Petrol fumes from THP engine

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xantia_v6
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Petrol fumes from THP engine

Unread post by xantia_v6 »

Our 308 CC with the EP6-CDT engine has started to smell of petrol, but it seems to be intermittent. The fumes are raw fuel (not exhaust nor crankcase fumes) and seem to be drawn in through the air conditioning system, usually after idling at traffic lights or similar. Annoyingly it has never happened at home, not has any smell been detected under the bonnet.

I have looked at all the visible fuel lines under the bonnet, and the vapour purge valve, but there is no sign of any leakage. The engine is running perfectly.

The crankcase fumes smell awful, but not of petrol.

I have also checked the connections to the high pressure fuel pump, but there is no leakage at either pipe. It is almost impossible to see the injector fuel rail, maybe it can be seen from underneath with the exhaust pie disconnected, but I have not gone that far yet.

Has anyone heard of any places where these engines leak?

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Re: Petrol fumes from THP engine

Unread post by Peter.N. »

Haven't had a petrol engine for many years so not familiar with modern ones, the only thing I can suggest is that you stop as soon as possible when you get the smell, lift the bonnet and have a good sniff/look.

Peter

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myglaren
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Re: Petrol fumes from THP engine

Unread post by myglaren »

My mate had a Carina II that was perfectly fine until the sunroof was opened, after which the cabin filled with an overwhelming petrol pong.
Never did find out why.

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white exec
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Re: Petrol fumes from THP engine

Unread post by white exec »

The annoying thing about petrol weeps is that they remain pretty much invisible :(
Not much help...

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GiveMeABreak
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Re: Petrol fumes from THP engine

Unread post by GiveMeABreak »

Here are the known areas of petrol leaks. If you can narrow it down to one of the zones I can get a bit more detail. If the smell is coming in more or less as soon as or shortly after the engine is started, then more likely to be a fuel leak and - obviously near the air intake.
308 Petrol A.PNG
ZoneDescription
Zone "A"Filling pipework assembly
Zone "B"Fuel gauge and pump assembly
Zone "C"Fuel tank
Zone "D"Pipework to engine
Zone "E"Canister absorber
Zone "F"Fuel filter

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xantia_v6
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Re: Petrol fumes from THP engine

Unread post by xantia_v6 »

Funny that the official list does not include the high pressure fuel pump or fuel rail, which are the 2 (expensive) components that come up as culprits for the same engine in a Mini.

I will look again at the HPFP. I hope that it is not the fuel rail, this picture shows the fuel rail from above after the manifold has been removed for access.
Image

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Re: Petrol fumes from THP engine

Unread post by GiveMeABreak »

Sorry - I had to go and have just got back after a long afternoon - there is another one for the Engine Circuit - let me know the zone of interest:
308 Petrol B.PNG
[b]Zone[/b]
Description
Zone "A"Timing face
Zone "B"Coupling face
Zone "C"Inlet face

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Re: Petrol fumes from THP engine

Unread post by xantia_v6 »

I have spent some more time on this, and have found that the petrol fumes seem to be coming from the rear or timing end of the engine (zones A and C), but the fumes are only present when the engine is running, not when switched off nor with just to low pressure part of the system pressurised. This is not good news, as the high pressure components are almost inaccessible, and generally expensive.

Marc, can you find me the troubleshooting guides for engine zones A and C?

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Re: Petrol fumes from THP engine

Unread post by GiveMeABreak »

Will do, leave it with me...

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Re: Petrol fumes from THP engine

Unread post by GiveMeABreak »

Finally... :)

There are 2 sections - Leaks by Area (Zones A, B & C) or by known cases in the following table.

