Engine Protection Units | Exhaust Gas Temperature (EGT) Guage

Theoretically it shouldn’t, but it does, especially when the vehicle concerned doesn’t have an altitude compensator fitted.

The altitude may not affect boost pressure, but it definitely does affect the air fuel ratio, which is directly proportional to EGT.

Many of today’s diesel turbos don’t have altitude compensators.

If a vehicle is set up with 10 lbs of boost pressure at a certain rpm and for some or the other reason the boost decreases due to a hole in a pipe or cooler, the air fuel ratio is affected and once again it is directly related to the EGT.

On vehicles with electronically controlled boost compensation, the difference is not as big but is still present. Electronically controlled systems may also pick up a lack of boost pressure, but 90% of the bakkies on the road today are not electronically controlled.

Fuel from 5 different pumps gives different EGT readings.

In our opinion, only the viscosity or lubricity of the fuel changes slightly and as a result the pump’s automatic timing, changes, which result in rapid EGT change.

This is a very delicate area, simply because a small variance or incorrect setting could result in 200º EGT change.

The settings which are usually done in a "Pump Room" nine times out of ten change when the pump is exposed to the under bonnet conditions.

We find it very difficult to understand why controlled conditions are used when setting up a pump and then the pump is fitted to an engine, which does not have controlled conditions, in fact it's everything but controlled under the bonnet of a vehicle.

You could purchase a brand new vehicle and the settings of the pump under the bonnet could be incorrect, which results in extreme EGT's and ultimately into a slow process of engine destruction.

Here we have a situation where the water temperature can differ up to 15ºC and the temperature gauge in the vehicle will not move from the normal position.

This is how the cars are built and unfortunately 15ºC has a huge affect on the EGT.

Here with electronically controlled pumps, the problem is far smaller but again 90% of the diesel turbo vehicles on the road today are fitted with mechanical pumps.

The EGT is very easily affected if the pump timing is incorrect.

Many factors can influence the pump timing, because the advance function is also mechanical.

Many other factors can influence EGT and we won't be able to go into detail in each case but to list a few which are most common:

As we said before, they all create a snowball effect and the problem is, one will never know when most of the above are happening.

A simple gauge, which can monitor EGT, will indicate immediately if something is wrong.