1. Vibration on steering wheel

A problem that the both of us (Vish and Trev) have found on our cars is that we get this strange vibration on our steering wheels at about 100km/h – 120km/h…..BUT this vibration is only present under acceleration. After consulting with the VW agents, it seems that this is a problem on a lot of the Golf 4’s, and although it sounds like it may be an unbalanced drive shaft or something similar, we have been told that it is just the ‘feel of the engine coming through on the steering wheel.’ The vibration is actually not that bad, and we figured that we’d be better off living with it rather than getting someone pull off the drive shaft!!

2. ‘Buzzing’ sound when opening driver side door

This is a sound that a lot of people often enquire about on VW bulletin boards, and can best be described as follows:When the car is parked for a bit of time (a few hours perhaps) and the driver’s side door is opened, a sound that is similar to a small DC motor turning is heard. There have been many attempts to explain this, but the one that seems to make the most sense is that the fuel pump is actually pressurizing before the car is started so that starting the car becomes easier.

3. Electric windows having a mind of their own…

Another odd characteristic that we have noticed on both our cars is that when the car is stationary, and the automatic window close (i.e. the second ‘click’ on the switch) feature is used, the window seems to go up for a while, and then automatically comes back down again. Now, this is one that VW cannot seem to work out, but the best explanation is that the obstruction sensor on the window may for some reason feel that there is something in the way, and as a result, brings the window down a little. This seems to happen only on the front windows.

There are many people out there who complain of some parts going defective after being chipped. The most common of these is the DV (diverter valve) failing, or the MAF (Mass air flow) sensor going bad. However, since I (Trev) have been chipped, none of these parts have given any indication of going bad……there are some other ‘characteristics’ of modding that I have experienced, and these are described below:

1. Surging

This is probably the most hated result of chipping, and seems to be a universal issue. Basically, what surging feels like is that when maximum acceleration is demanded, the car feels like it gets that acceleration for a second or two and then backs off a bit, and then gets it again, and backs off again….and so it goes on until a certain RPM band is passed, or the driver lets off the gas pedal a little.

There have been a number of theories on this too, and some of them include the DV and MAF (once again). These may in fact be causes of the surging also, but in my personal experience, the real problem is that the wastegate on the turbo is actually getting confused as to when to open and close at the right times….it can be thought of as the turbo and the wastegate not being in synch.

Initially my car used to surge, and this lasted for quite a while, but after scouting around and looking at various bulletin boards, I tried something that seems to have worked a little(Thank you VW VORTEX). Basically, there is a mechanical valve/solenoid in the 1.8 t engines called an N75, and this valve controls the opening and closing of the wastegate. How it works is that the ECU sends out an electronic wave to the N75, and the duty cycle of this wave determines how the wastegate opens and closes. In other words, the N75 converts the required boost from the ECU to actual boost on the turbo by controlling the wastegate.

Now, the N75 has a stock or factory setting that is probably set to meet the required STOCK boost. When a car is chipped, the required boost is higher than the stock boost, and this is where the problem comes in – it seems as if the N75 has to be adjusted to accommodate this new boost. This is done via a small screw that is on the N75. The picture below shows a picture of the N75:



NOTE 1: This picture is courtesy of VW VORTEX (WWW.VWVORTEX.COM)
NOTE 2: Ignore the colour markings on the picture – they were used in the VWVortex Bulletin board to indicate adjustment positions.

Disclaimer and warning: Please bear in mind that if you are experiencing surging on your car, do not attempt to adjust the N75 on your own. There are 2 reasons for this:

1. If you adjust your N75 so that your wastegate is permanently shut, you run the risk of developing too much pressure in your turbo and thus blowing it.
2. Some of the people on VWVortex complain that they have broken their valves as these valves sometimes are stuck or glued into one position.

2. Exhaust Backfire

Another problem experienced once removing the cat converter was that a quite audible back fire was often heard on changing gears. Although this was the cause of much worry at first, the most reasonable explanations I received were these:

1. Due the chip being remapped on the car for more power, the car sometimes runs rich (rich = extra fuel). Consider driving the car at a certain RPM, and lets assume that at this RPM there is excessive fuel in the exhaust. Now, if the accelerator is released (for a gear change e.g.), and this excess fuel is still in the exhaust line, and the accelerator is again pressed (after gear has been changed), then a spark will be produced, and this spark will ignite the excess fuel, resulting in a ‘bang’. This sound is not always heard, and it depends very much on the way in which the car is driven – if the accelerator is sharply tapped after gear change, and there is excess fuel in the line, then it will be heard. However, even if there is excess fuel in the line but the accelerator is smoothly pressed instead of being tapped on, there will be no backfire.
2. The second explanation is that the catalytic converter also acts as a muffler, and when it is in, this sound will be muffled – hence chipped cars with their cat converters still in do not make the sound.

3. Pinging

Another common problem associated with having a 1.8t chipped is pinging. If you do not know what this is, try doing the following:

Take off in your car in first gear, and then change directly to fifth gear. The ‘rattling’ sound you hear is actually pinging.

The reason that some chipped cars suffer with pinging is that when chip tuners do a chip, they actually advance the timing to produce a little more power. Pinging has some nasty effects, and has been described by some as the ‘worst thing for an engine’.

Pinging can cause your pistons to crack, or even burn a whole through your piston if it is bad and chronic enough. The only ways to stop pinging are to set back the timing (which will decrease power a bit) OR to use a higher octane fuel.