...

Will have a play and see what happens...