Our Cars : Mike’s Rover 75 loses its spark

Once, twice, three times a breakdown

With a Volkswagen Golf Mk 6 and my rechargeable LED worklamp for illumination at 5.30 this morning in -5 temperatures, a new relay is inserted into the fusebox.

I have lost count the numbers of times that many people (including myself) bang on about servicing your car regularly and correctly in order to get the very best compromise of economy and reliability. It is, of course, completely true that if you never lift the bonnet, your car will simply wither and die slowly, like an ignored house plant. So, armed with a little time off and some dry weather the Project 75 was treated to a little love.

To be fair, it only required a lube service and general kick of the tyres, as everything else was dealt with this time last year. However, I wanted to be sure everything was as ship shape as can be before the cold sets in – rolling around on the drive in a foot of snow is no fun, trust me!

Anyway, up on blocks it went – the old oil was flushed through with the aid of a litre of diesel and a lengthy period of fast idling, some new blood was transfused and a shiny new oil filter spun onto the K-Series oil pump housing. The brake pipes were re-greased followed with a good old fashioned ‘look see’ and that was it, off the stands and ready for whatever the English winter weather can throw at it – or so I thought.

Just a few days before a journey back to its birthplace (Longbridge), a familiar slight cough returned to perplex me and try my sanity. In a similar vain to old steam engine drivers being able to hear the loco speaking, I know right away when something is awry with the Rover – and something certainly was.

The last time a similar event happened, it was cured after a little tinkering on a T4 laptop but this time the little splutter was more pronounced and regular – especially when cold. On a return charter home it gave a god almighty cough only this time enough to illuminate the ECM lamp on the dash – at least now there would be a fault code to aid the diagnosis.

Sure as anything there was a stored code showing a malfunction of the upstream oxygen sensor, so I fitted a good working spare item which sadly required the butchering of a decent 22mm ring spanner with a hack saw in order to fit it and the code was cleared from the ECU. A road test followed and the car seemed to be okay for the time being at least but the joy of seeming success was to be shortlived.

The long drive up to Birmingham went without fuss but there was a noticeable lack of va-va-voom on the hilly parts of the M25 and M40. Yes… yes… I know my model has the poverty spec 120bhp 1.8-litre under the bonnet but, even so, there was certainly something holding a large proportion of those horses back. Also the fuel consumption was no where near as frugal as per the norm.

Later on that afternoon, I navigated a convoy of three to one of Birmingham’s Balti houses of repute after a trip to MG Motor UK’s factory at Longbridge and, when heading northbound on the A38 through Brum’s rush hour drudgery, a pronounced and rather violent misfire started. The later journey (following a great meal with excellent company) back to leafy Sussex went without fuss – well, that was until we got onto the M25 for the final furlong…

The second of three fault codes logged as a direct result of a faulty insulator on coil pack. Random multiple miss fire – Great!

After dropping my passenger off in Surrey, I made my way home along the back roads towards Gatwick when the stuttering and coughing got so bad, the ECM lamp was flashing and the car felt more like some kind of electronic bucking bronco – I pulled over quickly for further inspection.

Dipping into one’s pocket for a sensor or a spark plug is one thing, but I felt sick at the thought of a spiked catalytic converter. The code reader spoke of a random multiple misfire and an O2 sensor malfunction. Now the fault only occurred under mid or heavy throttle, so it seemed fairly obvious that something electrical on the ignition side was breaking down but it was after midnight and I was cold and tired.

I was, in part, minded to call out the RAC but that is the last resort as well as a massive dent in personal pride so I resumed my journey for the remaining 15 miles using the lightest of dabs on the loud pedal to avoid a machine gun sounding engine and a potential blown cat.

The following day, after a good night’s kip, I set upon righting the worrying wrongs with the car and started some initial digging about and routine investigation. A previous blog mentions about the changing of the coil packs, so imagine my surprise to find the coil pack on cylinder number three to be tracking voltage from the insulator that fits over the spark plug. A rummage around in my trusty spare bins I was in luck – two coil packs and some brand new plug leads.

A tiny imperfection in a coil pack insulator boot caused the world’s most violent misfire and High Tension voltage to arc all over the place.

Within two shakes of Stella, the workshop cat’s tail, the parts were fitted, fault codes erased and a damn good road thrash confirmed all was back to normal but oddly with a whole lot more throttle pick up from low revs. Equally odd was the ‘phone call from my trusty MoT tester later that day asking if he could use my car as a Guinea Pig.

My MoT chap had just taken on a new mechanic who was ex-MGR Dealer trained and he wanted to learn how to use T4 but had no MGR product booked in to have a play on. I agreed and popped by his premises that very afternoon so the pair of them could poke and prod a lap top with my car sitting there connected up to a very long and industrious looking wiring harness.

Half an hour later Rover was released back into the wild and, placebo-effect or not, the car was transformed in every manner. The slightly hunting K-Series idle was replaced with a dead level 800rpm tick over. The throttle response from idle is now almost like a two stroke racing bike (minus the blue smoke) in comparison to how it was before and little more eager through the gears – I was so pleased I could have kissed the pair of them.

I used the car for work for a couple of days and the adaptive learning MEMS3 ECU became accustomed to my driving style, making a good car even better on bitter cold mornings thanks to an engine renowned for its rapid warm up period and the 75’s superb climate control – Oh, life once again seems so good.

New coil packs and some brand new leads along with a replacement O2 sensor and a T4 ECU re-map session brought never before seen improvements – My ecstasy was somewhat short lived!

Erm… well ,it did until this morning that is. On my to work at 5.00am on the coldest morning so far, I visited my local Tesco for a paper en route and passing our local commuter station I traversed the level crossing but,as the back wheels bump-thumped over the rails, the power just died almost like the ignition was turned off – which it wasn’t.

