MX5 Won't start or runs very roughly - suggestions?
Discussion
Hello all,
I hope you can help with a problem on my wife's car. It may actually be 2 problems but I am rather hoping they are connected...
1 On 4 different occasions in the last few months the car will simply not start. The starter motor does not turn and I am pretty sure the immobiliser is not playing up. We try it a few times and then give up... Then, after a wait of anything up to a couple of hours, it will start with no apparent problems at all. Funnily enough, the mrs is scared to take it anywhere in case it won't start and she is stranded on her own. We have had diagnostics done by Mazda (which showed nothing) and also had it looked at three times, but the fault could not be replicated. One mechanic said it was the immobiliser causing it; one said it was a loose battery connection; one didn't have a clue! It is very frustrating as we can no longer trust the car and have had to call a breakdown service out more than once, but no-one can tell us what is wrong with it.
We have tried to spot a pattern in when it does this - it seems most likely to do it when it is wet and has been used for a short journey. However, it is by no means confined to doing it in these circumstances. I have done a good check of the engine bay and it doesn't seem to have any loose wires/ dodgy plugs/ excessive water ingress etc...
2 On other occasions, the car WILL start but runs roughly - almost as though the plugs are not 'catching' properly (sorry for the lack of correct engineering terminology!). The car can be driven but is very, very low on power and will often stall when it comes to a halt. I have seen the thread leading to this advice - http://www.miata.net/garage/KnowYourCar/S7_Idle.ht... - so will give it a try, but can't help feeling this problem might be connected to the non-starting issue. In our case, the car will not idle properly and the revs bounce up and down, occasionally causing it to stall if no power is apllied. It ususally sorts itself out quite quickly, but on occasion has taken up to 30 mins plus.
Any thought or suggestion on this issue would be very welcome indeed, as I don't really know where to go from here!
Many thanks,
Kev.
I hope you can help with a problem on my wife's car. It may actually be 2 problems but I am rather hoping they are connected...
1 On 4 different occasions in the last few months the car will simply not start. The starter motor does not turn and I am pretty sure the immobiliser is not playing up. We try it a few times and then give up... Then, after a wait of anything up to a couple of hours, it will start with no apparent problems at all. Funnily enough, the mrs is scared to take it anywhere in case it won't start and she is stranded on her own. We have had diagnostics done by Mazda (which showed nothing) and also had it looked at three times, but the fault could not be replicated. One mechanic said it was the immobiliser causing it; one said it was a loose battery connection; one didn't have a clue! It is very frustrating as we can no longer trust the car and have had to call a breakdown service out more than once, but no-one can tell us what is wrong with it.
We have tried to spot a pattern in when it does this - it seems most likely to do it when it is wet and has been used for a short journey. However, it is by no means confined to doing it in these circumstances. I have done a good check of the engine bay and it doesn't seem to have any loose wires/ dodgy plugs/ excessive water ingress etc...
2 On other occasions, the car WILL start but runs roughly - almost as though the plugs are not 'catching' properly (sorry for the lack of correct engineering terminology!). The car can be driven but is very, very low on power and will often stall when it comes to a halt. I have seen the thread leading to this advice - http://www.miata.net/garage/KnowYourCar/S7_Idle.ht... - so will give it a try, but can't help feeling this problem might be connected to the non-starting issue. In our case, the car will not idle properly and the revs bounce up and down, occasionally causing it to stall if no power is apllied. It ususally sorts itself out quite quickly, but on occasion has taken up to 30 mins plus.
Any thought or suggestion on this issue would be very welcome indeed, as I don't really know where to go from here!
Many thanks,
Kev.
Hi,
You don't mention age/mileage of car but from what you do say, I'd check that the battery connections are tight/clean and the earth connection to the body, and the same with the connections to the main power lead through to the starter motor. If they are all tight and clean, I might start suspecting a dodgy battery cell or two.
As to your rough idle, depending on when they were last changed, the coil packs, leads and plugs must be a favourite.
MG Mark
You don't mention age/mileage of car but from what you do say, I'd check that the battery connections are tight/clean and the earth connection to the body, and the same with the connections to the main power lead through to the starter motor. If they are all tight and clean, I might start suspecting a dodgy battery cell or two.
As to your rough idle, depending on when they were last changed, the coil packs, leads and plugs must be a favourite.
MG Mark
I know you are desperately trying not to point the finger at this but it does seem to me like the immobiliser has a fault & damp conditions is one of the things that will highlight this & make matters worse.
The immobiliser is the ONLY electrical device that will stop the starter from turning over, other than a faulty soleniod, dead battery or bad battery earth (all of which should have been picked up in a Masda diagnostic) & a bad battery earth will not make the engine misfire or run rough - so it has to be the immobiliser IMHO.
