Hi all,
I may have the opportunity to buy a 99 reg mk2 mx-5 that has been sat for about 3 years and is apparantly in need of a new ecu and keys due to water ingress into the passenger footwell, i am waiting to find out more info but i am interested to find out how much this could potentially cost to repair ?
Any help is much appreciated !
Potentially a lot of time money and frustration. There are so many good 5’s to choose from that one that has stood for 3 years with water and a duff ecu would be my last pick. There’ll be loads of other issues with corrosion, brakes, tyres, battery, exhaust, smelly carpets, spiders 
etc. I’d give it a big swerve and find one that’s at least running so you can evaluate it properly and enjoy the summer 
I thought that might be the answer 
I dont know that much about the car at the moment, my girlfriends dad is a car dealer and he mentioned to me that he knew of one that was going cheap (probably about 400-500 quid). I was just trying to establish if the numbers would stack up if the repair was just the ecu and new keys. I think i had my wheeler deeler head on 
!
The car would need a full service and probably a cambelt as well plus other bits and bobs…i do know from previous experience that ecu’s can be a real arse to sort out (had an old astra that had brain problems), but i did figure that the parts would be cheaper for the mk 2 now plus i would hopefully do alot myself if possible. But your probably right…too much hastle !!
Mmm, sorry to be negative, it’s only my view, and don’t let me put you off if you’re keen and know MX5’s well, but the money and time can certainly rack up on a car like this. I take the view that if there really was an easy fix the owner would have done it and sold it running with MOT etc. When you do get a decent runner you’ll still find enough things to do I’m sure 
If she is only going for 400 and the body is soild. i would grab her,nice project, i’ll have her, send me a P.M
If you don’t know these roadsters, it could become a very dear buy as richard as said, she will need a lot of work to get her fit for the road now, costs can be high,if you do not know what you are dealing with, and doing.
Richard you have a P.M
M-m
I am new to mx-5’s and i am currently looking for my first one, i was just thinking that this could potentially be a good project for me to learn alot more about them. I see what your both saying though, it sounds like it could end up being alot of work and hastle for a newbe like me ! not that i am not willing to get my hands dirty though !
As for the price i haven’t seen the car yet and know very little about it, and i think that 400-500 may have been a family discounted price but not sure. The only thing i’ve been told is it needs new ecu and keys. I don’t even know the millage. When i get a look at her ill try and get some pictures and an idea what he’ll want for it. I’ll bear you in mind though Mazda-mender
If it’s reasonably well together, that’s an ok price. A breaker would pay nearly that much for a write off…
thanks Wayne
That is what I thought but I was unsure of the rough cost of a new ecu, locks and keys so I can get an idea of how much it could potentially cost me. Although I am inexperienced I do know a very good auto electrician and mechanic who may be able to help, and with a little help from the forum I hoped it could be a possiblility but as I said before I need to see the car and get an idea what else is wrong with it.
Although I have been told that it needs a new ecu that might not be the case !
Are the keys pretty straight forward to get or do they have to be purchased from Mazda for huge sums of cash ??
If you are looking at something to build yourself up on ,with these Mx/Roadsters then you need to start with a MK 1 to learn the robes, this Mk 2 will cost you to much money in the end as a learning curve, which sounds like you don’t have with the buget you are working with, your safer bet is a MK 1 to start with.
M-m
I have been looking at mk 1’s, just thought this sounded like a potential diamond in the rough. But I am aware that electrical problems can be a nightmare for an experienced person let alone a newbie ! Is this the sort of thing you go for ?
She would not be a problem for me,as i would of done and repaired everything that would or could be wrong with here, my costs would be low as i would more than likely have most of the parts sat here in the bat cave to attack her with.
M-m
This thread gives an indication of the cost of a new coded ECU:
http://www.mx5oc.co.uk/forum/forums/p/28934/198136.aspx#198136
I don’t know if a used Roadster ECU could be used; no immobiliser. I would have thought removal of the factory immobiliser would have all sorts of profound insurance implications, but I suppose all those owners with aftermarket programmable ECUs have a legit response.
I think BBR used to refurbish ECUs for Mazda; most of the ECU failures were due to dirty contacts it seems.
Buy the car - you will have fun dismantling to break, learning about the car and making some money. Assuming you have somewhere to work, you cannot go wrong for this price. As an earlier poster correctly said, no breaker would turn a MK2 away for £400.
If the car is solid with no other problems, the bits you require - correct ECU, immobiliser box, ignition, ignition coil, transponder keys, and all locks should be available for around £100. Make sure you get all the bits. I would also carefully check the loom near the ECU as water ingression can also damage the loom.
