Technician’s Update : For the best answer, speak to ERIC

The styling was pretty much finalised in the 1970s but, despite its looks, a post-1989 petrol Montego is pretty hi-tech

Earlier Montegos… you can shove ’em. When I say earlier, I mean anything prior to the 1989 model year. Once the revised cars came along, the Montego became a dependable car thanks to a decent gearbox (on the 1.6) and, more importantly. superior electronics overseeing matters under the bonnet. Prior to this, they were pretty dire in terms of reliability – it’s just a shame it was left so late to be addressed. Don’t shoot me down in the comment box below, deep down in your hearts, you know I’m right.

The 1.6-litre S-Series engine is rather like the K-Series, insofar as that, even today, it’s a very misunderstood engine. Okay, so it never won awards for its smoothness – a Blackpool hen party is more refined. Once Rover had seen fit to throw away the Volkswagen-sourced gearbox and fit the T5/PG1 transmission, it gave a pretty good account for itself. In terms of economy, torque and motorway cruising the S-Series, in my humble opinion, was light years ahead of the 1600cc ‘Pinto’ you found in the Ford Sierra at that time.

No longer would the automatic choke kick in accompanied with a flashing red overheating LED on the temperature gauge when driving down the motorway in deep winter. No more would the engine hunt for an idle speed as if it was running out of petrol. This was all due to the riddance of the terrible Lucas programmed ignition system with its countless operating modules replaced by a thoroughly well-developed single ECU process called ERIC (Electronically Regulated Ignition and Carburation).

Rough running on a petrol Montego of this vintage nearly always happens as a result of something life-expired.

Anyway, I recently spoke on the ‘phone to an old work chum who sticks his toe in the retro car scene now and again. Normally, he’s a total sucker for a Vauxhall Cavalier, but this time he’s moved away from Luton and headed for Cowley after picking up a J-plate 1600LX Montego. However, as according to my friend, it’s not been without trauma as he discovered that the car wasn’t running particularly well. Rough running on a petrol Montego of this vintage nearly always happens as a result of something life-expired.

What’s not needed to get an S-Series running right

After changing the plugs, leads, rotor arm and cap, he mentioned it still felt sluggish and a bit hesitant under part throttle. Now, my money is riding on a gummed-up carb and/or perhaps a carbon build up in the combustion chamber – I’ve seen it a hundred times or more. Being a have-a-go hero and no more, he knows his limitations and so he entrusted a well-known chain of garages to look into the poor running so long as it wasn’t going to break the bank.

Trying to adjust or fettle the carburetor on these later engines is pointless without the correct kit. Even then you really have to know exactly what you’re doing. The ERIC ECU can be seen behind the battery on this 1990 1600 LX Montego

He’d done his research and knew all about the engine management system, and before handing the keys over he asked if they had the tools to diagnose any error codes. Satisfied with their answer, the car was left with them for a couple of hours. However, on collecting the car he was alarmed to notice no difference – more to point, it ran even worse than before. Aggrieved at parting with £90 for an almost undrivable car in return he went to the garage for a word or two.

Unless you have COBEST, Microcheck or other specialist Rover tools, meddling with the carb on an ERIC-equipped Montego is about as effective as playing an LP under water.

Among the troubles, was a too-fast idle speed that caused the engine to run on after switching off (a common trait) and even more hesitancy when trying to maintain a cruising speed on a part-throttle. All the garage had done was wind up the idle speed and lean off the mixture. Unless you have COBEST, Microcheck or other specialist Rover tools, meddling with the carb on an ERIC-equipped Montego is about as effective as playing an LP underwater.

What is needed to get an S-Series running right!

Thankfully, after a heated conversation, the garage manager was summoned and his money was refunded, but he’s still left with a poor-running Montego. All is not lost, as I’ve put him in touch with a garage that used to be a retail Rover dealer in the south Midlands, which I know still has the required equipment to tune the engine quickly and correctly. Once in a blue moon this kit pops up on eBay and, if the price is right, it’s worth investing in.

But it doesn’t stop with Montego or Maestro. Pre-OBD-equipped Rovers rely on software such as Microcheck right up to 1999. Owing to the sharp decline of these cars on the roads nowadays most garages simply throw this equipment away.

