Jonty's MR2 Turbo

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Doctor doctor...

With motor vehicles it's inevitable that problems are going to occur at some point or another.  They can range from annoying niggles and very minor problems to the more frustrating and expensive ones.  What's handy though is if you can attempt to diagnose and correct the fault yourself, calling upon extra help only if you need it.

Given how long the MkII MR2 has been on the scene, lots of problems are the result of wear and tear and age.  Mix in a little premature ageing due to hard driving styles perhaps, and welcome to the world of MR2 maintenance!

There are a number of problems which are typical with a MkII MR2, of which a few have been documented below.  Added to some of my own that I've experienced, if you're suffering from the same symptoms then you have a good starting point.  The list isn't definitive but will go some way to pointing you in the right direction.

With the odd reference to my Service & Maintenance page, you might also want to have a read of that at some point.

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Engine check light

Given the amount of electronics in modern day cars, it's no surprise that an on-board diagnostics system needs to exist so that problem situations can be logged, reported, and remedied.  Controlled by the ECU, if an error condition occurs the engine check light on the dashboard will illuminate for as long as the problem exists.  If it stays lit then you've got a permanent problem but even if the check light goes out it doesn't mean the fault won't reoccur, so it pays to find out what happened so you can take corrective action.

To check for error codes you simply need a paperclip.  In the engine bay lives the grey diagnostics port, protected by a flip-cap (see here).  With the ignition off, bridge the E1 and TE1 connections using your paperclip and then turn the ignition on (but don't start the engine).  Spy the dashboard and the engine check light.

Steady and constant flashing means all is okay.  If there's any pattern or sequence of flashes then the ECU is reporting errors -- past and/or present.  Flashing sequences are codes which will need to be cross-referenced.  Here's a useful website where you can do this:

MAD Mechanic

Click on Links / Make & Model / Toyota / MR2 OBD codes

Here's how to understand the check light's pattern of flashes, using an example.  The error code 34 (boost pressure problem) will cause the engine check light to flash 3 times, pause, flash 4 times, pause, and then either repeat or display another code.  At the end of the complete sequence all codes will be repeated.

To clear problem codes (either once the problem has been cured or to see if it's just a one-off), the ECU needs to be reset.  Disconnecting the battery will do this but you'll also lose clock and radio settings.  Instead, consider resetting the ECU -- details of which you can see here.

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Aerial fails to go up or down

If you suddenly find that your aerial mast refuses to go up or down, the usual suspect is the toothed nylon cord which resides inside the mast itself.  Simply due to wear and tear, it's prone to snapping or if it gets jammed then some of the teeth may sheer off.  This is easily fixed by obtaining a replacement mast but before doing so it's wise to check that you can hear the motor whirring when you turn your head-unit on/off.  If you can't then the fault may lie somewhere else.

Assuming the mast is at fault, order a new one direct from Toyota.  Just tell them you have a Rev1/2 with 3-piece spoiler or a Rev3+ where the mast bolts directly onto the wing.  A mast on its own should cost no more than £50 new and is much cheaper than buying an entire mast and motor package.

The task of replacing the mast can be very messy (as you have to open the gooey spool housing) but is reasonably straight forward and cost-effective.  Details on how to do this can be found here.

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Adverse tyre wear

If you find the wear rate of one or more of your tyres is extremely unusual then you should subject the car to a 4-wheel alignment or geometry check -- preferably at a motorists centre that can cater for the MR2 and its appropriate settings.  Incorrect camber, caster, and toe parameters can not only affect the handling characteristics of the MR2 but may also contribute to adverse tyre wear.

After any major suspension work or confrontations with pot-holes and the like, the geometry should be checked.  Due to the appalling state of Britain's road I have the geometry checked once a year regardless.  The settings shown above are actually for a Rev3+ but with my uprated suspension I find I get excellent handling and even tyre wear.

Correct tyre pressures are almost as important as geometry, however, without the latter being set correctly then pressures could be a lost cause.  Given that we all use differing tyre makes and models along with our own driving styles, I typically find that the ideal tyre pressure for front and rear is reliant on some trial and error (keeping a record of pressures used and how the tyres have worn over a number of months).

Further details on tyre pressures can be found here on my Service & Maintenance page.

