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veilsideluke

New Member

• Jul 27, 2011

• #1

I have a 1995 M reg P38 4.6v8.

beautiful motor, gas converted, lovely to drive

one day she started idling funny, then wouldnt drive at all on petrol, but fine on gas.

do have a lil gas leak.

been to footloose 4x4 and 4wd services (2 local specialists) neither can diagnose it.

also, transfer box motor and ecu, and a power drain when left stood still and a dead airbag.

iv been charged for diagnosing the transfer box issue, and airbag but they say that it could take hours to diagnose the other probs and run into hundreds before i even start.

any one have experience of these issues? is it worth spending the dollar or shall i just break it?

 

Bison

Active Member

• Jul 27, 2011

• #2

Hi

I had a similar problem.

Have a look at this link to see if there are any similarities.

http://www.landyzone.co.uk/lz/f10/p38-missfires-petrol-but-runs-perfectly-lpg-95643.html

In the end it turned out to be the lower inlet manifold gasket (Valley Gasket) Try squirting some damp start around the inlet manifold gasket when running on petrol. if the engin gets excited then its possible you might be sucking in air.

Hope this helps

Bison

 

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veilsideluke

New Member

• Jul 27, 2011

• #3

U may have just become my best friend

will give that info to the garage tomorrow. Nice one

 

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mrufff

New Member

• Jul 27, 2011

• #4

had same problem but mine is a single point lpg

problem was lambda sensor

 

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veilsideluke

New Member

• Jul 27, 2011

• #5

mrufff said:

had same problem but mine is a single point lpg

problem was lambda sensor

Click to expand...

iv so far changed the plugs, which were about fooked, and the maf which was tested and cleaned.

funny thing was it was sat for 6 weeks, started fine when cold and lasted a couple of mins. then under any revs would just cut out until i took my foot off the throttle. so wasnt driveable.

then after a few more mins, sarted searching then eventualy cuts out

I have an old multipoint system with a manual switchover.

switch it to gas and she runs perfect, well as lumpy as it usually does but not noticeably different to b4.

Now the really funny thing.... Limped it to the specialists on gas only, got the, parked up, decided to try it on petrol.

Hey presto, problem solved. ran it round the block, idled and revved beautifully on fuel.

been left a week now, had a call today, still not running right on petrol. WTF is going on??????

 

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liverpool-luke

New Member

• Jul 27, 2011

• #6

just to put my 2p's worth in, I am a LPG enthusiast with a good back ground in DIY mechanic's and LPG install's I have a large collection of LPG software and currently work in an LPG garage (altho not officially trained) sometimes if a car runs well on gas but not petrol it's because the petrol side isn't working as it should be but when flicked to LPG the lpg has learned how to make the car work with the current fault, when you flick back to petrol the petrol ECU need's time to reset it's self to work correctly, if the problem persist's run the car on petrol for a while then get the LPG system re configured

 

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veilsideluke

New Member

• Jul 27, 2011

• #7

liverpool-luke said:

just to put my 2p's worth in, I am a LPG enthusiast with a good back ground in DIY mechanic's and LPG install's I have a large collection of LPG software and currently work in an LPG garage (altho not officially trained) sometimes if a car runs well on gas but not petrol it's because the petrol side isn't working as it should be but when flicked to LPG the lpg has learned how to make the car work with the current fault, when you flick back to petrol the petrol ECU need's time to reset it's self to work correctly, if the problem persist's run the car on petrol for a while then get the LPG system re configured

Click to expand...

would do that but in this case after anout 5 mins she wont run on fuel at all

 

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liverpool-luke

New Member

• Jul 27, 2011

• #8

veilsideluke said:

would do that but in this case after anout 5 mins she wont run on fuel at all

Click to expand...

then the next step is to disconnect the battery for about 10 mins then re connect and leave on idle for 10 mins the car needs to run perfectly on petrol before you work on the LPG side, if there's a fault with the petrol side the petrol ECU should find it and log the fault in the ECU which can be read by most OBD2 readers if there's a fault with petrol LPG will be worse

 

kooky_guy

Well-Known Member

• Jul 28, 2011

• #9

Are you sure the fuel side is working ok on the petrol?

It could just be the filter is clogged or the fuel pump is shot. It'd be nice to think that the garages would have tested this, but you never know with some of these numpties.

Hard to think what else it could be - doesn't the LPG ECU piggy back off the main engine ECU, so any non fuel faults would also affect the LPG.