BRC Intermittent Misfire

[a137699]

I've got a BRC Sequent system on my Zafira GSi 2.0 Turbo 16v (2003). It's been on for nearly 100,000 miles. However in the last week or so, I've had misfiring when running LPG - most notable when going up hill or turning sharp corners.

The car runs fine on petrol.

I've had injectors go down in the past, but when they did, they just stopped working completely - car ran 3 cyls and EML light came on.

This one is an intermittent fault - and I'm not sure whether it's worth spending £100 on a new injector and changing them 1 by 1 to see if it elminates, or if there's another possible explanation?

BTW the system was serviced by greenfuel just 3 mths/ 2000 miles ago...

Any ideas?

[rossko]

I can't find it, but there was a post with exactly the same uphill/bend symptoms a while ago ... the cable to the tank had fallen to the exhaust and got scorched, as it swayed about it would short and 'blip' the tank valve...

Which is to say, I wouldn't randomly change injectors on spec. Injectors do wear out, but generally reveal as roughness on idle or light loads, still working good under load.

If t'were me I'd start by looking for an ignition weakness - new coil pack and plugs

[a137699]

Interesting - as the tank was recently lowered to fit a new float valve... don't think it's coil or plug related as it runs 100% on petrol...

[tommo2009]

just because it seems to run fine on petrol doesn't mean there isn't a problem with the ignition system. LPG is a lot more demanding on the ignition system and will show up as a missfire, even though the car seems to be fine on petrol.

when the service was done, was it just an LPG service or were the plugs changed as well, how many miles have you done on the plugs that are in the car.

[a137699]

The LPG service was done 2000 miles ago (changing the LPG filters etc.). The car service was done 4000 miles ago when brand new plugs were fitted (part of a major service).

It can get so bad that the car simply refuses to run up a hill on LPG (revs drop, car stutters), but then immediately flicking the switch back to petrol the engine immediately restores power and away you go.

[tommo2009]

What you describe doesn't sound like a missfire but lack of fuel or possibly a Vacuum pipe not connected.
you are going to need diagnostics with live data and get the vehicle to do it while the diagnostics are connected.