Older Ford and Vauxhall drivers also suffer the same problems when it comes to software interrogation so it’s not purely just Rovers. The best advice I can give is check out the owners’ clubs – there’s always a helpful member who has a box of electronic magic tricks.


We have spoken again this evening and it turns out he’s sorted the car out. The mixture was over-lean, the idle speed was too high and there was no oil in the carburetor dash pot either. The garage attended to the aforementioned, sold him a bottle of nuclear-strength fuel treatment, and instructed him to, ‘give it a good hiding’. This has been duly adhered to and my pal, Chris, reports that it’s running fine.

Top marks go to P.J Green & Co of Flore in Northamptonshire – a former Rover dealer of high repute!

Mike Humble


  1. OK… I’ll be first to comment.

    To use some of your words, deep down in my heart I know from real user and ownership experience you are wrong! Having used, owned, and still own Montegos over the whole range of changes from day one of production until the last one rolled off the production line. New and used. So there. Hugely underestimated car from all aspects particularly within Motoring Media circles. That media negativity became “gospel” within car consumer circles.

    Worth repeating… so there … 🙂

    • There’s more. Auto-choke issues were often “cured” by a simple Manual Choke conversion. However, this did NOT cure the original problem only dodged round it. More often than not, the real cure was a simple DIY fix. Fit new O-Ring Seals in the Auto-Choke as the originals like most things, would lose efficiency with age and exposure to many hot-cold heat cycles in the hostile engine compartment environment. Our G-Reg 1.6LX was my other half’s daily driver for thirteen years from 1990 until 2003. Still running strong when I drove it to the local breaker yard after taking delivery of the new ZS in 2003. Extremely reliable was that 1.6LX when it was replaced by an equally reliable new “They all do that” 1.8 MG ZS which she uses as her daily driver to this day. This one has not done that either … yes but, we keep an eye on things as all car users should be duty bound to do if only for safety reasons. Reading of those seals perishing in the 1.6 S-Series Auto-Choke back then, I bought a couple of sets of them ( about two quid ) in readiness should our 1.6LX “do that”. It never did and I still have those seals unused in my box of spares.

      By the way, I was stopped by the boys in blue on the M42 for pressing on doing a three figure speed in that 1.6LX. “No way would this old Montego do that kind of speed Officer” I was very tempted to say… but, did not … :-). Trying to start the 1.6LX on the hard shoulder after that stoppage was the first and only time the car suffered heat soak fuel vaporisation. Eventually when cool fuel reached that carb it spluttered into life and ran like its usual smooth self soon after. Hot run immediate engine switch off can cause problems that’s why folks are advised to idle their cars, particularly Turbocharged ones to allow for heat issues like that before switching off. I have done so ever since.

      Whilst many of those “In the Trade” know lots about lots of cars, none ever know everything needed to know about any one car. That 1.6 S-Series probably qualifies for that accolade for numerous reasons. Ours was a superbly reliable and economical unit. Quite nippy too … ask the BiBs… 🙂

      Lost count of the times folks have asked me “John you know about cars, my …” when they have spent much of their hard to come by with pro-outfits and still the car has problems. I am not exaggerating in saying I’ve lost count of those times. Over the past dozen or so years I have bought eight MGs and Rovers where the frustrated owners have been professionally advised their poor car has the “They all do that” so called head gasket failure. I paid a price to allow for such remedial work. None of those MGs and Rovers had a damaged Cylinder Head Gasket .. their engines included near bullet proof T and O series as well as the K-Series. Coolant losses and resultant overheating due to other causes ranging from worn out Water Pump to a small unseen split in a coolant hose. Very convenient get out to blame the car on a “They all do that mate” basis.

      Two of those eight “They all do that” cars were bought from car dealers who also had been given wrong diagnosis. Traders know how to trade but, often clueless about what goes on under the cars bonnets.

      Funny old game folks and cars.

  2. It’s getting increasingly difficult to find the tools required to support a lot of early ECU controlled cars. I was fortunate enough to find the man with the only working equipment in the UK to speak to the Zytek ECU on my 1992 XJR-S, but that equipment isn’t going to work forever. Even finding a hydrogas fluid pump is an effort now!

  3. Another interesting anecdote.

    Which fuel treatments do you recommend for petrols and diesels – there are many brands but some are just expensive snake oil and do nothing?