I would have an open mind on the car. MK1 and MK2 are similar in a lot of ways. No better way to learn about how a car works than to sympathetically take her apart. My problem is I always end up putting them back together again:-)
As I mentioned previously I have been looking for mk1’s only but when I heard about this my mind did start doing overtime !
I still haven’t heard back about the fine details, but it may be too good to be true ! I like the thought of breaking it if all else fails, how long would something like that take ?
Last year I thought my ECU (PCM btw) was shot, I rang Andrew at Autolink and he had one S/H Mk 2.5 PCM in stock, said it would be £500, but he had no immoboliser, he said if he had it would be another £250, so £750 for the two. The dealer price on the original post sounds about right, for a new unit at dealer prices - as someone on here said several years ago the cost was around £2000. Fortunately I later found that the main and room fuses were both blown, I won’t go into why, but fifteen quid sorted it.
Having helped fit an FM ECU I reckon it would take at least 3" (75mm) of standing water in the passenger footwell to eventually reach the PCM, assuming it gets by the cover gasket, so I’m always sceptical when someone assumes because he got water or just damp carpet in the footwell that the PCM is shot. Restoration of a car (if you have a life) is a two - three year project unless you are a skilled mechanic, and have the time to do remedial work on a daily basis. I would say go for a running car that needs some TLC, then you can still drive it - assuming it’s roadworthy, and spend time on minor restoration as and when it’s convenient. If restoration was easy, there’d be busy household garages on every street. It sounds a good idea, but I forget how many half restored cars I’ve seen for sale over the years, and that includes kit cars.
Thats interesting that you say that you’d need 3 inches of water ! that is alot of standing water to get into the footwell. Does make you think if it is the PCM or something more straight forward ? Is there a more complicated key setup on the 2.5’s than an early mk2 ?
I’ve mananged to find out that the price is not 500 quid, looks like the bloke wants to closer to a grand for it !
Re key locking and remote entry - AFAIK the Mk2 and Mk2.5 have the same system, but the PCM’s are slightly different, as the Mk2.5 1.8 version has added VVT control.
I need to qualify that statement I made about the depth of water, I haven’t poured water in my or anyones car to find out, the 3" is a guess, based on the fact that the PCM is located under the sloping part of the footwell about half way up, in a compartment about 10-12" square and covered with a gasketed lid which is also permanently fixed with ‘break-off’ bolt heads’ which have to be chiseled to make a slot with which they can be unscrewed.
Also - I’m assuming the car is on a level base, if it’s facing downhill, then the story could be worse! However, if there was water in the footwell, even if it didn’t reach the PCM enclosure, it won’t do the floor any good, and particularly seat mounts, which might raise safety issues. If - as you say, the seller now wants a thousand for it, then I personally would want to see the engine running, and a new battery fitted, and while they won’t like it, either an MOT and Tax if it’s driveable, or you’ll have the added expense of getting a truck and trailer to shift it. Afer three years non-use, I wouldn’t like to drive it without an MOT pass.(Even with a trade plate)
As you say it’s been stood for three years then I would make the assumption that you may have to spend several thousand on it to cover potential problems, while you can buy a running Mk2 for less than the eventual cost - check out the cars for sale on here, ebay and privately. My advice would be - walk away, and find a roadworthy car, Mk1 or Mk 2. Dreams are one thing,. reality is often harder to bear, but you should always face reality, as it’s the only sensible option.
I’m not recomending them - though some local members would - but there’s an outfit up here at Shardlow just outside Derby who buy scrapped Mx’s (usually insurance write-offs) who then repair them and resell them in a roadworthy condition. They only do this if the basic car is repairable, otherwise they break them for spares, but a comparitively new car can be bought for far less than the market value of a good car and it’s worth considering. Most write-offs are due to front or rear end collisions, and as long as the rest of the car is all right, then it makes sense to repair the damage and move them back into the market. They also sell spares, but not front and rear ends, as they need them for the next repair! I’m told they currently have a Mk3 CC for far less than the market cost, though I’m not suggesting you go for it. (it may be sold already anyway!)
They are - P H Sportscars, British Waterways Yard, Cavendish Bridge, Derby, DE72 2HL 01332 799298
Footnote - PCM is short for Powertrain Control Module, the Mazda equivalent to ECU.
Here’s a Mk1 with an honest write up, some TLC needed, but taxed and MOT’d to November anyway, just to start you off -