Leak Diagnostic by Known Cases
ProbabilityLocating the leakZone
LowFuel supply pipe on high pressure fuel pumpCoupling face - Stage B2
LowHigh pressure fuel supply pipeInlet face - Stage C1
LowPressure sensor on the fuel high-pressure injection railInlet face - Stage C2
LowFuel injectors on the fuel high pressure common injection railInlet face - Stage C3
LowPlug on fuel high pressure common injection railInlet face - Stage C4



Leak Diagnostic by Area

Zone A - Timing Face
Zone A Timing Face.PNG

A1: Fuel Connection Towards Adaptor
Locating the LeakInformation
Zone A Timing Face.PNG
Sealing: Hoses force-crimped on click-fit unions

Probability: Low

Possible causes:
  • Incorrect crimping of the hoses
  • Damage to the click-fit unions
Access: Easy

Repair: Replace the fuel pipes

Zone B - Coupling Face
Zone B Coupling Face.PNG
Stage B1: Canister pipe on air inlet
Locating the LeakInformation
Zone B1 Cannister Pipe Air Outlet.PNG
Zone B1 Cannister Pipe Air Outlet.PNG (154.55 KiB) Viewed 96 times
Sealing:
  • 2 O-ring seals
  • Pipe force-crimped on click-fit union
Probability: Low

Possible causes:
  • Incorrect positioning of the fastener
  • Seals sealing fault
  • Absence of seal
  • Incorrect crimping of the pipe
  • Damage to the click-fit union
Access: Average
Repair: Replace the canister pipe on the induction
Stage B2: Fuel supply pipe on high pressure fuel pump
Locating the LeakInformation
Zone B Fuel supply pipe High Pressure Fuel Pump.PNG
Zone B Fuel supply pipe High Pressure Fuel Pump.PNG (157.7 KiB) Viewed 96 times
Sealing:
  • 2 O-ring seals
  • Hose force-crimped on click-fit union
Probability: Low

Possible causes:
  • Incorrect positioning of the fastener
  • Seals sealing fault
  • Absence of seal
  • Incorrect crimping of the hose
  • Damage to the click-fit union
Access: Average

Repair: Replace the damaged low pressure fuel piping

Stage B3: High pressure fuel pipe on fuel pump
Locating the LeakInformation
Zone B High pressure Fuel Pipe  Fuel Pump.PNG
Zone B High pressure Fuel Pipe Fuel Pump.PNG (156.15 KiB) Viewed 96 times
Sealing: High pressure pipe distorted against the cone on the pump

Probability: Low

Possible causes: Incorrect tightening of the nut

Access: Average

Repair: Replace the high pressure pipe

Zone C - Inlet Face
Zone C Inlet Face.PNG
Inlet face - Injection system.

Stage C1: High pressure fuel supply pipe
Locating the LeakInformation
Stage C1 High Pressure Fuel Supply Pipe.PNG
Stage C1 High Pressure Fuel Supply Pipe.PNG (156.69 KiB) Viewed 96 times
Sealing: High pressure pipe distorted against the cone on the rail

Probability: Low

Possible causes: Incorrect tightening of the nut

Access: Average

Repair: Replace the high pressure pipe
Stage C2: Pressure sensor on the fuel high-pressure injection rail
Locating the LeakInformation
Stage C2 Pressure sensor on Fuel High Pressure Injection Rail.PNG
Stage C2 Pressure sensor on Fuel High Pressure Injection Rail.PNG (163.94 KiB) Viewed 96 times
Sealing: Cone shape of the sensor tight against the rail

Probability: Low

Possible causes:
  • Sensor incorrectly tightened
  • Fault with the contact surfaces
Access: Difficult

Repair: Replace the pressure sensor on the rail

Stage C3: Fuel injectors on the fuel high pressure common injection rail
Locating the LeakInformation
Stage C3 Fuel Injectors on Fuel High Pressure Common Injection Rail.PNG
Stage C3 Fuel Injectors on Fuel High Pressure Common Injection Rail.PNG (153.25 KiB) Viewed 96 times
Sealing:
  • Detachable O-ring seal
Probability: Low

Possible causes:
  • Incorrect positioning of the fastener
  • Gasket sealing fault
  • Absence of seal
Access: Difficult

Repair:
  • Replace the 3 seals and the injector clip
  • Check the tightening torque of the plug on the fuel high pressure common injection rail