    • Liqui-Moly Proline jet clean worked for the injectors on my diesel X type. I have a picture of the can, but inserting a picture into this comments box is completely beyond me.

  4. My old Employers had two Montego estates (a 1985 1.6 base then a 1989 1.6LX). The latter car was much better than the first – in equipment levels, performance and reliability. So much so, my colleague purchased it when he retired and ran it for a few more years.

    It was the same metallic blue as shown above.

    • The facelifted F reg onwards cars seemed to be vastly better built than the original Montego. I had one that was made just before the 1988 facelift and the quality and reliability were terrible, whereas a work colleague with a facelifted car had very few problems. It’s a shame really as the Montego was always a good car to drive with plenty of space and comfortable seats.

  5. This takes me back to my days on maintenance in QT (where the Montegos were assembled). When ERIC was introduced there was a Carburetor with little arms, legs and eyes used by the service team. The literature with him said “Hello, I’m Eric and I stand for…..”
    The new ECU was set at an angle so that rain water ran away from the electrical plug, one of the causes of ECU failure on the pre 89my cars.
    Noticed a tidy M reg Countryman today, Nightfire Red, looked quite small against the modern stuff.

  6. Resoldering the Eric box usually cured most related faults. The S series was a good engine in my opinion. I had mine for 160,000 miles. I didn’t consider it especially unrefined.

  7. My experience fits in with the article as we started with a two tone saloon in 1988 that had the original electronic choke. I sold it at 50000 miles and was contacted by the purchasing garage to ask if I had had any problems with the choke (which I had not) It literally died the week after I sold it . The car was replaced with an H reg facelift which was a nice car and I challenged the kids to find the 20 or so differences from the ’88 model. This car only lasted 18 months or so as we bought a dog that needed an estate and the J reg 1600 estate (with optional power steering ) lasted with us until 1999 and the mileage was 110,000 with no mechanical problems at all. The car only lasted a short time after that as the flloor was close to parting company with the rest of the car. So basically we survived the 1990s with some nice comfy reliable transport.

  8. I had 5 Montego 1.6’s in succession, running each for about a year and doing about 25,000 miles.The first was late ’85, the last, a facelift 89 F reg. I agree with Mike (partly), that the Facelift car is hugely better. Great gearbox (unlike the VW sourced box), excellent seats, well equipped and not a lot to criticise. A friend took a 1995 Diesel Countryman to 200,000 in four years without much grief.

    I would say of the earlier cars that each one was just a bit better than the one before. In 100,000 miles I only had one breakdown – just a simple flooding of the carb on a quick restart after half a mile from cold. Lots of issues with trim fit, but I was pretty fussy. Performance did vary though, even though supposedly identical. My 86, first of the two-tones was my favourite. It could wind up to 126mph on the clock (downhill, wind behind, of course), and left my pals 1.6 Orion for dead from the lights. I also thought the S series worked far better in the Monty than in the 216S.

    They certainly got my vote above the Cav and the Sierra.

    • It’s a shame it took 5 years for the Montego to come good, but once a turbodiesel was launched, you had a very capable and economical car that was generally reliable. Also a two litre petrol estate in British racing green was a nice car.
      Speaking of British family cars of this era, don’t forget Nissan were churning out tens of thousands of Bluebirds in Sunderland with the same level of reliability as their Japanese cars and Peugeot had the highly capable 405 coming out of Coventry. As for the Sierra, by the late eighties this had become even more dated than the Montego due to rwd and was developing a reputation for unreliability.

      • Nissan Sunderland went on to assemble the Nissan Almera and K11 Micra cars, both cars were top of the charts for reliability and few warranty claims.
        Nissan Sunderland had the highest productivity levels in Europe too,each year 100 cars per employee. more than 250% of the productivity of mainstream European car plants.
        No surprise the French protested to the EEC when the Japanese approached the UK to set up car assembly here.

  9. I was one of the ERIC software team back in 1987/88 and I’m really pleased to hear that our efforts made a noticeable difference. We were a small team based at Ashold Farm, part of the Power Unit Systems group. I am proud of having worked on both ERIC and MEMS software in the early stages of my career, two systems that, in my opinion, were far superior to the Lucas alternatives. While I only spent a few years working directly on these systems, the experience I gained was a positive influence on my subsequent engineering career.

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