MR2 Roadster - A Tale Of Woe, Maybe...
Discussion
As Alice Cooper once said, welcome to my nightmare!
The story goes like this.
My only car for the last four and a half years has been my Nissan 350Z, which has been a wonderful car.
Until a year or so ago my other half owned a Toyota MR2 Roadster, which was also a wonderful car, and I always thoroughly enjoyed driving it.
She now has a GT86, and we were talking the other night about how it used to be nice going out on a warm summer night with the roof down.
I started looking at MR2 Roadsters for sale, and one in particular caught my eye.
A few days later, one bid on ebay with a few seconds to go, and I'd won the bidding on a year 2,000 MR2, in bright green with black leather, air con, a hard top, M.O.T., and all for £922.
Great, a bit of fun in an open top car for the summer, maybe tidy it up a bit and sell it later and, who knows, maybe even make a few quid..?
A 500 mile round trip from Kent to Yorkshire and back on bank holiday Monday ensued.
The car was as described, not perfect, but a good useable car, it all checked out ok.
The first 60 or so miles home, great, a few things to look at, a bit of wheel wobble around 65-75mph, and a very slight vagueness to the steering, stuff that I'm fine with checking out and dealing with.
Then, in torrential rain on the motorway, was that a little cough..?
Ooh, it's done it again. Oh, the engine light flickered then.
Maybe some of the heavy rain has got to a sensor, or a coil is a bit ropey, car still pulls ok just a slight hesitation on part throttle. A few times, it seemed to clear, the engine light went out and it felt ok.
I'll check that out when I get home.
And here it is at home.
Despite the misfire I was quietly feeling a bit smug, in a Mike Brewer kind of way, having bagged such a bargain!
A good service and a set of spark plugs and this thing will be sweet as a nut, 'old owt yer 'and, etc.
I plugged in a code reader which told me misfire on cylinders 3 and 4.
Hmm, ok, probably not too much to worry about, but I'll check it out very soon.
An hour or so later I went to go and pick a mate up, about a 3 mile round trip.
Started the car, KNOCK KNOCK KNOCK KNOCK KNOCK etc.
Whoa! That's not good, sounds like big end knock! Switch engine off.
Went to the pub.
Anyone who knows these cars well will probably by now be thinking, the pre-cats have broken up.
The pre-cats are basically like two small catalytic converters in the manifold before the main cat that absorb noxious stuff and make them legible in California for lower tax, or something.
Early Mk3 MR2s have been known to let oil past the oil control rings on the pistons, and oily exhaust gas gets onto the pre-cats. These then start to disintegrate, and thanks to an exhaust gas recirculation system, the bits of ceramic and whatever else get pumped right back into the engine, with terrible consequences.
So, next evening after work, I got home and started checking things out.
First, I thought I'd do a compression test, before draining the oil to do other checks.
First two spark plugs out, and yeah, not much to worry about here;
Next two spark plugs out:
Plenty to worry about here!
So, thinking I've heard big end knock, my next step was drain the oil, take the oil filter off and cut it open.
No signs of sparkly big end bearing in there.
I then took the exhaust manifold with pre-cats off, oxygen sensors out, and looked at the pre-cats. No signs of those falling apart.
I've been busy today but tomorrow I'm going to take the cam cover off and carry out a cylinder leak down test. And depending on the outcome of that I might take the sump off and check the big end bearings.
At the moment I'm suspecting a bent valve(s) caused by spark plug debris.
But if it is just a simple spark plug failure, how f
king unlucky is that!!? 256 miles is all I've driven in it, and I was going to replace them anyway!
I'll update this sorry saga when I know more, just in case anyone gives a fk! 
The story goes like this.
My only car for the last four and a half years has been my Nissan 350Z, which has been a wonderful car.
Until a year or so ago my other half owned a Toyota MR2 Roadster, which was also a wonderful car, and I always thoroughly enjoyed driving it.
She now has a GT86, and we were talking the other night about how it used to be nice going out on a warm summer night with the roof down.
I started looking at MR2 Roadsters for sale, and one in particular caught my eye.
A few days later, one bid on ebay with a few seconds to go, and I'd won the bidding on a year 2,000 MR2, in bright green with black leather, air con, a hard top, M.O.T., and all for £922.
Great, a bit of fun in an open top car for the summer, maybe tidy it up a bit and sell it later and, who knows, maybe even make a few quid..?
A 500 mile round trip from Kent to Yorkshire and back on bank holiday Monday ensued.
The car was as described, not perfect, but a good useable car, it all checked out ok.
The first 60 or so miles home, great, a few things to look at, a bit of wheel wobble around 65-75mph, and a very slight vagueness to the steering, stuff that I'm fine with checking out and dealing with.
Then, in torrential rain on the motorway, was that a little cough..?
Ooh, it's done it again. Oh, the engine light flickered then.
Maybe some of the heavy rain has got to a sensor, or a coil is a bit ropey, car still pulls ok just a slight hesitation on part throttle. A few times, it seemed to clear, the engine light went out and it felt ok.
