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Premium Member
2,432 Posts
Discussion Starter #1 (Edited)
Seeing as the same questions pop up all the time I decided to start this as an easy reference for diesel owners. I'll add to it as and when I have time (I know theres a lot to get in but this is at least a start) but in the meantime anyone with decent info feel free to post and I'll add it in.

The focus of this topic is specific info regarding the engine and auxilliary systems, frequent problems and fixes. For general questions see the 7th Gen FAQ.


What's my body code?

The following body codes apply regardless of trim level:

3 Door - EP4
5 Door - EU9

What's my service schedule?

Should be completed whichever instance (distance / time) comes first.

9k / 12 months - Replace engine oil & filter, replace pollen filters, drain fuel filter pot
18k / 24 months - Replace fuel filter, inspect & adjust aux belt
27k / 36 months - Replace brake fluid, replace air filter*
45k / 60 months - Replace engine coolant
54k / 72 months - Inspect valve clearances
72k / 96 months - Replace transmission fluid (MT)
90k / 120 months - Replace timing & aux belts, inspect water pump

*The air filter does have a tendency to clog up rather quickly which has a great effect on performance so personally I'd advise doing it at 18k intervals or 9k if you can afford it.



Stands for diesel particulate filter, our model does NOT have one.


Bosch 0281

Found across a range of vehicles, see here.


Stands for exhaust gas recirculation. The theory behind this is that reburning a proportion of the exhaust gas under certain conditions (load, rpm, engine temp) NO2 emmisions are reduced. Unforunately this only works best when the engine is brand new and becomes less effective throughout it's life as sludge deposits build up inside the system and around the EGR valve. These deposits are made up of a mixture of carbon from the combustion process and vapour from the crankcase (which is vented into the intake system) and if left unchecked can cause no end of problems either at the EGR or, when carried over, on the turbocharger inlet vanes.

The easiest method of getting around this is simply to remove the system from the equation altogether either by removing it entirely or more commonly inserting a blanking plate at the exhaust end of the EGR or removing the vacuum line to the actuator. This will prevent any further deposits from accumulating inside the system but will cause the MIL to light whenever the engine notices that the EGR isn't functioning correctly (via the MAP sensor or actuator sensor). The engine will also run lean during these periods due to the higher than expected O2 content which in theory could cause damage but in reality is probably negligible. The EGR function can be removed at a software level by any decent remapper which will then prevent any of the problems associated with removal from occurring.


Isuzu 4EE2 CDTi - 101hp, 220Nm, DOHC

This engine is a modified version of the Isuzu 4EE1 and is part of the Circle L family of engines. The 4EE2 was originally produced as a Di or DTi unit for Vauxhall/ Opel and was eventually modified to a common rail unit first used in the Honda Civic and later in the Vauxhall Corsa B (not to be confused with Isuzu Z series units!).

Parts can be ordered from Honda, Vauxhall and I dare say Isuzu however there seems to be little difference in price if any so I'd just save the hassle and stick to official channels.

UPDATE 18/02/13

Several parts for the engine have been discontinued, there is still stock in the warehouse but I don't know how much. If you expect something is going to be a problem (like a rusty sump as I just found out the hard way) then I suggest you begin making enquiries as soon as you can. I don't know if it's the same story with Vauxhall but I'd appreciate it if someone in the know could clear that up.


The intercooler cools the air compressed by the turbocharger, due to the increase in pressure the temperature also rises and the air becomes less dense as a result. The intercooler lowers the temperature and in turn increases the density of the charged air. All models come with a side mount intercooler as standard.

MAF Sensor

Mass air flow sensor, located just after your air filter this calculates the mass of air entering the intake system based on flow.


This is the fuelling profile given to your engine according to the rev output. In a turbo diesel such as ours the power and torque outputs are dependant on the fuel supplied to the engine (rather than a petrol engine where the air determines the power). Air can be partially controlled by manipulation of the turbocharger at low revs but once it is fully operating control is wholly down to to the fuel injected. From the factory you usually find a car will have rather a consevative map in order to take into account massive variables such as the operating environment (northern Sweden or southern Spain?), the driver (yer Granny or the Stig?) and the likelihood of regular maintenance carried out. This is why there are such enormous gains (~30% hp) to be had with a simple "remap" as the engine can be tuned to its full potential at the cost of less reliability (if no regular maintenance is carried out or standard components, usually clutches, are overstretched) and potentially less forgiveness when being driven. Fuel economy is also usually improved as low end torque improves leading to less agressive driving being necessary (though with improved performance that call's up to you )

MAP Sensor

Mass air pressure sensor, located at the intake manifold this calculates the mass of air entering the system based on pressure. This sensor is also responsible for monitoring EGR and turbocharger function.


