Thread: Occasional slight hesitation

Originally Posted by Markf

Just got back from a short trip away to Omeo and back to Moe towing the camper at about 1.8tonnes.
On the way back there was a strange little issue. Occasionally at full throttle (or very nearly so) at around 2500 to 3000RPM there were a few very short duration hesitations. On one occasion immediately after the hesitation there was a LOUD whine/screech (in 4th gear at about 2800RPM) which went away as soon as I got off the throttle and changed to 5th. It never reappeared and in retrospect didn't sound mechanical. At least I don't think it sounded like a gearbox or transfer case about to eat itself.
A cursory squint around revealed that the intercooler to inlet manifold hose was quite hard and the flexible hose leading into the intercooler is very soft. I also noticed that the hose from the turbo waste gate boost control valve to the intake hose is missing. The engine response is subjectively (with only a "feeling") more sluggish than it used to be below about 2000RPM.
According to the service/repair record that I have for the car (extremely detailed) the turbo hoses were replaced around 200k km ago.
Question is given the scant information provided is it reasonable to replace the turbo hoses, the hoses to the turbo waste gate boost control valve and the turbo waste gate boost control valve? If it is reasonable do I go for standard hoses or the silicone hoses?
I'd have more info IF I'd had time to take the hoses off and have a good look.

Check injector harness for oil seepage and electronic waste gate do you have a nanocom or such to read boost pressure?
Also could be clutch slippage main reason I've heard for that is the fuel pressure regulator leaks and drips on the fly wheel but it only really happens when its been raining a bit

Originally Posted by Star667

Check injector harness for oil seepage and electronic waste gate do you have a nanocom or such to read boost pressure?
Also could be clutch slippage main reason I've heard for that is the fuel pressure regulator leaks and drips on the fly wheel but it only really happens when its been raining a bit

FPR was replaced at the same time as the clutch about a year ago and is as dry as a bone around that area.

The injector harness is also pretty new - around six months old and no sign of oil in the connectors. My first thought was "bloody injector harness" so that was the first thing I checked.

Boost pressure is currently unknown until I can get my hands on a Nanocom (must get one of my own) over the weekend.

Given that one of the nipples is broken off the waste gate solenoid I reckon that's worth replacing anyway.

In my wildest imaginings I would never have thought of the clutch although the hesitation doesn't feel at all like clutch slippage. It's more of a momentary loss of power for a VERY short time. The thing that pointed me to turbo hoses was the single episode of the whine / screech at around 3000RPM which was very loud and stopped immediately I got off the throttle. I think that it could have been possibly a screech of air escaping or screeching past a partial hose blockage.

Of course the car's behaved perfectly well today although it "feels" a bit more gutless than in the past at low revs. But it is a Td5 after all...

Originally Posted by Markf

FPR was replaced at the same time as the clutch about a year ago and is as dry as a bone around that area.

The injector harness is also pretty new - around six months old and no sign of oil in the connectors. My first thought was "bloody injector harness" so that was the first thing I checked.

Boost pressure is currently unknown until I can get my hands on a Nanocom (must get one of my own) over the weekend.

Given that one of the nipples is broken off the waste gate solenoid I reckon that's worth replacing anyway.

In my wildest imaginings I would never have thought of the clutch although the hesitation doesn't feel at all like clutch slippage. It's more of a momentary loss of power for a VERY short time. The thing that pointed me to turbo hoses was the single episode of the whine / screech at around 3000RPM which was very loud and stopped immediately I got off the throttle. I think that it could have been possibly a screech of air escaping or screeching past a partial hose blockage.

Of course the car's behaved perfectly well today although it "feels" a bit more gutless than in the past at low revs. But it is a Td5 after all...

Can you possibly repeat the symptoms at a stand still? I believe the turbo still spools at a standstill

Boost modulators are cheap , I just replaced mine got it from Roverlords

It wouldn't be an idler or the fan bearing , or something on the belt momentarily seizing then releasing would it. I would inspect all the idlers and pulleys closely by taking the belt off and checking them all by rotation.

Regards Philip A

Over the weekend and tonight everything has been inspected to within an inch of its life. It was helped by having a Nanocom available for a very short while tonight.
Boost solenoid is faulty. EGR inlet is stuck open. Turbo hose to intercooler is delaminated a fair bit.
Of course while the nanocom was plugged in after the faults were cleared there were no faults logged and I was unable to replicate the issue.
I have a boost solenoid which I'll change over tomorrow, a set of silicone hoses are on the way and I have an EGR delete kit in a box somewhere in the shed.
All pullies that the drive belt runs over are free running with no harshness so that's all good as is the injector loom which is bone dry at both ends.
AND I'll have a Nanocom on its way in the very near future.

Thanks everyone for all your suggestions - it appears I have more than one fault and yet the car still goes well.

What was the faults that were logged?