I'll check that out when I get home.
And here it is at home.
Despite the misfire I was quietly feeling a bit smug, in a Mike Brewer kind of way, having bagged such a bargain!
A good service and a set of spark plugs and this thing will be sweet as a nut, 'old owt yer 'and, etc.
I plugged in a code reader which told me misfire on cylinders 3 and 4.
Hmm, ok, probably not too much to worry about, but I'll check it out very soon.
An hour or so later I went to go and pick a mate up, about a 3 mile round trip.
Started the car, KNOCK KNOCK KNOCK KNOCK KNOCK etc.
Whoa! That's not good, sounds like big end knock! Switch engine off.
Went to the pub.
Anyone who knows these cars well will probably by now be thinking, the pre-cats have broken up.
The pre-cats are basically like two small catalytic converters in the manifold before the main cat that absorb noxious stuff and make them legible in California for lower tax, or something.
Early Mk3 MR2s have been known to let oil past the oil control rings on the pistons, and oily exhaust gas gets onto the pre-cats. These then start to disintegrate, and thanks to an exhaust gas recirculation system, the bits of ceramic and whatever else get pumped right back into the engine, with terrible consequences.
So, next evening after work, I got home and started checking things out.
First, I thought I'd do a compression test, before draining the oil to do other checks.
First two spark plugs out, and yeah, not much to worry about here;
Next two spark plugs out:
Plenty to worry about here!
So, thinking I've heard big end knock, my next step was drain the oil, take the oil filter off and cut it open.
No signs of sparkly big end bearing in there.
I then took the exhaust manifold with pre-cats off, oxygen sensors out, and looked at the pre-cats. No signs of those falling apart.
I've been busy today but tomorrow I'm going to take the cam cover off and carry out a cylinder leak down test. And depending on the outcome of that I might take the sump off and check the big end bearings.
At the moment I'm suspecting a bent valve(s) caused by spark plug debris.
But if it is just a simple spark plug failure, how f
king unlucky is that!!? 256 miles is all I've driven in it, and I was going to replace them anyway! I'll update this sorry saga when I know more, just in case anyone gives a f
k! 
I miss having a summer toy and having had 2 mx5's I wanted another but all the cheap ones are rusty heaps. My next plan was one of these since they've reached a level where you can lose nothing on depreciation so I'm certainly interested.
It could be a nice cheap summer toy but a few engine related things scare me, the pre-cat issue being one of them. I've seen mention of head gasket on some models too. Still tempted to take a risk because it won't be the main car and would give me the excuse I need to sort out the garage. The problem is my budget starts at £1000 and by the time I'm finished looking it's at £5000 and I'm looking at Boxsters and missing the original point
It could be a nice cheap summer toy but a few engine related things scare me, the pre-cat issue being one of them. I've seen mention of head gasket on some models too. Still tempted to take a risk because it won't be the main car and would give me the excuse I need to sort out the garage. The problem is my budget starts at £1000 and by the time I'm finished looking it's at £5000 and I'm looking at Boxsters and missing the original point
poing said:
I miss having a summer toy and having had 2 mx5's I wanted another but all the cheap ones are rusty heaps. My next plan was one of these since they've reached a level where you can lose nothing on depreciation so I'm certainly interested.
It could be a nice cheap summer toy but a few engine related things scare me, the pre-cat issue being one of them. I've seen mention of head gasket on some models too. Still tempted to take a risk because it won't be the main car and would give me the excuse I need to sort out the garage. The problem is my budget starts at £1000 and by the time I'm finished looking it's at £5000 and I'm looking at Boxsters and missing the original point
They do seem to have hit pretty much rock bottom on value.It could be a nice cheap summer toy but a few engine related things scare me, the pre-cat issue being one of them. I've seen mention of head gasket on some models too. Still tempted to take a risk because it won't be the main car and would give me the excuse I need to sort out the garage. The problem is my budget starts at £1000 and by the time I'm finished looking it's at £5000 and I'm looking at Boxsters and missing the original point
I've not heard of head gasket issues, but I've read that big end bearings can start to knock, an easy fix if you catch it early enough.
Seeing as I've already got my exhaust manifold off I'm going to smash the pre-cat stuff out of them before they go back on an engine.
Hammer and a screwdriver and maybe a blow out with a pressure washer and compressed air and that's that potential problem eliminated.
Post face lift cars are much less likely to suffer from this issue due to the revised oil control rings, so I've read.
And they have a six speed gearbox, nicer looking bumpers and lights and a limited slip diff, so they're the ones to go for.
You'll be lucky to get a decent facelift model for less than about £2,000, but it's still a fantastic car for the money, in my opinion.
Mr Tidy said:
Good luck with the test.
To be fair in the photo it looks a lovely car for the money - hope it isn't too major a fix.
Thanks!To be fair in the photo it looks a lovely car for the money - hope it isn't too major a fix.
