Intermittant lumpy idle when hot

[adscatt]

Hi everyone, got back yesterday from 4 night's away near Barmouth, Wales, on the way home we detoured to visit family on Anglesey, just before crossing over to Anglesey we got stuck in traffic, it is then we experienced a rough idle, revs dropping to approx 500 then a struggle back up to 800 ish, fine again when revved up but then lumpy when left to idle, carried on to our stop fine no problems when stopped again, fine all the way home even when stuck in traffic on the M56 until pulling up at home and it did it again when manouvering to get onto the drive, it appears to clear when shifted to neutral.

Not had chance to have a look yet as it started behaving again.

Any thoughts as to a possible culprit.

I must say other than this the drive was ace.

[Northern Bongolow]

is it a diesel.

[rita]

Always worthwhile changing the filters and cleaning the banjo and tank filters. Also try running with the fuel cap Off or very Slack..

also check to make sure that the warm up valve/flap is not sticking (If you have the Winter Pack)

[mikeonb4c]

is it a diesel.

Indeed. Diesels generally steady as a rock, v6 less so from some reports

[adscatt]

Hi, yes its a diesel, not got the winter pack, I changed the fuel filter when I bought the van, I haven't done the banjo filter yet. What are the symptoms of the fuel system creating a vacuum? Or does it pressurise?

The only thing is it only did it twice in nearly 200 miles!

[mikeonb4c]

Hi, yes its a diesel, not got the winter pack, I changed the fuel filter when I bought the van, I haven't done the banjo filter yet. What are the symptoms of the fuel system creating a vacuum? Or does it pressurise?

The only thing is it only did it twice in nearly 200 miles!

You could try running with the fuel cap off just to see if it improves?

[chipvan]

air ingress.maybe fit a bit of clear pipe to see if got air issuies

or run bongo off a seperte fuel can just to test

[Northern Bongolow]

had one similar to this that a few garages had worked on but did not fix.

try cleaning the tank filler vent at the 6 oclock position at the tank cap when the cap is removed. clean with a length of wire or foot pump.

take of fuel supply line to filter housing from the tank and blow back gently to the tank to clear filter in tank.

42-590a in this link below is the tank breather, it clips to the inside chassis rail near the fuel filter, pull it off the chassis and clean out, if you look closely at the picture there is a tiny one way valve just inside the pipe, remove this and clean and test.
http://lushprojects.com/bongopartsmk2/c ... mgno=.html.

if non of this cures it it could be the front nose seal on the fuel pump, these let in air when ticking over or make the motor hard to start as the fuel supply is upset.