Range Rover Sport 4.2 LPG mechanic

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mgrover
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Range Rover Sport 4.2 LPG mechanic

#1 Post by mgrover » Mon Dec 20, 2021 5:16 pm

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 like someone to fix the petrol and then tune the LPG to perfection because am generally just sick of messing around with it. Or for now, just anyone that'll fix the petrol since thats it's own issue.

It's already had its heads rebuilt with hardened valve seats.

Ideally someone near Leeds, any suggestions please?

Cheers
Martin

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Re: Range Rover Sport 4.2 LPG mechanic

#2 Post by Brian_H » Mon Dec 20, 2021 5:19 pm

Simon - LPGC on this forum is probabbly your best bet and in the right area. He is in South Elmsall near Doncaster.

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Re: Range Rover Sport 4.2 LPG mechanic

#3 Post by LPGC » Mon Dec 20, 2021 7:47 pm

If you have a fault condition on the 4.2 SC Jag / Rangerover engine, when you clear it the fuel trims can act strangely at first but should settle down when IM readiness has cleared.

I'd advise clearing any error codes, then start the engine and don't hang around letting it idle, immediately set off and go for a bit of a drive on petrol. If no fault codes appear turn it off and let it cool down overnight, go for another drive the next day from a cold start... Then check fuel trims.

If fuel trims have been incorrectly learned you can clear them by causing a hard error, such as multiple cylinder misfires along with disconnected petrol injector errors by disconnecting one of the injector harness connectors at the rear end of the plenum (one per bank) which will do the necessary by causing the problem on 4 cylinders.

Fuel trims of 10% aren't unusual anyway... But how much in excess?

The problem here is I'm so busy.
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mgrover
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Re: Range Rover Sport 4.2 LPG mechanic

#4 Post by mgrover » Mon Dec 20, 2021 8:50 pm

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 be thrown.

Either way, I've had enough of trying to figure this out.

It's been 2 years and no real luck.

The only "stability" I've had, is just mapping the LPG to be richer to keep the system happy but now I'd rather just get the petrols adaptive fuel trims completely fixed first.

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Re: Range Rover Sport 4.2 LPG mechanic

#5 Post by LPGC » Tue Dec 21, 2021 9:25 am

Have you got the correct spec wide band lambda probes fitted?
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Re: Range Rover Sport 4.2 LPG mechanic

#6 Post by mgrover » Tue Dec 21, 2021 11:22 am

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.

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Re: Range Rover Sport 4.2 LPG mechanic

#7 Post by LPGC » Fri Dec 24, 2021 1:12 am

Yes I did mean pre-cat.

Have you tried what I suggested yet (clear error codes, reset adaptions, only run on petrol - set off for a drive immediately, etc)?
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mgrover
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Re: Range Rover Sport 4.2 LPG mechanic

#8 Post by mgrover » Fri Dec 24, 2021 9:04 am

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

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Re: Range Rover Sport 4.2 LPG mechanic

#9 Post by LPGC » Fri Dec 24, 2021 7:54 pm

What are the fuel trims like now? Are you still getting error codes on petrol?

If you're not getting error codes now you can move on to setting up the LPG system properly.
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Re: Range Rover Sport 4.2 LPG mechanic

#10 Post by mgrover » Sat Dec 25, 2021 9:43 am

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

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Re: Range Rover Sport 4.2 LPG mechanic

#11 Post by mgrover » Sat Jan 01, 2022 4:41 pm

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

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

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Re: Range Rover Sport 4.2 LPG mechanic

#12 Post by LPGC » Sat Jan 01, 2022 4:50 pm

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?
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mgrover
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Re: Range Rover Sport 4.2 LPG mechanic

#13 Post by mgrover » Sat Jan 01, 2022 5:01 pm

LPGC wrote:
Sat Jan 01, 2022 4:50 pm
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 leak, all the way back since late 2020. like a puddle but didn't put two and two together till yayday.

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