No Idle on 1.9dg Petrol, but fine on LPG

[crazyhorse]

I loathe to start another topic on this but here goes...

So In the light of dwindling LPG stations in south wales I have decided to try sort an ongoing problem with the petrol side of the van..

I rarely use petrol and I have always had a problem with warm idling... It just wont do it.. Usual scenario... junction, clutch down etc, it will just die...

I thought id give it a go and buy a rebuild kit and after following the instructions by CJH, James and various forum posts gave it a go... All went well, and I even managed to sort a hesitation issue by doing the  Accelerator jet and measuring delivery.

But the idle issue still remains... It idles perfect on LPG but just wont on petrol..

When the engine is idling on LPG i can hear a small hissing noise (is this normal) or maybe I am just too used to the noise that my mind is playing games with me...so maybe there is a vacuum leak... but I just cant see where..  I obviously cant do it on petrol as it wont idle... I have tried spraying around the carb to notice a change in sound but nothing...

Anybody have any ideas before i take it to a professional for silly money...

I have changed filter, and even replaced the fuel tank (not only because of this), has an electric pump..

Go easy on me...

[Mocki]

On petrol, are you sure it’s only on petrol? Its not unknown for dual fuel systems to run on both when they should only be on one , admittedly it normally petrol not shutting off totally and adding some petrol through on LPG , but its worth checking . 

Switch the lpg off and run til the engine stops , then start it again to be sure no lpg …….   
Start it on petrol, and hold the idle up ( brick on throttle pedal ? ) to the lowest it will run , then spray carb cleaner / brake cleaner around the inlet manifold , one end at a time , if there is a induction air leak it will increase revs as it drinks in the carb cleaner briefly , repeat this round all the vac pipes and both ends of the inlet manifold , if its leaking you will hear it increase the revs , don’t mist it everywhere and avoid the air intake obviously . 

[TwinTurbo]

my money would be on the fuel cutoff solenoid

[crazyhorse]

On petrol, are you sure it’s only on petrol? Its not unknown for dual fuel systems to run on both when they should only be on one , admittedly it normally petrol not shutting off totally and adding some petrol through on LPG , but its worth checking . 

Switch the lpg off and run til the engine stops , then start it again to be sure no lpg …….   
Start it on petrol, and hold the idle up ( brick on throttle pedal ? ) to the lowest it will run , then spray carb cleaner / brake cleaner around the inlet manifold , one end at a time , if there is a induction air leak it will increase revs as it drinks in the carb cleaner briefly , repeat this round all the vac pipes and both ends of the inlet manifold , if its leaking you will hear it increase the revs , don’t mist it everywhere and avoid the air intake obviously . 

Thanks Steve...

Will do this tomorrow and maybe record a video...

90% sure its only on petrol when switched to petrol..
 

[crazyhorse]

my money would be on the fuel cutoff solenoid

this was a thought also... but it does click when ignition switched

[maxstu]

If it drives at revs on petrol but will not idle then l would dismiss petrol solenoid not working.
However there are two sequences. LPG solenoid and petrol solenoid. Both can be easily tested and are receiving 12v and they are earthed correctly. Also check the position of the manual override switch lever on the petrol solenoid.
I would check whether the electric fuel pump is working effectively and delivering enough fuel. Or revert back to a manual pump and rod set up for testing.
Lastly, set up timing again at 10°degrees BTDC and confirm it has premium unleaded in the tank.

[tobydog]

If it drives on petrol but won't idle then it's not fuel delivery as it takes more fuel to drive than idle?

Not familiar with a dg, does it have an idle jet in the carb? That would be the first part I'd check and clean....

[crazyhorse]

If it drives at revs on petrol but will not idle then l would dismiss petrol solenoid not working.
However there are two sequences. LPG solenoid and petrol solenoid. Both can be easily tested and are receiving 12v and they are earthed correctly. Also check the position of the manual override switch lever on the petrol solenoid.
I would check whether the electric fuel pump is working effectively and delivering enough fuel. Or revert back to a manual pump and rod set up for testing.
Lastly, set up timing again at 10°degrees BTDC and confirm it has premium unleaded in the tank.

Thanks..

Defo enough fuel coming through... have taken fuel feed pipe off at carb and got the electric pump to pump fuel into an empty milk bottle.. nice and steady..timing wise I havent got a clue and dont have the means to test this unless I take it to the garage..

Solenoids working fine I think

[crazyhorse]

If it drives on petrol but won't idle then it's not fuel delivery as it takes more fuel to drive than idle?

Not familiar with a dg, does it have an idle jet in the carb? That would be the first part I'd check and clean....

Thats a good point about delivery...

There is an idle jet which you can screw out and clean any blocked holes... done this with carb cleaner and some posh carb cleaning brushes... still no joy...

[TwinTurbo]

The cuttoff is for the Idle and Progression (just off idle) . It does not affect the primary fuel supply.  Ford did not fit them so they had a screw in blanking plug. 

[crazyhorse]

Seems like it’s getting worse now…

I took carb off and cleaned all the holes etc.. but now on lpg Van will only idle around 2000rpm and can’t bring it down via idle screw… great… when I pull the vacuum hose off distributor it goes down to about 1100 rpm but won’t go down…

Started as one problem and has morphed into another…

I”m stumped and it seems like it’s another problem

[Mocki]

Ok, so back to basics here……..   dont fiddle with settings , they havent changed themselves , its caused by some thing else !!! 
Before you took it to bits again, it idled ok on lpg, now it isnt ? Odds on thats a gasket or seal issue . 
When on LPG the carb is just a funnel, the mixture happens in the vaporiser essentially , so if you have managed to make the idle disappear  it has to be by introducing more air into the mix ( leak) or less air (Blockage) 

[crazyhorse]

Ok, so back to basics here……..   dont fiddle with settings , they havent changed themselves , its caused by some thing else !!! 
Before you took it to bits again, it idled ok on lpg, now it isnt ? Odds on thats a gasket or seal issue . 
When on LPG the carb is just a funnel, the mixture happens in the vaporiser essentially , so if you have managed to make the idle disappear  it has to be by introducing more air into the mix ( leak) or less air (Blockage) 

Thanks… makes sense..
so if I have done something to the carb through refitting it shouldn’t effect idle?? Even if fast idle cam isn’t working as it should