BMW 1 Series 116i to M140i · E87 & F20 Generations

The E87 116i arrived in New Zealand as BMW's entry level compact hatchback, and for a lot of buyers it was their first taste of rear wheel drive in a car this size. Under the bonnet sat the N45B16, a naturally aspirated 1.6 litre four cylinder producing 122 hp and 160 Nm. No turbo, no drama at low revs, just a clean, revvy engine in a well sorted chassis. These cars were genuinely fun when new, and a surprising number of them are still doing daily duty around Auckland.

The catch is that the E87 is old now. Deferred maintenance that was easy to overlook five years ago is becoming serious money today.

The N45B16 is a naturally aspirated engine without the turbo complexity of every generation that followed, which makes it simpler in some ways but it still needs the right attention. The ECU options across the E87 run include Bosch MEV17.4.6, Siemens/Continental MSD80 and MSD81 depending on build date and market. That mix matters when you are coding replacement parts, which is exactly why generic scan tools fall short on these cars. We use factory BMW ISTA diagnostics with a genuine ICOM interface on every E87 that comes in.

Routine servicing on the N45B16 means the correct BMW Longlife 5W-30 grade oil, not whatever is on special at the auto shop, plus air filter, cabin filter, drive belts, correct spark plugs and ignition coils, and brake pads and rotors. If the timing chain has not been done and the car has got the kilometres on it, that conversation needs to happen before something lets go.

The E87 116i is the foundation of the whole 1 Series story. Get one that has been looked after and you have got a genuinely rewarding driver's car. Get one that has not and it will teach you expensive lessons quickly.

When BMW updated the 1 Series into the F20 body and then refreshed it with the LCI, the entry level 116i made a significant jump. Out went the naturally aspirated four cylinder and in came the B38A15M0, a 1499 cc three cylinder turbocharged petrol. On paper that sounds like a step backwards. In practice it is a clever, torque rich engine that pulls well from low revs and delivers better real world economy than the old N45. The stock figures are 109 hp and 180 Nm, less peak power than the E87 it replaced but with a broader, more usable torque spread.

The B38 architecture is shared with the MINI and later BMW small car platforms, and it is a genuinely modern piece of engineering. The Bosch MEVD17.2.3 ECU controls it with a high level of sophistication. But that three cylinder layout and the direct injection setup bring their own set of specific weak points.

Compared to the E87 116i, the F20 is considerably more complex to work on correctly. The MEVD17.2.3 ECU controls start/stop, boost management and a raft of driver assistance functions, and replacement parts need to be coded to the car properly. That is not a job for a generic scan tool. We run factory BMW ISTA with an ICOM NEXT interface on every F20, which means we read actual live data, not just fault codes, and we code every replaced part correctly first time.

If the F20 116i is the entry point, the 120i is where the F20 platform really starts to sing. The B48B20B is a 1998 cc four cylinder turbocharged petrol with an 11.0:1 compression ratio, 184 hp and 290 Nm from the factory. It shares the same 82.0 x 94.6 mm bore and stroke as the B38 in the 116i, but the extra cylinder and displacement make a real difference to how the car pulls through the rev range and feels on a mixed Auckland commute that opens up on the motorway.

The B48 is generally a solid engine. It is newer tech than the old N series motors and BMW learned from many of those lessons. But it is not without its issues, particularly as mileage builds.

The ECU setup on the 120i F20 is a Bosch MG1CS003 or Bosch MED17 paired with the ZF 8HP automatic gearbox controller where fitted. Both need factory level coding for correct operation, which is exactly what we deliver with BMW ISTA running through a genuine ICOM NEXT interface. If your 120i is throwing vague faults or a workshop could not tell you what module was actually at fault, bring it to us.

The 123d is the outlier in this family, and that is exactly what makes it interesting. While every other variant here runs petrol, the E87 123d dropped the M47TU2D20 twin turbo 2.0 litre diesel into the 1 Series shell and produced 204 hp and 400 Nm. In a car this size and weight, that torque figure is transformative. It is also the most complex engine in the E87 range by some margin, and it is the one that punishes a lack of knowledge the hardest.

The M47TU2D20 uses a sequential twin turbo setup where a smaller turbo handles low end boost before the larger unit takes over. That sequence is clever but the smaller turbo is a known weak point over time and mileage. Beyond that, the diesels in this era have a predictable set of problems.