Stage C4: Plug on fuel high pressure common injection rail
Locating the LeakInformation
Stage C4 Plug on Fuel High Pressure Common Injection Rail.PNG
Stage C4 Plug on Fuel High Pressure Common Injection Rail.PNG (144.55 KiB) Viewed 96 times
Sealing: Force-fitted plug

Probability: Low

Possible causes: Incorrect positioning of the plug

Access: Difficult

Repair:
  • Check the tightening torque of the plug on the fuel high pressure common injection rail
  • Replace the plug on the fuel high pressure common injection rail

Inlet face: Fuel vapour recirculation circuit

Stage C5: Fuel vapour recirculation pipe on canister purge electrovalve
Locating the LeakInformation
Stage C5 Fuel Vapour Recirculation Pipe on Canister Purge Electrovalve.PNG
Stage C5 Fuel Vapour Recirculation Pipe on Canister Purge Electrovalve.PNG (148.95 KiB) Viewed 96 times
Sealing:
  • 2 O-ring seals
  • 1 Clip
  • Pipe force-crimped on click-fit union
Probability: Low

Possible causes:
  • Incorrect positioning of the fastener
  • Seals sealing fault
  • Absence of seal
  • Incorrect crimping of the pipe
  • Damage to the click-fit union
Access: Difficult

Repair: Replace the fuel vapours recirculation pipe
Stage C6: Fuel vapour resuction pipes on canister purge electrovalve
Locating the LeakInformation
Stage C6 Fuel Vapour Resuction Pipes on Canister Purge Electrovalve.PNG
Stage C6 Fuel Vapour Resuction Pipes on Canister Purge Electrovalve.PNG (157.74 KiB) Viewed 96 times
Sealing: Pipes force-fitted

Probability: Low

Possible causes: Incorrect fitting of the pipe

Access: Average

Repair: Replace the canister pipes
Stage C7: Fuel vapour hose on air inlet manifold
Locating the LeakInformation
Stage C7 Fuel Vapour Hose on Air Inlet Manifold.PNG
Stage C7 Fuel Vapour Hose on Air Inlet Manifold.PNG (170.29 KiB) Viewed 96 times
Sealing:
  • 2 O-rings in the click on union
Probability: Low

Possible causes:
  • Fault with the seals
  • Absence of seal
  • Incorrect fitting of the pipe
  • Damage to the click-fit union
Access: Average

Repair: Replace the electrovalve

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Re: Petrol fumes from THP engine

Unread post by xantia_v6 »

Thanks Marc, that gives me a few ideas for things to check. I am still trying to establish a pattern of when the petrol smell occurs. It seems that it is not present when the engine is cold, nor to any great extent when the car is stationary. This makes tracing a bit difficult as the engine must be cold and partially dimantled to get to a number of the relevant components.

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Re: Petrol fumes from THP engine

Unread post by GiveMeABreak »

No problem, I do hope it is in an accessible area Mike.

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Re: Petrol fumes from THP engine

Unread post by xantia_v6 »

No luck yet isolating the source of the fumes. I did go as far as removing the inlet manifold to check the fuel rail and other hoses down there, but no sign of a leak.

I am now suspecting that the leak might actually be the A/C evaporator. The A/C is still functioning well. but we seem to only smell the fumes when the refridgeration is turned on (and the evaporator cold).

Out of curiosity, I tried to find the part number of the evaporator, but it seems that it is not listed as a separate part (you have to buy the complete heater housing), and it is not clear whether they are are available after-market (as there is no part number to search on).

I will visit a local A/C specialist who should have a gas leak detector.

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Re: Petrol fumes from THP engine

Unread post by white exec »

UV tracer dye for AC, Mike - something that could be left in, and which you could detect yourself, if the sniffer doesn't find anything.

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Re: Petrol fumes from THP engine

Unread post by xantia_v6 »

Yes, but dye is not much help for a leak in the evaporator... I have checked all the A/C plumbing under the bonnet and nothing is oily. Having looked some more, it seems that sourcing an evaporator at a reasonable price for a 308 is a real issue, as none of the usual vendors list them.