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Brake Pad Shims and Copper Grease
Should brake pads have shims fitted to prevent movement/squeaking brakes? Is it advisable to use copper grease on the back of pads & on the caliper?
Shims are designed to dampen noise/vibration - some applications do use pads that have shims fitted, however some applications do not use pads with shims - it depends on the OE design. It is worth noting that most modern applications will use brake pads with shims fitted. The best thing is to check the spec of the OE pad and whether it is a design that uses shims and then replace with a part from a reputable supplier that has parts matching OE quality.
Copper grease should only be applied to the tips/parts of the pad that are in direct contact with other moving parts/sliders - it should not be applied across the whole pad or shim as this will compromise the anti-noise properties. Again, it should only be applied to moving parts on the caliper, not applied to the whole unit.
EGR Valves - Adaptation
I have recently had a problem with an EGR valve replacement job where I have replaced the EGR valve itself, however the vehicle is registering the same faults. I have checked related components such as the air mass sensor, throttle body and vacuum pump and these seem to be in decent condition and functioning correctly. Is there anything I could have missed?
When replacing electronic components such as EGR valves, air mass sensors and throttle bodies, many modern vehicles will require an 'adaptation' process to recognise and 'learn' the characteristics of the newly fitted component. If this is not done then it may appear that the new component does not work. The adaptation process can be completed by a longer test drive which allows for a full set of sensor calibrations to occur, or by using the 'default setting', 'basic setting' or 'adaptation' options on the diagnostic tool.
VW Golf Starting Issue
We have a 2004 VW Golf 1.9TDi with a BKC engine code. When the engine is hot, registering 90°C on the temperature gauge, and if you leave it for a couple of minutes, the vehicle will not start very easily - it turns over for a prolonged period of time before it eventually fires up. There are no issues from cold or when the engine has cooled down a bit. The car has been scanned for fault codes, however none were found. Any help would be greatly appreciated.
This issue could be due to a number of factors and a number of components could have an impact on the vehicle starting under these conditions. Starting with the least expensive components, we would recommend checking the following:
- Are there any air leaks from the fuel pipes? If so, replace as required
- Fuel filter - check condition and for any signs of blockage
- In-tank pump - check condition and for any signs of excessive wear
- Injectors - check for correct functioning of the injectors on a test rig for correct flow rates and injector wave forms
Any damaged, worn or incorrectly functioning components should be replaced as required.
Audi A2 Misfiring
I am working on an Audi A2 which is misfiring and has a lack of power, what could be the cause?
Assuming the Audi A2 is a petrol version, misfires and lack of power could be a symptom of a fault with the ignition system. Depending on the year and model this could be either a direct ignition plug top coil or a coil and module system with HT leads. In both scenarios all of the components of the ignition system including the spark plugs, and the pencil connection lead should be removed and inspected. It would also be useful to employ a diagnostic scan of the vehicle as it will help to rule out any engine management issues such as a faulty air mass sensor or throttle body. It would also be useful to understand if the symptoms are consistent or only happen at certain times, for example when the car is cold.
Switches & Sensors
ABS Warning Light on Land Rover Discovery
I have a 1996 Land Rover Discovery 2.5 TDi. 1 out of 5 times that I drive away the ABS light stays on but most of the time it goes out just after I have pulled away. What could cause the ABS light to stay on?
As a first step, we would recommend that you run a diagnostics check to see if you get any fault codes - this will check that the signal is being received and that the system is functioning correctly. It is also advisable to check that the sensors are positioned correctly in line with the manufacturers' guidelines as these can be knocked out of place. The electrical connections should also be checked, as well as the condition of the sensor itself - if there is a dirt build up, the sensors may not be functioning correctly - if they are dirty, they can be cleaned and then replaced.
ESP Warning Light on Ford Transit
Using our Ford OE diagnostic tool to correct a traction/ESP light illumination on the dashboard of a 2007 Ford Transit, we have no fault found. Clearing the MIL and ESP light from the console and after extensive road testing, the vehicle runs as normal with good power response. However, after a period of time the ESP warning light comes back on and severe power loss occurs. Reset procedures are again carried out with no faults found in the system. One clue that occurs during these periods when the ESP light is on, is that if you start the vehicle and immediately switch off the engine and restart, the ESP light goes out and remains out until the next cold start (usually the next morning) - any help would be wonderful?
To start your investigation, it is suggested that you should check the brake/clutch switch. You should be able to check this out with your Ford diagnostics system on live data. Breakdown in communication with the ECU caused by a faulty switch can cause the ESP to read a fault and when the traction control light is illuminated, the engine goes into limp mode and limits the power.
If this does not help, check that the tyre size is correct to the manufacturer's requirements, as the reading of the ESP may not be accurate when the size is incorrect.
Mini - Lack of Power on Start-Up
I have recently fitted a front wheel bearing on a new Mini and now the car has no power when first starting - switching it off and on rectifies the problem, but the initial start-up is still an issue.
It is likely that the ABS system is registering a fault and cutting the power. We would advise checking the positioning, condition and cleanliness of the ABS sensors and also checking for any ABS related fault codes. If the sensor positioning is correct, any dirt is cleaned away and any other faults are cleared down we believe this should rectify the problem.
Toyota Celica Over Fueling
I have a 2002 Toyota Celica in the garage at the moment, and it's massively over fueling. The injectors are open to the upper limits and I can't seem to find out why. I've tested the MAF and it seems to be giving me a decent wave form. I'm using a Delphi DS150 which is producing no fault codes and a Pico scope to check voltages and waveforms. The only thing I have got is no switching of either Lambda sensor, but I'm not sure if this due to the over fueling. I am also the third person to take a look at it and they can't seem to figure this out. Just wondering if you may have any information that might help?
We would suggest that this does sound like a Lambda sensor fault. Alternatively, there could be an air leak - this can be investigated by spraying brake or carb cleaner over the air pipes and listening to see if the revs pick up (as the engine burns the alcohol from the spray).
It should also be noted that the Delphi DS150 does not have the function to fully communicate with this vehicle due to Delphi's coverage of Japanese cars and also the age of the car - it is recommended that you use a 'Launch X431' or a Bosch diagnostic tool for this application.
If this does not help, other areas to check would be engine timing and the condition of the catalytic converter.
Booming Noise on Astra Diesel Engine
I have had a customer bring in a 2005 Vauxhall Astra diesel and they are complaining of an unusual noise that is coming from the engine. After an inspection of some of the key engine components, we cannot see any obvious faults. Could you suggest any further checks before we investigate further?
On some Vauxhall Astra and Zafira models from 2005 onwards, Vauxhall started installing a vibration damper in the production process to minimise vibrations and noise from these engines. Not all vehicles will have been fitted with this damper so therefore we would recommend that you check whether the front sub-frame has been fitted with one. If the vehicle in question does not have a damper then one can be retrofitted using OE part number 24459603. If this does not resolve the noise issue, then a further inspection will be required.