ETA: The only other thing that could stop the starter & interfere with the engines smooth running is the ignition barrel, but I've never heard this happen before
The immobiliser is the ONLY electrical device that will stop the starter from turning over, other than a faulty soleniod, dead battery or bad battery earth (all of which should have been picked up in a Masda diagnostic) & a bad battery earth will not make the engine misfire or run rough - so it has to be the immobiliser IMHO.
ETA: The only other thing that could stop the starter & interfere with the engines smooth running is the ignition barrel, but I've never heard this happen before
Edited by Quick silver on Monday 31st August 18:14
Quick silver said:
OnlyMX5ives said:
Unless you have an aftermarket Immob. its not that.
Most likely a bad earth.
Where are you based ?
What would make you think it was a bad earth?....for this to happen it would have to be common to both starter & ignition?Most likely a bad earth.
Where are you based ?
OnlyMX5ives said:
Quick silver said:
OnlyMX5ives said:
Unless you have an aftermarket Immob. its not that.
Most likely a bad earth.
Where are you based ?
What would make you think it was a bad earth?....for this to happen it would have to be common to both starter & ignition?Most likely a bad earth.
Where are you based ?
All,
Many thanks for your input so far - most helpful. Some general info on the car. It is a mid-2000 ('W' reg) with approx 42,000 miles on the clock, based in Cirencester, Gloucestershire.
When my wife gets home from work I will check the battery over. I do not know if it is an original battery or not, but I am pretty sure we checked it over thoroughly when this first happened and it seemed fine.
As for the immobiliser, your insights are pushing me towards the conclusion that it is indeed the culprit. I do not think it was an aftermarket addition. However, I do have an inkling that it was not a standard system. (It is a Toad system that used to run in conjunction with the Toad alarm, until the alarm itself gave up.. You know the standard problem - alarm goes off uncontrollably the night before the wedding, keeping the poor bride up until 3 am...!! Forgot to mention that... The fitting certificate of the Toad is dated as the same day as first registration of the car. Perhaps it was an optional extra.)
Thanks very much again - I hope this gives you something more to go on!!
Kev
Many thanks for your input so far - most helpful. Some general info on the car. It is a mid-2000 ('W' reg) with approx 42,000 miles on the clock, based in Cirencester, Gloucestershire.
When my wife gets home from work I will check the battery over. I do not know if it is an original battery or not, but I am pretty sure we checked it over thoroughly when this first happened and it seemed fine.
As for the immobiliser, your insights are pushing me towards the conclusion that it is indeed the culprit. I do not think it was an aftermarket addition. However, I do have an inkling that it was not a standard system. (It is a Toad system that used to run in conjunction with the Toad alarm, until the alarm itself gave up.. You know the standard problem - alarm goes off uncontrollably the night before the wedding, keeping the poor bride up until 3 am...!! Forgot to mention that... The fitting certificate of the Toad is dated as the same day as first registration of the car. Perhaps it was an optional extra.)
Thanks very much again - I hope this gives you something more to go on!!
Kev
Hmm - the joys of non-standard electronics - not aware that a Toad system was fitted as standard, and if it is not complete and it is around 10 years old, then that may well be your culprit, as it probably won't show up as a fault code. Aside from checking earths, get what is left of it removed and see what happens...
MG Mark
MG Mark
So, I am going to get the immobiliser ripped out and see whee we go from there. An associated question, though - given that aftermarket systems seem to cause so much trouble, would be wise to replace it or not? I tihnk we'd rather have one than not - anyone know any reliable systems we could look at fitting that won't break the bank?
Thanks,
Kev.
Thanks,
Kev.
Really depends on what you want it to do - i.e. how you use the car, in what environments, and what circumstances you want to protect against. If your car is so attractive to a professional, they will manage to spirit it away whatever you fit to it.
Equally, you can make it quite unattractive to the opportunist with the likes of warning stickers, a flashing red LED on the dashboard, using a decent steering lock, and fitting a hidden switch that is connected into something that will prevent it starting or running, such as an ignition, fuel or starter circuit. The switch can also be wired such that if a door courtesy light switch is made when a door is opened, then the horn sounds continously. Can achieve much the same effect at a fraction of the price and complexity....
MG Mark
Equally, you can make it quite unattractive to the opportunist with the likes of warning stickers, a flashing red LED on the dashboard, using a decent steering lock, and fitting a hidden switch that is connected into something that will prevent it starting or running, such as an ignition, fuel or starter circuit. The switch can also be wired such that if a door courtesy light switch is made when a door is opened, then the horn sounds continously. Can achieve much the same effect at a fraction of the price and complexity....
MG Mark
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