Thankfully the road from there has a gentle downhill gradient and I could do nothing but coast to a standstill by the kerb in total darkness with an outside temperature of a brass Monkey-worrying -5 degrees. ‘Er indoors was nonplussed with me ‘phoning for a lift home, but she came up trumps with the Golf looming out of the darkness like a kind of automotive St. Bernard (minus the brandy!).

I popped back home for a torch and some spares then returned to the stricken Rover a little while later. A quick look around revealed a faulty relay in the under-bonnet fusebox. The dud relay was duly thrown over a garden wall in the traditional manner and a suitable spare replacement popped into the fuse box – et voilà, the car burst into life once again. So there we have it folks, they say trouble comes in threes and that’s my three troubles.

From now on I’m looking forward to solid reliability and an unblemished copy book – though, I won’t hold my breath just yet.

Mike Humble


  1. My sympathy goes out to you Mike… Sometimes I start work at 5.30am and the thought of “early morning car trouble” fills me with trepidation. Luckily you have the skills to get yourself going again – well done. My car is kept in a garage overnight so at least it’s frost free and slightly warmer first thing.

  2. Not opening the bonnet leads to all sorts of troubles. I recall a Marina 1.3 with the air filter cover and element down by the chassis rail – fortunately, the wing nut was still on the car, so the whole lot could be quickly screwed back together.
    Less fortunate was a big-haired lady of a certain age whom I knew in Wales. Her white 2.0 Capri Ghia Mk.3 was leaking coolant. She’d neglected it so long that the radiator bolts had loosened, and the rad had moved backwards into the fan!
    A third story seems appropriate. When I bought my 218SLD turbo, I made a list of jobs, including “change gearbox” and “repair driver’s window which falls into door”. After these major jobs, I looked at the exhaust mounts to see why the whole system was rattling. Couldn’t see a problem, so I moved down the list to do an oil change – whereupon the exhaust rattle went away. I wonder how long he hadn’t changed the oil for? He hadn’t changed the cam belt either…

  3. I also set off to work at 5am. The thought of my car breaking down in this weather at stupid o’clock does make me think. Especially when you add an MGF into the equation 🙂
    I do wonder if commuting via train would be the better option at this time of year..

  4. If that was my car, it would have gone The Journey quite a while ago. I simply won’t tolerate such unreliability.

    Incidently when I worked shifts, a day shift was a 5am start and I used my MGF. Faultless.

  5. The K’s with coil packs are prone for this,anyone had early non powertrain K series with the diode go in the rotor arm?
    (incidently ARG/Rover K’s have marked differences to powertrain K’s)

  6. i worked with a Asian lady whom brought a new Honda and drove the thing for 4 years until it stopped… she screamed at the dealer (who she hadent see for 48 months) about the broken motor… the Honda had never even seen a oil change… the black goo that was formally oil and the burnt plugs were sent to Honda for referance.

    The Accord was scrapped as completely shagged!

  7. Deffo Francis

    The rotor arm was uber common to fail on earlier K plants

    Before Unifarce went all cheap, their pattern fit ones were known for being a fault free replacement.

    Re: coils… the fault on mine stemmed from the rubber boot that slides onto the plug, but I changed both packs to be ultra sure and matching pair.

  8. I had a friend bought a cheap Ford Escort once, he never serviced it.
    One day it broke down. He got the AA out. The AA man was amazed as he pulled out the remains of half a sooty oily spark plug.

  9. Another reason why, much as I like the place I don’t live on the mainland. Getting up at 5 (or before it) to drive to work is just no good to me.

    Today I am working 16 miles away from home and the journey 9in morning traffic) took 18 minutes 🙂

  10. My zt 120 had slight missfire the other day which i put down to plugs(they were ten years old).On stripping i found it was charred black round the outside of the plug where it had been arcing past.The plugs locked in good knick but i changed them and fitted a lead that i had spare.Now runs perfect.It has to be Known that these cars have two coils and the voltage goes through two spark plugs doubling the voltage to about 40000 volts,so it does put a strain on the system.Also if you get a missfire unburnt fuel will give a wrong reading to both oxygen sensors.A bad missfire will be picked up by the ecu and the faulty cylinder will have its injector turned off,thus saving the cat.

  11. Not servicing a car is the kiss of death for it. I had a Rover 213 which had a service history and so worked faultlessly in the 12 months I had it, but severe rust meant it had to go, so I bought a Toyota Corolla next, thinking it would be just as reliable. Apart from surface rust, common on 12 year old cars in the mid nineties, it looked OK, but was a reliability disaster as it hadn’t been serviced for years, eventually running on two cylinders with oil consumption down to 250 miles for five litres, and ended up being sold for scrap as it was so shagged. ( Even a service from a mechanic friend couldn’t save it)
    However, working on very low wages and only bangers being within my price rangs at the time, I had to take what I could. E

  12. @10,the oxygen sensor will detect the misfire due to oxygen entry via shutdown cylinder it wil then try short term fuel trim to counteract this but in seconds it will have detected this well before EML comes on as a maturing (pending code).The coil packs are “wasted” spark i,e 1+4 and 2+3 spark at the same time,it would give you a good kick,SAABS trionic will kill you instantly-runs two minutes after shutdown to clean plugs!

  13. Mike, your 75 is blessed – with your dedication & expertise anyway!

    Now wishing you a long period ahead of uneventful wafting along, 75 style!

  14. i have had the same problem car cut out and will not start.engine turns over but there no fuel and no spark.do you no which relay was faulty.thanks in advance steve

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