The 123d runs a Bosch EDC17CP02 ECU, which is a diesel specific platform and not something you want a generic tool prodding around in. We use factory BMW ISTA with a genuine ICOM or ICOM NEXT interface, so fault reading, DPF and EGR diagnostics, and any replacement part coding is done correctly. For DPF and EGR concerns we diagnose and clean or replace as required. Where forced regeneration is needed we run it on factory software, not guesswork.

Glow plugs are part of routine servicing on this engine, along with the correct BMW LL-04 grade oil, fuel filter, air filter, cabin filter and drive belts. Brake pads and rotors, suspension, clutch and gearbox work all come under what we cover on the 123d.

Compared to the petrol 116i E87, the 123d is a completely different proposition. Same body, similar chassis, but the engine and its requirements are worlds apart. Do not let anyone service it with a petrol mindset.

Here is where the 1 Series story takes a sharp turn upward. The E87 135i with the N54B30 is a completely different car from anything else in the E87 family. A 2979 cc twin turbo inline six, 84.0 mm bore, 89.6 mm stroke, 10.2:1 compression, and 306 hp with 400 Nm of torque. Same body as the 116i, but an entirely different mechanical reality. It is one of the most rewarding performance cars BMW built in this era, and it found its way into the New Zealand fleet in meaningful numbers.

The N54B30 is a strong engine but it has a set of well documented weak points that every owner should know about.

The ECU on the N54 E87 is Bosch MEVD17.2, Siemens/Continental MSD80 or MSD81 depending on build. The N54 also uses direct injection, so carbon build up on the intake valves is a real concern at higher mileage. Walnut blasting is the correct fix. We have done plenty of them.

We diagnose these with factory BMW ISTA using a genuine ICOM or ICOM NEXT interface, which means we can see the real live data from both turbos, both banks of injectors and the HPFP, not just a fault code list. Routine servicing includes the correct BMW Longlife 5W-30 oil, air and cabin filters, drive belt, and six fresh spark plugs and coils because the N54 is genuinely sensitive to worn ignition components under boost.

When the 1 Series moved to the F20 body, the 135i made the jump with it and swapped the N54's twin turbo setup for the N55B30, a single twin scroll turbo straight six with the same 2979 cc displacement, same bore and stroke, but refined internals and a cleaner forced induction architecture. Stock output went up to 326 hp and 450 Nm. BMW's intention was a simpler, more refined system, and in many ways the N55 delivered. But simpler does not mean trouble free.

The N55 addressed some of the N54's worst habits. The HPFP drama is largely gone, and the injector issues are much less common. But the F20 135i brought its own set of things to watch.

The F20 135i runs Bosch MEVD17.2 or MEVD17.2.6 depending on build date. Parts coding and module adaptations need factory software, which is exactly what we use. ISTA running through an ICOM or ICOM NEXT gives us live data from the entire drivetrain, not just the fault code register.

Compared to the N54 E87 135i, the N55 F20 is a more refined daily drive but gives up a little of that raw character. Routine servicing covers BMW LL-01 grade oil, air and cabin filters, spark plugs and ignition coils, brake pads and rotors, drive belts and the cooling system including a proactive water pump replacement.

The M140i is the car the entire F20 performance range was building towards. BMW fitted the B58B30M0 into the F20 shell and gave it 340 hp and 500 Nm from its 2979 cc single turbo straight six, an 11.0:1 compression ratio and Bosch MG1CS003 ECU management. On the outside it looks like a slightly aggressive hatchback. In traffic it behaves like one. Push it and it is a different story entirely.

The B58 is generally regarded as BMW's most robust modern six cylinder. It learned from the N54 and N55 before it, and the fundamental architecture is stronger. But do not mistake robust for maintenance free.

The MG1CS003 ECU is a sophisticated modern BMW platform and it needs factory tooling to work with correctly. We run ISTA through an ICOM NEXT interface on every M140i that comes in, which means proper fault reading, correct adaptations after any repair, and coding that actually sticks.

Routine servicing covers the correct BMW Longlife spec grade oil, air filter, cabin filter, wipers, spark plugs and coil packs, and brake pads and rotors given how these cars actually get used. Proactive water pump and thermostat replacement before they fail is money well spent. We also cover walnut blasting the intake valves, drive belt, clutch on manual cars and suspension refresh.

The M140i sits at the top of this entire family tree. If the E87 116i started the story with 122 hp and simple naturally aspirated engineering, the M140i ends it with 340 factory horsepower and enough torque to make most sports cars nervous. Both reward attentive ownership. Both punish neglect. That has been the consistent theme across every generation on this page.