Eunos Juddering Engine only on start from warm
Discussion
Hi
I have owned my MK1 Eunons for nearly a year. Since then I have had new cambelt, coil pack with HT leads and full service including replacement of spark plugs and all filters.
Since the arrival of the warm weather my car has continued to run fine apart from when it is turned off for say 5 - 10 minutes (just popping into shop etc). Then, when I return to start the car, it judders quite violently and sounds like it is about to stall but never does. I have tried turning off and starting again but it is just the same so I drive off and the juddering stops within about 30 seconds.
Given that I seem to have had all the relevant parts replaced does anybody have any ideas as to what the problem might be please?
I have owned my MK1 Eunons for nearly a year. Since then I have had new cambelt, coil pack with HT leads and full service including replacement of spark plugs and all filters.
Since the arrival of the warm weather my car has continued to run fine apart from when it is turned off for say 5 - 10 minutes (just popping into shop etc). Then, when I return to start the car, it judders quite violently and sounds like it is about to stall but never does. I have tried turning off and starting again but it is just the same so I drive off and the juddering stops within about 30 seconds.
Given that I seem to have had all the relevant parts replaced does anybody have any ideas as to what the problem might be please?
Even though they've recently been changed - could it not be the coil pack?
I have an identical problem on my 10 AE, starts fine from cold and usually fine from hot.
Start it from warm (or when it's been sat in the sun) and it will only run on 2 cylinders, it's driveable, but very low power and a strong smell of fuel.
After about 30 seconds or so the other cylinders kick in and it's back to normal.
It did it when I started it over the weekend (had been sat in sun) so I popped around the hood and started pulling HT leads off of the plugs. Pulled the one nearest me and no change to the engine noise.
Put it back and pulled the lead for the next cylinder along - engine tried to stall.
Put that one back and tried the next one, car tried to stall.
Put that one back and tried the last one (closest to firewall) - no change to engine noise.
Left that one off and pulled the lead off the cylinder closest to me again, no change to engine noise.
So, I'm assuming those two cylinders are fed by the same coil pack and it's a coil pack issue. This is further supported by some information over on Miata.net - apparently the coil packs are affected by temperature and weak ones don't work too well when they're hot - which explains why the OP has issues on warm start (engine heating engine bay whilst stationary) and it goes when moving (airflow/fan cooling engine bay).
Having said that, the Mk 1s have batch ignition, don't they - so it could also be an electrical/ECU problem?
I have an identical problem on my 10 AE, starts fine from cold and usually fine from hot.
Start it from warm (or when it's been sat in the sun) and it will only run on 2 cylinders, it's driveable, but very low power and a strong smell of fuel.
After about 30 seconds or so the other cylinders kick in and it's back to normal.
It did it when I started it over the weekend (had been sat in sun) so I popped around the hood and started pulling HT leads off of the plugs. Pulled the one nearest me and no change to the engine noise.
Put it back and pulled the lead for the next cylinder along - engine tried to stall.
Put that one back and tried the next one, car tried to stall.
Put that one back and tried the last one (closest to firewall) - no change to engine noise.
Left that one off and pulled the lead off the cylinder closest to me again, no change to engine noise.
So, I'm assuming those two cylinders are fed by the same coil pack and it's a coil pack issue. This is further supported by some information over on Miata.net - apparently the coil packs are affected by temperature and weak ones don't work too well when they're hot - which explains why the OP has issues on warm start (engine heating engine bay whilst stationary) and it goes when moving (airflow/fan cooling engine bay).
Having said that, the Mk 1s have batch ignition, don't they - so it could also be an electrical/ECU problem?
Edited by youngsyr on Monday 9th May 15:44
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