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Reduced boost pressure

Reduced turbocharger boost pressure is quite an extensive area to cover but I'll attempt to touch upon the main areas to give you a good starting point.  Once your MR2 Turbo has reached the desired operating temperature, full boost can be achieved.  Looking at your coolant temperature gauge, if it's not at the half-way mark then don't bother trying to achieve full boost -- it's not good for your engine and the ECU may step-in and operate the T-VSV (if not disabled) to drop boost as a protective measure.  Always wait for an engine to reach normal operating temperature before driving it hard.

Being of Japanese origin, the MR2 Turbo's ECU and timing is set-up for Japanese fuel (typically rated at 98-100 octane or RON).  Using a fuel of inferior rating may lead to pre-ignition (detonation or 'knocking') when the engine is driven hard, causing long-term damage if repeated continually.  Given that UK standard unleaded petrol is rated at 95 RON and super-unleaded at 97, we have a problem... don't we..?

Shell's V-Power (petrol) is rated at 99 RON and is what all Japanese high performance engines need.  There is also Tesco's 99 Octane unleaded petrol, which is very, very good but V-Power seems to have the edge.  I'll avoid all the science but basically the higher the octane rating the more stress, heat, and punishment the petrol can take before it self-ignites.  If you abused some American unleaded (e.g. 87 RON) and V-Power or Tesco 99, the American fuel would self-ignite first.  This is what pre-ignition and knocking is all about in turbocharged engines -- use an inferior fuel (especially when running higher boost) and it'll explode before it should, causing piston damage and all sorts over a period of time.

Given the MR2's clever ECU, when it detects knocking it momentarily retards the boost by initialising the T-VSV -- a superb safety feature if not an interesting experience when suddenly the boost dies and the car feels as though it's hit a wall.  For those not using Shell's V-Power (or other high quality fuel) in their turbocharged MR2 then this really is an area you need to review.

Whether you've needed to alter your petrol strategy or not, the next step to consider is resetting the ECU.  Given that it costs nothing other than five minutes of your time, this would come highly recommended in case the ECU is simply holding back for some reason.  Checking for ECU error codes has been covered above and the reset process here on my Service & Maintenance page.

If your engine's warmed up and using a good fuel but still not managing full boost then it's time to look in the engine bay.  The nature of turbocharged engines means they're classed as forced induction (air is forced into the combustion chamber), whereas standard engines are naturally aspirated and air enters according to physics like gravity.  As to not spend hours missing the obvious, check ALL the induction pipe-work for any cracked or loose pipes (especially if you can never reach full boost).  It only takes one defective pipe (from the air filter and before or after the turbocharger) to upset the car's induction system.

How the engine fires is dependant on a number of integral ignition components, all of which need to be in good working order.  If they become worn or tired then (and more evident with a turbocharged engine) it will begin to hesitate or stumble when being subjected to full throttle.  The components in question are the spark plugs, HT leads, distributor cap, and rotor arm.  As these parts are relatively cheap to replace, it's always best to check and replace these first if no other culprits can be found -- leaving the HT leads until last as they're generally the most expensive of the bunch.

If after all the above you're still experiencing boost issues then it's time to explore the possibilities of having a defective blow-off valve (BOV), incorrect timing settings, or other, more serious problems which may call for expert attention.

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Brake warning light when accelerating

After a few months of owning my MR2 I noticed that the red brake warning indicator would light up when accelerating hard, especially from a stand-still.  This is actually due to a low-level of brake fluid in the reservoir.  Not low enough to cause problems but just enough to trigger the sensor.

This scenario typically occurs as brake pads and discs wear, causing the pistons to have to travel further and the fluid level drops as a result.  To cure the problem simply top-up with some more brake fluid.  Of course, should the warning light illuminate outside of these circumstances (and stay lit) you should stop the car immediately and investigate.

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Dim instrument panel

Some MkII models (predominantly the UK ones I think) are fitted with a rheostat which allows the driver to adjust the brightness of the instrument panel.  Unfortunately Japanese models don't come fitted with this feature and some owners (myself included) claim that the standard dial brightness is a bit dim.

