Diesel problem question

[UrbanRedneck]

Hi all another question on 97 GQ RD28T diesel.

The problem is that at low RPM low throttle say cruising through town (between 1300 and say1500 ) the bloody thing surges quite rapidly like a flutter. You cant actually see it on the tacho but feel it ,and is very annoying.
I was told it may be an air leak in the fuel system or a non return valve in the pump not doing its job.

Just after some opinions on possible causes as a pump rebuild will kill me.
and i have grown quite fond of the little donk.

Thanx in advance Damo

[bogged]

Who told you it had an airleak?

[UrbanRedneck]

He said it may have an air leak but just wanted to see what other people think.
I mean i have no reason to doubt him as he is a CAT mechanic just thought i would see other opinions.


Also it has quite a miss at start up unless glowed 3-4 times(has new glow plugs) and little bit of hazy smoke at idle till hot.
The bottom end is 20k old but did re use the head and turbo 260k.
It also has reco injectors around 5k old.

[canuck]

After your new info about starting, it sounds exactly like an air leak. A likely spot is the filter assembly but it could be anywhere. Look for a diesel leak - often just a damp spot. Sometimes there is no apparent diesel leak. I think it is easier changing out all the hose than just looking for a pin prick of a hole or crack.

[tweak'e]

fit a bit of clear fuel hose, you will soon see the bubbles. unless of course its the pump seals.

[garth]

As above ..but check the injector return/leak off lines as they are very fragile and often fracture when installed or removed, I had same symptom and found crack at the leak off disk at one of the injectors.....silver soldered it back on and alls good....

good luck

[UrbanRedneck]

Thanx guys very helpfull shall be looking for leak this weekend.