LPG Discussion Forum

To bash the guts out of some cats you need to cut them open, bash the guts out, then reweld where they were cut.

If the cat has a heat shield then to hide the cut/weld you'd do it where the heat shield will hide it... remove the heat shield to do the decore and refit the heat shield when done ...

Also looking at that link does that mean the cats actually do something in this case and I need them?
Not if you present it for MoT running on LPG. If you take it in running on petrol, it will be tested on petrol, you will need them and it will almost certainly fail the emissions test ...

Nah unfortunately the are solid as but toast af. I can hear the rattle when they get overly hot and they've started to ruin my top end by restricting exhaust gases

Also looking at that link does that mean the cats actually do something in this case and I need them?

I noticed on my MOT test cert it said something to the effect of non catalytic test. Does that mean they don't actually test the Cat?

I ask this because I think these cats are on there last legs, and am fairly tempted to chop em off rather than replace them if they are not actually required since ...

They are very sensitive to false air issues, such leak on the dipstick tube could give problems due to false air entering via the PCV system.

Any error codes returned yet?


nah but this seems to be the issue ive been seeing but not seeing.

before when i smoke tested, i just saw a lot of oil ...

smoke tested the sucker again today, found smoke coming from the dip stick pipe at bottom

https://photos.google.com/share/AF1QipM ... JLN3NrNWFn

Nah no errors but they will come back slowly after like 4-5 tanks. I think it's because its in a certain rev range and the car doesn't spend a lot of time in it so takes a while to pop up. I wanna say around 1200

Yes. Few times, what do I do after that? :p

LPGC wrote: Tue Dec 21, 2021 9:25 am Have you got the correct spec wide band lambda probes fitted?

i assume wide means precat? But yes, from dealer.

I know you're busy, its why am curious if theres anyone else around that might fancy it. It's defo a diagnostic job.

I can clear the trims, and once learned depending on the rev range they can vary from close to 0% to 20%. I think theres a specific rev range that actually gets Lean bank 1 error to ...

Right am out of ideas.

I have a L320 SC 4.2.

It has lean fuel trims on petrol. I can't figure out for the life of me why, like fuel trims well in excess of 10%. It's been smoke tested, injectors cleaned, fresh fuel pump/fuel filter, new genuine MAF.

It also has an LPG installation. I'd ideally ...

On the "Got to wonder why you never got the high fuel pressure error when running on LPG in the past though?"

I noticed something like that with mine, I've a feeling maybe it was setup like 1 injector runs petrol to avoid that. Or the ECU has an inbuilt one.

It is indeed the 4.2 SC

question on mapping. i've somehow got it to match the petrol trims roughly, maybe it could be a tad richer but thats simple enough. but it pulls hard and well throughout the rev range with no misfiring which is great, but theres a very harsh lurch when i take my foot off the throttle, i assume its ...

been driving on petrol for a bit to let the trims settle before i ruin them with lpg.



not quite sure why its all over the place anymore. theres defo the difference between 2 banks. but the difference between 1200-1700 is ridic, from 18% to 5?

It turns V8s into somewhat economical daily runners. My 4.2 SC monster goes from 10mpg, to roughly 20mpg. Providing I buy from my Asda at 56p a litre which I always do. I'd be curious what I'd get on a motorway run as well since that's all city driving.

Plus I don't cherish having to pay fuel duty ...

Supposedly smoke tests don't show this minute leak. Not sure how not but I wanted to be sure. Also seems like made no diff. It's back at 18% for Bank 1 and 10% for Bank 2.

Am outta ideas now tbh. Constant smoke tests, the intake has been reassembled more times than I can remember with fresh gaskets ...

changed the sucker, my trims seem to now be in the 10% region for one bank and 8% for the other.

So defo think it's the pcv pipe since the bit that connects to the throttle housing just before the supercharger is covered in oil , so most likely the leak. Am going to try to replace the orings to see if that'll fix it.

new maf in, the STFT are around 20% with the reset of adaptations so I doubt it was the MAF but at least I can forget about it. Supposedly the vacuum pipe going from PCV to the SC leaks air somehow. We've just had snow, so can't do too much.

BUT

This all started when I was changing the thermostat ...