4.2 SC LOTS of white smoke...

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Rawlplug

Member
Posts
35
Location
Devon
Hello all, new to the forum and new to Range Rovers. We bought an 05 4.2 SC with LPG last week - what an awesome machine, well, that is to say it was an awesome machine. Sequence of events as follows:

- check engine light came up: lean on both banks, figured it was because of the LPG, cleared the codes
- took the engine cover off to make sure no pipes were off and letting in unmetered air, all seemed fine
- the following morning went to work, all OK
- started her up to drive home that evening and MASSES of dense white smoke out the back. No funny noises or loss in performance. When warmed up and the LPG kicked in all seemed fine, no smoke.
- checked under bonnet at home to find I'd forgotten to put the oil cap back on, did this and started up again: loads of white smoke again, smoke smells of petrol
- oil seems normal, no mayonnaise, coolant level unchanged
- booked her in to a local indy, which will be in a few weeks, was advised to try an injector cleaner in the meantime

I'm a bit reticent to start her again without a bit of a plan. Any thoughts? As it seems fine on LPG I'm hoping it's just an overfueling issue. Any obvious things I should check?
Thanks all! Here's hoping this isn't a taste of things to come...
 
Lpg on a Jag v8 is a recipe for disaster the valve seats can't take the higher combustion temps.
running it lean will do no good to it.
get her on diagnostics.
 
Contact seller as its new to you could be why it was up for sale deffo if it came from a dealer throw it back at them could be an expensive fix.
 
Henry_b said:
Lpg on a Jag v8 is a recipe for disaster the valve seats can't take the higher combustion temps.
running it lean will do no good to it.
get her on diagnostics.
Click to expand...

Aaaghhh! Don't say that! It's got flashlube if that makes any difference?
Agree re diagnostics.
 
CEL is on. first off you need to see the codes to see what threw the CEL on. personally you want to be careful running it you could well damage the cats or the o2 sensors until you know what set it off. im wondering if the oil cap being off caused an issue with crankcase pressure and oil being pushed through, but that would be more from over pressure than underpressure. but no exhaust smoke when on LPG ?

it is smoke, or steam ?
 
Codes were P0171 and P0174 which came up before the smoke started. I cleared them and they have returned since as pending codes only. If you really floor it when the LPG is on it will cut back to petrol, so I'm guessing the LPG cant keep up, hence running lean?
The smoke does seem smokey and does smell of petrol. Coolant level is unchanged.
 
Definitely sounds like air-leak somewhere. You should re-check all the intake system, and probably where the LPG injectors are fitted ? Are these properly sealed on the manifold ?
 
i'm thinking with the P0171 /P0174 code and with the white smoke this is a crankcase pressure issue. why on petrol, not on LPG I don't know.

have you done a crankcase pressure test ? did this happen when the oil cap was off only ?

 
The codes came up without me touching the engine. The smoke started after I'd taken the cover off, had a look round and forgotten to put the oil cap on. I put the oil cap back on and it was still smoking - though I turned the engine off straight away. Perhaps it needs to be run a bit for residual fuel to be burnt now that the cap is back on??
 
Rawlplug said:
The codes came up without me touching the engine. The smoke started after I'd taken the cover off, had a look round and forgotten to put the oil cap on. I put the oil cap back on and it was still smoking - though I turned the engine off straight away. Perhaps it needs to be run a bit for residual fuel to be burnt now that the cap is back on??
Click to expand...


ok. you're talking the engine top cover that has two 10mm bolts that sit under the scuttle panel and you have to take the oil filler off to get the cover out ?
why did you take the cover off ? just having a look at belts ect or a specific reason (note, I just got a 4.2SC too and working through things not happy with - see my thread on 4.2 SC niggles and needs)

under that cover, as you know sits the intake for forced induction. and the big arsed clips that hold it in place are after the MAF. if they are not tight, then the intake will suck in unmetered air and a lean burn will occur as the engine is reading the air going in through the filter and not metering the air being sucked in after the MAF. and you'll get a lean burn.

white smoke is often the case when the crankcase pressure is too high, forcing oil through to the combustion chamber. with the oil cap off, your crankcase pressure would be reduced.. but a stuck CCV would result in PO171 / P0174 and white smoke. it fits ! maybe the CCV was weak and running it with the oil cap off has hastened its failure... try the oil cap test per the video
 
Rawlplug said:
Hello all, new to the forum and new to Range Rovers. We bought an 05 4.2 SC with LPG last week - what an awesome machine, well, that is to say it was an awesome machine. Sequence of events as follows:

- check engine light came up: lean on both banks, figured it was because of the LPG, cleared the codes
- took the engine cover off to make sure no pipes were off and letting in unmetered air, all seemed fine
- the following morning went to work, all OK
- started her up to drive home that evening and MASSES of dense white smoke out the back. No funny noises or loss in performance. When warmed up and the LPG kicked in all seemed fine, no smoke.
- checked under bonnet at home to find I'd forgotten to put the oil cap back on, did this and started up again: loads of white smoke again, smoke smells of petrol
- oil seems normal, no mayonnaise, coolant level unchanged
- booked her in to a local indy, which will be in a few weeks, was advised to try an injector cleaner in the meantime

I'm a bit reticent to start her again without a bit of a plan. Any thoughts? As it seems fine on LPG I'm hoping it's just an overfueling issue. Any obvious things I should check?
Thanks all! Here's hoping this isn't a taste of things to come...
Click to expand...
V8's seem to be notorious for head gasket failure which would probably give the symptoms. This is a DIY repair, but it's a lot of work. There are some good YouTube videos showing the process if this is the case....
 
Rawlplug said:
Aaaghhh! Don't say that! It's got flashlube if that makes any difference?
Agree re diagnostics.
Click to expand...

It does but I didn't dare risk it on my Jag.

The Jag engine is sublime. Bit of an issue with tensioners on earlier models but we'll before yours. Seem to remember some pipe in the v giving issues but maybe I am mixing that up with something else.
 
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