Slow engine response

[03Sedona]

Hi there! I own a 2003 2.9 diesel a/t Sedona. Recently I noticed there is a delay in engine response when you step on the accelerator. When parked and on idling, the engine seems more noisy than normal. What could be the problem? Would appreciate your help. Thanks.

[westj66]

Hi,

A diesel engine likes lots of cool air charging the cylinders and an un hindered exit for the exhaust gas. If there is any restriction in the exhaust system you will have too much back pressure, the turbo will not spool up as it should resulting in lack of response and ultimately greater heat build up. As the engine is not revving freely it can become noisy. What is the milage on the clock if it is high then I can safely say the inlet manifold is full of sludge, the intercooler will need cleaning inside and out and if a lot of short journeys are made, the cat could be clogging up to.

My 03 Sedona has a similar problem. I have already blocked off the EGR pipe, my next job is to modify the cat to a straight through pipe and to clean and move the intercooler from the top of the engine to the front directly in the air flow (as on the new Sedona!!). these two mods will not only make the car more resposive but by reducing the temp of the mix to the cylinders, improve the power output. More power and turbo response means less throttle opening required and therfore better economy.

If you are not sure try going onto any of the VW forums and check out the mods being done to them, it makes very interesting reading.

Hope this info has been useful, good luck.

[03Sedona]

Thank you for the input, westj66. I will look into those mods you mentioned. Actually, my mechanic was able to sort out the problem yesterday and it was a combination of a dirty fuel filter and a timing belt that jumped off one groove making it retarded from the right setting. This was caused by a defective idler bearing/s. Now that the timing belt, idlers and fuel filter had been replaced. It's now running fine as it used to. But definitely I'll look into your suggested mods for better performance. I like the feeling of having extra power.

[westj66]

Yes the timing belt won't have helped, it could of really messed things up if it had jumped any more teeth.
It's always hard to say what is causing a noise unless you can hear it. My 03 now has 111,000 miles on it so is due for a bit of TLC in the gas in gas out department. My noisy engine and sluggish performance is due to build up of unwanted deposits in the system.
I am glad everything is sorted for you as overall they are a good solid car with bags of room.