I am a pessimist, so expecting the worst. That way, if it's not the worst I get a pleasant surprise!
It is a little tatty on the outside, but it will tidy up a bit, and I have a very good mate who is a car painter who will help me sort a few bits out (I look after his cars mechanically).
Even if I have to spend a few hundred on the engine, doing the work myself, and a couple of days sorting a few niggles out, I think it will still be a reasonably good car for the money.
Very worst case will be needing a replacement engine, but lets not get too into that thought just yet...
Are the two bad plugs from adjacent cylinders?
If so, by the look of the plugs I suspect that the head gasket may have failed in a big way between the two cylinders.
When this happens, burning gasses pass from one cylinder to the other which results in a very heavy combustion knock that sounds like big ends, so I think it's well worth checking the compressions first.
If so, by the look of the plugs I suspect that the head gasket may have failed in a big way between the two cylinders.
When this happens, burning gasses pass from one cylinder to the other which results in a very heavy combustion knock that sounds like big ends, so I think it's well worth checking the compressions first.
Yes, the plugs are from cylinders 3 and 4.
I hadn't thought of head gasket failure, that's quite interesting, and I won't rule it out, thanks for the suggestion.
These engines do have another feature, again for emissions control, where under certain conditions the variable cam timing creates exhaust gas scavenging between cylinders, so it's also possible that a failure in one cylinder has sent debris into another cylinder.
I will still do the leak down test first, as a major head gasket problem will still show up as something, and go from there.
I hadn't thought of head gasket failure, that's quite interesting, and I won't rule it out, thanks for the suggestion.
These engines do have another feature, again for emissions control, where under certain conditions the variable cam timing creates exhaust gas scavenging between cylinders, so it's also possible that a failure in one cylinder has sent debris into another cylinder.
I will still do the leak down test first, as a major head gasket problem will still show up as something, and go from there.
Edited by Martin350 on Saturday 7th May 23:59
The one thing that still baffles me the most at the moment is that one minute the engine had a bit of a misfire and a slightly lumpy idle, but really wasn't that bad.
The next time I started it up after an hour or so it had major death rattle.
The suddenness of the knocking noise is what I don't currently understand more than anything.
I was tempted to have a rant at the ebay seller, but at the moment I really don't think that this could have been predicted or known about, as it ran perfectly when I first picked it up.
The next time I started it up after an hour or so it had major death rattle.
The suddenness of the knocking noise is what I don't currently understand more than anything.
I was tempted to have a rant at the ebay seller, but at the moment I really don't think that this could have been predicted or known about, as it ran perfectly when I first picked it up.
Edited by Martin350 on Sunday 8th May 00:08
I may be wrong but my instinct says head gasket failure, that's after forty years as a motor mechanic or tech as they say now.
When the gasket fails in such a way that allows burning combustion gasses to pass from the firing cylinder to one that is on the compression stroke, massive pressure and temperatures are caused by the detonation that occurs.
This type of gasket failure happen very quickly and causes the engine to make a very loud combustion knock.
When the gasket fails in such a way that allows burning combustion gasses to pass from the firing cylinder to one that is on the compression stroke, massive pressure and temperatures are caused by the detonation that occurs.
This type of gasket failure happen very quickly and causes the engine to make a very loud combustion knock.
Edited by oakdale on Sunday 8th May 00:51
Today I took the cam cover off and carried out a cylinder leak down test, which revealed, surprisingly, nothing much at all.
As I've already mentioned, the pre-cats appeared to still be intact;
But I took a hammer and a screwdriver to them anyway;
I'll clean the dust out tomorrow with a pressure washer and compressed air, but that's that potential problem disposed of!
I then wrestled the sump off, it's not got a gasket but some very effective silicone type sealant stuff, and removed one of the big end caps (I ran out of time then), and again, not much to report here.
I'll take the other three off tomorrow and have a look, I'm now not expecting to find much there, but it doesn't take long to check them out.
So basically, it's still a bit of a mystery!
As I've already mentioned, the pre-cats appeared to still be intact;
But I took a hammer and a screwdriver to them anyway;
I'll clean the dust out tomorrow with a pressure washer and compressed air, but that's that potential problem disposed of!
I then wrestled the sump off, it's not got a gasket but some very effective silicone type sealant stuff, and removed one of the big end caps (I ran out of time then), and again, not much to report here.
I'll take the other three off tomorrow and have a look, I'm now not expecting to find much there, but it doesn't take long to check them out.
So basically, it's still a bit of a mystery!
Interesting read, it is somewhat baffling that all these modern emission gizmos make engines so fragile and just overcomplicated. I shudder to think about how maintaining one's own car will be once all the simpler stuff is on the scrapyard.
I hope it turns out to be an easy fix, but its looking like a head-off job right now from my point of view
I hope it turns out to be an easy fix, but its looking like a head-off job right now from my point of view
Gassing Station | Readers' Cars | Top of Page | What's New | My Stuff