LPG bit the dust after headers & decat installed...

Just fitted hedman headers and the obvious decat Y pipe but still has lambdas installed in both sides.

Now before i did that it was running fine on both petrol and gas with power pretty much identical.

Now it goes like **** off a shovel on petrol and is absoloutely ****e on gas, done 50 miles tonight, it popped, it banged, it missed, it felt laboured, sluggish, lumpy, all noise and no get up and go, rough & nasty.. Can also smell gas from around the vapouriser.

Switch back to petrol, absoloute beast, but with a small intermittant lumpiness at low revs but once its going its not stopping.

All this has happened since i removed the cats and installed the headers, the leads and plugs are all BPR6ES and Genuine Bosch, Gas was fine on these before the header install.

Im stumped, any ideas... Thankyou.

put it back to standard and see if it runs properly ?

Thats too much of a task mate, i dont fancy it one bit. Can a faulty lambda plug have any ill effect on running on gas? Im just thinking i may have knackered one somehow.

Either that or its ignition related, or the gas system needs retuning to suit the headers, With the bonnet open, i was revving it on gas with the throttle linkage, sounded very laboured and tired, missus sat in the cabin she switched to petrol, same thing, revving it via linkage, revs very strong, sounds like a mustang, switch back to gas, revving it, sluggish, laboured, its only gone like this since i removed the cats and fitted the headers, better on petrol, worse on gas, it was the other way round when i bought the damn thing.

If you de cat it - is the vehicle cat test age, if so it will fail

Running lambda there are no tune resistors from memory- ign off pull battery for 10 mins see if it resets ecu fueling.

Regards gas thisay need plugging in to alter fuel trims

fanatic said:

If you de cat it - is the vehicle cat test age, if so it will fail

Running lambda there are no tune resistors from memory- ign off pull battery for 10 mins see if it resets ecu fueling.

Regards gas thisay need plugging in to alter fuel trims

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Yeh, it has 11 months ticket on it so im ok for a while, got the cats here when the time comes, i will remove battery tomorrow to reset everything, im thinking water contamination somewhere in the ignition system, i'll have to go over everything i can think of, slight misfire at low revs on petrol has developed since the header install, although i think it could be water contamination somewhere along the line as i did the job in a downpour, could be alternator, my sidelights dont just light up, they light up like you would turn a dimmer on slowly. The fun begins i suppose.

Battery off for 30 mins, stepper motor cleaned, lambdas are all connected proper, checked leads, coil connections, etc, all tight and secure.

Still the same.

Seems like 9 times out of ten its ok on petrol and the tenth time it will be sluggish, (as if a plug is fouling or a weak spark) but then clear up after 3-4 seconds.

9 times out of ten its a bag of crap on gas and the tenth time, it might go ok, (feels like its down a cylinder)

Cant work it out, it was fine before the header change, full throttle on gas it will bog and if throttle is kept open it will go bang, and the odd time it will be ok.

I suspect you may need to advance the timing a bit - very complicated as to why - just give it a try

griffman said:

I suspect you may need to advance the timing a bit - very complicated as to why - just give it a try

Click to expand...

I think my vacuum advance module has gone, i can suck and blow on the pipe with no resistance. See what it goes like on gas after i change it.

Thought i had found the problem though, the T piece for the water pipes to the vapouriser was leaking, drops of water directly into the ht lead of cylinder 4, seems that wasnt the fault, all plugs seem fine albeit a little sooted.