Malfunction indicator light.


Garrett GT1749V

This is a variable vane turbocharger from the Garrett GT family and variants of the 1749V are found in a wide variety of turbo diesels, usually around the 1.8l-2.0l range. It is vacuum actuated and apparantly good for about 220hp depending on the map applied.

There are four versions of this model suited to the Civic released in the following order:

721875-0001 (2001)
721875-0004 (2003)
721875-0005 (2004)
721875-5005S (????)

The 5005S is a direct replacement for all versions, I'm unsure what's different but I'll do my best to find out.

There are issues with the turbocharger which can be fixed under a limited time/milage warranty but if you are outside of this warranty period the good news is that a replacement from Honda will only cost £280ish which is about a third of the price other sources charge!

If sourcing a whole unit to replace yours with it MUST carry the part number 721875 in order to fit, these units are specific to the Honda Civic only and are not found in any other car. However, if you are mechanically minded then I dare say you could source another GT1749V variant and swap the housings and actuator but this needs to be confirmed. For a full list of suitable donor vehicles see here

Garrett part numbers:

215101 - gasket kit
210697 - gas entry gasket
210311 - gas exit gasket
210243 - oil exit gasket

Tuning Options

At this point a lot of people new to diesels will be wondering where you go with tuning. Actually there are several straightforward and relatively cheap ways to boost the performance of a turbo diesel and the best bit is the most expensive bits come with the car!

Air FIlter

Contrary to popular belief not actually much of a performance enhancer, more of an economy benefit really if you look at the long term cost of paper filters or convenience if you have to remove your standard airbox for any reason. Open cone filters are also an excellent way of pumping all that lovely hot air in your engine bay straight into your engine, yummy.

Cold Air Feed

Dump Valve

Just . No benefit whatsoever. The theory is that is prevents throttle damage by turbo surging during gear changes however due to the fact that diesels don't have throttles - they're useless. Probably increases spool time as well due to system pressure loss.

ECU Remap

By far the most effective and cheapest method (per hp) of unleashing more power and, believe it or not, better economy from your engine. This involves adjusting the fuelling and boost settings in order to optimise the performance of the engine, if you're only going to do one thing to your car this is it. Typical figures quoted are around 30% gains with no other work, you will pay £300 - £500 for this service and other jobs like getting the EGR mapped out can be completed at the same time. If you choose a remap then make sure it is from a reputable tuner and that it is dyno proven (on a reliable dyno!) with before and after runs at a minimum.

The lower end of the price scale will tend to involve your cars standard map being downloaded, tweaked for better performance (either in the premises or at another site) and then uploaded back into the ECU. The more expensive options will involve a 'live map' which involves hooking your car up to a computer, putting it on a dyno and adjusting the map in real time. Whilst this is more expensive it gives a far better result in the end and should be less likely to result in remedial work. If you are planning on any other performance upgrades then a remap should be the last job on the list in order to get the full benefit of your labours.


Besides a de-cat freeing up a couple of horses the performance gains are minimal. A decent full stainless system will however look pretty and should last forever. Normally a full straight through system with no boxes should be fine in terms of noise legality but don't blame me if it sounds like a tractor!




Most diesel tuners will upgrade the standard cooler which may be side mount or an intracooler (top mount) or if you are fortunate, front mount. The usual choice for an upgrade is an FMIC (Front Mount InterCooler) either custom or taken from a turbocharged model in the same car family for convenience. Either way brackets will require installing and some modification work will be required to make it fit.


Propane/LPG Injection

Snake Oil

Fuel magnets, hydrogen generators, electric turbochargers, vortexes, anything else found on eBay for under £20. Repeatedly proven not to work and ususally hindering performance (thorough "research" courtesy of our american cousins, of course).

Tuning Box


Water/Methanol Injection

Performance benefits are debatable and conclusive testing remains to be seen however water injection will prevent the formation of NOX as combustion temperatures are lowered with no performance penalty.

Premium Member
2,534 Posts
do you know anything about the 2.2 CDTI engines mate? looking at getting a type S GT or sport both 140bhp engines. Any knowledge you can share is appreciated.
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