dj problems on petrol

[Ray]

New vw 2.1dj engine runs perfectly on lpg. On petrol an occasional short increase in revs whilst on tickover and an occasional cut out or misfire whilst running. Not much of a nuisance as on lpg now most of time. Engine fitter thought maybe throttle valve or something electronic and difficcult to diagnose. I thought at first it was due to putting diesal in the tank on the way to VF but the tank was drained and the filter changed some 500k ago.
Any thoughts
Cheers

[toomanytoys]

500K (500,000 miles) you have been busy.... or do you mean 5000 miles

could be any number of things.. but a sticky/non functioning injector or poor connections on ecu/injectors, or even the fuel pump not running smoothly... all needs carefull going over I should imagine..

otherwise the new engine has been going well then Ray?

[HarryMann]

all needs carefull going over I should imagine..

What he said...

Andy McClements had something similar a while ago, think the fuel pressure regulator manifold pressure pipe/tapping might have been blocked, broken or otherwise malfunc. at manifold end

Fluttery idle, hesitation usually weak running
Rhythmic idle, usually rich

New fuel filter around the right way?

poor connections on ecu/injectors

What he said again...

[Ray]

yes engine great now apart this small problem and yes I meant 500 miles.
Thanks for the suggestions. I will investigate further.

[hammy44]

try a couple of tanks of redex petrol treatment through it. it worked wonders for me and mechanics were going to put new pump etc etc etc on fixed it for a fiver myself. by the way mine had new engine fitted too and its a 2.1dj am considering going lpg route would you advise

[syncroandy]

Start off by cleaning or re-making *all* the electrical grounds, then check all electric senders (T1, T2, AFM ) are within spec. Check for vac leaks on the inlet side. Check ISV is not implicated (check it for basic function, clean it out, bypass control unit). Most of these procedures should be in the Bentley.