Club 80-90 Forums

I know this is a fairly well covered topic but I'm lost, when running on petrol my van is really hesitant to idle, even once warm. Tends to cut out at lights and such. Its also quite spluttery and hesitant at low revs.

However, on LPG it runs like a dream, pulls really well, but idles quite high!? Although it does smell rich on gas.

To make things even more confusing, the carb has had the choke mechanism removed, a local carb specialist did away with it as it was inactive, and to be fair to the guy who has an awesome reputation, it transformed the thing when he first did it.

The idle problems on petrol have been occurring for the last couple months since its been sat up over winter, however the fast idling on gas has only just started occurring.

Its just occurred to me the petrol issue could be down to blocked jets

Stripped the carb this eve, well split the two halves and thoroughly cleaned everything. Tweaked the odd bit following a couple of awesome guides one the wiki. Chucked it back on the car. Won't fire. Float bowl is full. Throttle is chucking fuel down the inlet but no vroom...

Keep us posted James if you manage to fathom it, as I am having similar problems with my petrol/LPG 1.9 DG.

amiiwu wrote:Keep us posted James if you manage to fathom it, as I am having similar problems with my petrol/LPG 1.9 DG.

I'm hoping it's a combination of a grubby carb from being sat idle over winter, and it being slightly out of tune. Carb is on the workbench again atm.

Finally got it to start, I'd knocked the wire block on the side of the carb, hall sensor is it? Wiggled that and fired up. Revs much better on petrol now, even when cold with no choke mech. Will report soon as to how it drives and behaves once warm. May have to further tweek the idle stop screw though.

JamesKT25 wrote:Finally got it to start, I'd knocked the wire block on the side of the carb, hall sensor is it? Wiggled that and fired up. Revs much better on petrol now, even when cold with no choke mech. Will report soon as to how it drives and behaves once warm. May have to further tweek the idle stop screw though.

No hall sender on the carb that's on the distributor.
On the carb is the idle speed cut off.
It's a safety device that prevent the engine idling after the ignition is turned off
LPG doesn't use it.

Sorry I meant on the side of the dizzy.

I've got the carb all back together but managed to snap the throttle nozzle so waiting on one in the post. Chucked it back on the van and fired it up on LPG but its seems to be missing at low revs, my thought is an air leak as it sometimes backfires and dies.

Will report back when nozzle is fitted and I can run on petrol.

That'll be me sending it then

one of the best things for diagnosis and tuning I ever fitted was an air fuel gauge.

Needs a lambda sensor fitting in the exhaust but gauges can be bought cheap and it tells you if its rich or lean.
Rich cost you fuel, lean cost you potential engine damage.

Running lpg without one us a guessing game, running an old carb without one is alsoa guessing game.

in fact I'm just readjusting my lpg again, tiny adjustments on the vapouriser and power valve can be seen, over a number of days and trips I can adjust it to be good for all driving conditions. LPG drifts over time and your installer never spend days tweaking it so it may never have been right from the start (mine wasn't)

If your lpg is set to idle too high by the bypass screw your throttle stop position screw may be set to compensate making it idle too low revs on petrol.

kevtherev wrote:That'll be me sending it then

Received it yesterday! Thanks again dude!

I want to try and reduce my LPG usage until I can get the system properly serviced and re tuned. So getting it to run well on petrol is a must. To my knowledge, the LPG hasn't been touched or tweaked in nearly 8 years! Not many LPG specialist up here near Scarborough!

itchyfeet wrote:one of the best things for diagnosis and tuning I ever fitted was an air fuel gauge.

Needs a lambda sensor fitting in the exhaust but gauges can be bought cheap and it tells you if its rich or lean.

Can you link me to that gauge, on the old interwebs? Found a couple but they seem to be vacuum operated? no mention of wiring a lambda?

just bought this one for my other petrol injection van but not fitted it yet

http://www.ebay.co.uk/itm/52mm-Air-Fuel ... SwofxUfFAy" onclick="window.open(this.href);return false;

search ebay for air fuel gauge 52mm
search ebay for universal 4 wire lambda sensor
search ebay for lambda boss

itchyfeet wrote:just bought this one for my other petrol injection van but not fitted it yet

http://www.ebay.co.uk/itm/52mm-Air-Fuel ... SwofxUfFAy" onclick="window.open(this.href);return false;

search ebay for air fuel gauge 52mm
search ebay for universal 4 wire lambda sensor
search ebay for lambda boss

Awesome thank you. I kept finding gauges but non were mentioning a lambda, most just had vacuum hose attach
ments.