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Joined: Aug 17 2020
Posts: 10

hello my name is luke,have had a 2000 p38 4.6 vogue for around 2 years now and its been great until a week or so ago.
i am after some some guidance/advice and all of you guys seem very knowledgable so thought id ask here as i'm at a bit of a loss.
around a week ago i was pulling out of the turning to my road when i heard a pop not unlike a relay blowing with a loss of power and misfiring.
i put it on a snapon verdict 7 code reader which stated multiple misfires.
to date i have replaced:plugs,coil packs,maf sensor,cats and lambda sensors with no appreciable effect.

the car does start and move but with no throttle response or power whatsoever,the only code i now have is rough road signal implausable.
i believe this is something to do with the abs?if so can this effect the engine and give the symptoms above. as said i am at a bit of a loss at where to look next.any advice /guidance you could give would be much appreciated

thanks for your time

luke

Member
Joined: Dec 30 2015
Posts: 2004

Hi Luke and welcome. :)

I think you probably need to get a P38 code reader on there and pull the codes again. Where are you in the country? There's probably someone nearby with a nanocom.

Member
Joined: Aug 17 2020
Posts: 10

hi
thanks for the welcome,cant wait to get more involved with the forum.
i do have the use of snap on verdict 7 and icarsoft lr2 code readers but if the nanocom is better and someone would be willing to help i'd be more than happy to compensate them.
i am based in thurrock essex

thanks

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Joined: Dec 30 2015
Posts: 4921

Most generic readers will work for engine codes, particularly on the Thor, as it is fully OBD2 compliant so I doubt a Nanocom will give anything that the others won't..

The pop wasn't a spit back though the inlet by any chance? Have you got any air leaks between MAF and throttle body?

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Joined: Jun 24 2020
Posts: 12

Welcome to the forum Luke.
Do you have an LPG system installed?
Is it still popping when the engine is running?

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Joined: Aug 16 2020
Posts: 6

G'day Luke & welcome.

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Joined: Mar 22 2016
Posts: 1213

Have you checked the TPS, they can make it pop, fart, not respond to throttle..

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Joined: Sep 02 2016
Posts: 507

Crank Position Sensor on its way out ?

Member
Joined: Aug 17 2020
Posts: 10

hi guys, thanks for all the welcomes.

to answer a few of the above questions
there are no air leaks between the maf and throttle body
it doesnt pop while the engine is running and there is no lpg system fitted.
will check the throttle position and crank sensors,if someone could point out how to do this it would be great.

have changed the plug leads today and rescanned it using icarsoft lr2 scanner

it now shows the following codes

1:rough road signal implausable
2:emissions relevent misfire multiple cylinders
3:emissions relevent misfire cyl 8
4:catalyst damaging misfire multiple cylinders
5:catalyst damaging misfire cylinder 8
6:misfire with low/empty fuel

any further help or advice anyone could offer would be of great help and much appreciated

thanks

luke

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Joined: Jun 17 2018
Posts: 716

Check fuel pressure at the rail.

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Joined: Jan 16 2017
Posts: 767

Might be an idea to pull the spark plug from cylinder 8 to see if its giving any clues as to whats wrong there (compare to others and see if any deposits on it look different). If you have the tools to do it, a compression test would also be an idea, though if its suddenly started happening I wouldn't expect that to show anything.

The one thing you haven't mentioned changing are the HT leads - are these new and missed from the list, or are you still using the same leads?

Member
Joined: Aug 07 2019
Posts: 193

maybe the reluctor ring on the flex plate has a tooth out of place or similar and the CPS has been damaged . their was a similar problem like this not long ago, just remove the cover (front of gearbox ) and have a look with a torch

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Joined: Dec 30 2015
Posts: 4921

He can't, he's got a Thor which doesn't have the inspection plate like on the GEMS, it's an integral part of the cast alloy sump.

Interesting that the main codes are for number 8 but changing plug leads and plugs hasn't cured it and if it was a coil it would affect 2 cylinders and not just the one. Is it a misfire like just one cylinder not firing (lumpy idle, but smoothing out once the revs increase) or general rough running?

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Joined: Aug 17 2020
Posts: 10

hi chaps

little update,as suggested above i have just checked the pressure at the fuel rail it is 20psi with the ignition on and 49psi with the engine started and idling
does this sound right?

thanks again for your help

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Joined: Dec 30 2015
Posts: 4921

That sounds fine, as long as it maintains that pressure when you rev it.

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Joined: May 14 2020
Posts: 53

Are the plugs leads properly pushed in ---- had that on mine ---- funny that was#8 ---- if it's lumpy idle that smooths out then must be plug/lead or firing order of leads incorrect

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Joined: Aug 17 2020
Posts: 10

hi chaps.

quick question,would getting the adaptive values reset help any?if so what should the values be.

thanks

luke

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Joined: Jan 16 2017
Posts: 767

The reset should reset them to the factory defaults, which it should then learn from over a short period of driving. You don't need to enter them. Its worth a shot if you have access to do it, but should fix itself at the same time.

Did you remove and check the plug on cylinder 8 to see what sort of state its in? Sooty or otherwise may tell us whats going on since it seems to mainly mention that cylinder. May also be worth checking the one its paired with (5) just in case something there is causing issues on the other side of the same coil (reduced gap or similar?).

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Joined: Aug 17 2020
Posts: 10

hi again chaps could any tell me how to post pics please.
have some of the spark plugs to post up.

thanks
luke

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Joined: Dec 30 2015
Posts: 4921

https://rangerovers.pub/topic/1877-how-to-topic