Stalling and bad idling. Any ideas?

[Dave n Kate]

I have a 2l 2-wheel-drive notV6 Bongo with LPG conversion.

When running on LPG everything is fine and the engine idles okay.
When on petrol, the engine doesn't idle very well, it revs up and down ranging from around 1500 to 500 revs then when you press the accelerator the revs drop right down and sometimes stalls the engine. If you accelerate quickly it doesn't stall, but when inching out of a junction, it's a problem.

Luckily the Bongo is still under warranty, but before I take it in, I'd prefer to have an idea what the problem might be.
Any ideas??


Thanks
Dave.

[Simon Jones]

Have you tried loosening the petrol filler cap when this happens as there can sometimes be a vacuum or pressure build up in the tank? It could also be fuel pump issue, injectors or problem with the mixture. At least it's fine on LPG so that suggests the ignition is in good order. My BRC LPG conversion effectively 'piggy backs' off the main ECU, so uses all the sensors on the engine including the lambda sensor in the exhaust to ensure the gas/air mixture is correct. Other LPG systems may be different, so its possible your lambda sensor is faulty, but the LPG could be masking the problem if it does not use it.

What LPG system do you have, and do you have FlashLube (manual or electronic)? Some people have suggested that FlashLube can have a detrimental affect on lambda sensors, although its cheaper to replace a sensor in the event of a problem, than 24 valve seats in the case of the V6.

[Dave n Kate]

Hi Simon, thanks for the suggestions.
I tried loosening the petrol cap but no change. The engine is only hunting (I learned a new word) a little bit now.
The Bongo wasn't quite right from purchase but the garage said it was caused by a broken Cat' which they replaced the other day, sadly, though the cat obviously was what was causing all the rattling noises, the bongo still has the symptoms listed above. ie.
Blowing. Smokey exhaust, smells fuel-rich and spitting tiny droplets. but all fine when LPG is on.
when revving gently, engine cuts out. You have to rev quickly to get past the flat spot.

My LPG is a BRC 'Time.' I think it is a very early (1999) and primitive model single point. It has no flashlube. Probably way past its sell by date but still working fine.

I'm going round to see the seller now. See if he'll sort it.

Cheers.
Dave

[mikeonb4c]

Whereabouts (roughly) do you live by the way, in case there's a BF expert nearby.

[mikeWalsall]

You will (should) have a full sequential LPG system on your Bongo ..

[Dave n Kate]

Spoke to the seller, he's making the Bongo an appointment at the garage Mon/Tue so we'll see what they say.

mikeonb4c: Hi, thanks, we live in Llandudno N.Wales. Are there any Bongo experts in this part of the world do you know??

mikeWalsall: Hi, thanks for the input. I don't know much about engines. i posted on an LPG forum for advice and was told...
Not too well up on the numerous different BRC systems and have never heard of a BRC TIME. However, an install date of 1999 and a 3 position switch means you have got a single point system fitted to carb and early petrol injected engines.

I get the date of 1999 from a sticker on the ring tank that says ... 57ltr ring tank ASM gas project 16/3/99 which may or may not be the time the system was installed but it's all I have to go on at the mo. I need to study the engine and work out how to tell the difference between LPG systems.

Thanks all
Dave