Not to be out-smarted, a brighter bulb option is available from Toyota parts counters and I should imagine most auto factors too.  Rated at 3.4W compared to the standard 1.2W, a change of bulbs is an easy solution and doesn't present any issues.

Aside from this, upon inspecting the existing bulbs they may be found to have blackened over the years and therefore just need replacing anyway.

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Engine revs but little or no acceleration

When a clutch begins to show signs of wear (when it begins to slip) the symptoms can be quite noticeable.  Although meant for cruising only, a lot of motorists use fifth gear to accelerate and overtake and this is where the problem can be first apparent -- as the revs/rpm rise there is little or no increase in speed.  This may occur only once, every now and then, or simply all the time, but either way, it's indication of a worn clutch.

As a clutch continues to wear other gears like fourth and third may also be stricken with a lack of acceleration as the clutch struggles to deliver the power being generated.  Hill starts may also prove difficult (perhaps impossible), as too may driving up steep inclines, and if a horrible smell is the result after experiencing problems then a replacement clutch should be sought -- and quickly!

Ignore a failing clutch and you do so at your peril.  Not only may it be extremely embarrassing when you finally break down but constant perseverance may also cause damage to the fly-wheel (an added expense you don't need!)  Having experienced a failing clutch myself, you can see more details here on my Engine & Transmission modifications page.

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Smelly air conditioning

When in use (and especially when first switched on) air conditioning systems can generate an unusual smell which can be quite unpleasant in the more serious of cases.  This nasty fragrance isn't uncommon and is due to the presence of bacteria in and around the evaporator casing -- a simple bi-product of air-con.

To combat this problem, consider the use of cleaners which although are few in number, are available on the market if you look hard enough.  One such cleaner is documented here on my Service & Maintenance page.

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Wobbly steering wheel (warped brake discs)

An early indication that one or both of your front brake discs are becoming out of shape is a noticeable wobble of the steering wheel -- typically when cruising at speed and even more pronounced under braking.  The main culprit is excessive heat which the discs just aren't designed to handle, either because there's a fault in the braking system or the types of discs being used don't match the driving styles they have to stop.  Warped discs might occur almost instantly after a track-day or over a period of months for reasons unknown.

The wobble occurs (and usually gets worse) because the disc(s) are no longer perfectly shaped and any deformities are transferred back up through the steering mechanism.  Another symptom (which is also very good for diagnostics purposes, especially on the rear wheels) is a very warm alloy wheel.  After a reasonable drive involving fair amounts of distance and braking, pull-up and inspect each alloy by simply placing your hand on it.  If you find one is noticeably warmer than the others then this would indicate sticky brakes.  With extreme caution you could also check the temperature of the discs -- but at the risk of burning your fingers if you're not careful.

The MkII MR2 is renowned for its sticky brakes -- the pistons begin to stick, don't retract properly, and keep the pads in contact with the discs more than they should (generating excess heat).  Less likely but still feasible are the owners who install unsuitable combinations of discs and pads and/or who drive their MR2 like a Formula 1 racing car all the time.  Even in standard form the brakes on an MR2 are mind-blowing (and can catch out unsuspecting followers) but subject them to too much abuse and uprated performance parts should be considered.

To combat sticky pistons either a caliper refurbish kit can be used or a more expensive option is to purchase a reconditioned caliper.  Even more expensive is to buy a new caliper but that's just silly.  I prefer to purchase refurbish kits as they're reasonably cheap.  The only downside is the time it takes to refurbish the calipers.

A new set of discs isn't to be forgotten either -- once they're warped they can only be machined by professionals but it's not worth it in my opinion.  Once replaced, if the new ones also begin to warp then further examination may be required (or self-assessment of one's driving styles!)

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Windy wing mirrors

Whilst driving along at speed if you can hear what seems to be air entering the car near or around the wing mirrors then it probably is.  The MkII appears to have a slight design flaw in that the wing mirror assemblies let air in due to their construction and insufficient insulation.  The end result can be noisy or windy wing mirrors (or tweeter covers to be more precise).

The most time and cost-effective solution is to ensure the radio drowns out this noise but it's not really ideal or good for the ear drums.  So, consider stripping the mirror housing on the inside and blocking the holes with some suitable material.  Ben Formesyn has documented a solution for this, which can be found here.

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