Ask Dave / Posted 3 years ago / 904 views
Question: I have a cat C-9 in my Beaver Contessa and have noticed a loss of power, the CAT dealer says I have two bad injectors. I only have 60,000 miles on the coach, shouldn’t injectors last longer than this?
Submitted by: Ralph Kent, Lima OH
The problem with your injectors is probably not with the engine but with the fuel system. We have seen several cases of Fuel Line hydraulic hose failure, especially in coaches manufactured prior to 2005. Point of interest to further explain concern, low fuel pressure can cause low power. Low fuel pressure can also cause cavitation of the fuel which can damage fuel injectors. The following conditions can cause low fuel pressure. Plugged fuel filters, Debris in check valves for the priming pump. Sticking fuel pressure relief valve in fuel transfer pump. Debris in return pressure regulating valve in the fuel filter base or adapter assembly. Pinched fuel lines or partial open fuel lines.Old fuel lines that have a reduced interior diameter that was caused by swelling. Fuel lines with deteriorating interior surfaces. Looking at many , many posts about coaches in the repair shop and it seems replacement of injectors number 5 or 6 is a common problem. Why number 5 and 6 injector,s because there are at the end of diesel fuel line. It seems that repair facilities are replacing these injectors without addressing the fuel system, which in most cases is the root cause for low power. Replacement cost for injectors for C-12, C-9 engines is not cheap. We need to look at our motor homes and see if we need to update our fuel system to avoid down time and additional money outlay. New fuel lines are cheep compared to the cost of new injectors.
Fuel line problems are starting are to pop up with age and miles. Using plastic lines seems to be the trend on some motor homes. I can see two problems happening with these hoses,
first the hose getting hard and brittle and cracking inside. Second as the rubber breaks down with heat and age, we are going to get flaking of rubber inside hose into the fuel system, which means going through fuel system after the filters. I have mentioned many times most all problems with diesel engines come back to fuel system and it is one of the main causes of low power.