16 replies to this topic

[Bunji81]

So….. after a not too spirited drive (but in no way sedate)…. There was a strong smell of fuel in the cabin….. does anyone have any thoughts or should this be expected from a hot engine that’s 12 inches away from your face??

 

cheers in advance

 

 Bunji 

[sonscar]

Is it fuel or is it exhaust?my wife always says she can smell fuel when it actually is exhaust.
I would not expect any fuel smell from an injected car.If there are any leaks they may well be at high pressure(3 bar ish)Have a look for wet hoses,Steve..

[Quinlan minor]

There shouldn't be any fuel smell inside, or outside, from an MPi.

Check the boot to see if the smell is coming from there, as a starting point. It's, possibly, the likely suspect after enthusiastic bend swinging.

If not, and it's coming from under the bonnet, it needs to be resolved immediately. Fuel leaking under high pressure and a hot exhaust may have catastrophic consequences.

[Steve220]

Check the state of your fuel lines in the boot. Mine split when I first had the car.

[Midas Mk1]

jI split my MPi tank with the nsr shock bottoming out over a pothole, punching the top the tank. Rare to see but check the boot area for any signs of a leak, no matter how small.

The youtube vid did quite well of it 😂

[brivinci]

As stated, look in the boot. There are smaller and not fragile breather system on top of the tank. Mine had cracked at one point. Notice any dip in fuel eco, indicating a leak? Leaks on a high pressure systems usually dont dribble and I would think you would know if you have one pretty quick.

[Bunji81]

Thanks all for the info…. I have had the intake off while fitting an LCB, but made sure not to disconnect any of the fuel rail. I’ll double check everything again as you’ve all mentioned. Part of me thought I may be a dodgy lambda sensor as I had to reuse the original off the cast manifold…. 
 

[brivinci]

You need to determine if this is straight petrol (coming from a leak) or a car running rich. Both are not ideal but one is much more serious! As you just fitted an LCB, ensure it is sealed well everywhere. Exhaust leaking straight from the header will find its way into your nose inside the car. When the car is cold, start it and quickly move some light fabric near the joints and see if it flutters before the exhaust gets hot...or any other means of checking for leaks that you like. 

 

Just to be safe, keep an extinguisher around until you have determined its NOT actual petrol leaking out.

[Bunji81]

You need to determine if this is straight petrol (coming from a leak) or a car running rich. Both are not ideal but one is much more serious! As you just fitted an LCB, ensure it is sealed well everywhere. Exhaust leaking straight from the header will find its way into your nose inside the car. When the car is cold, start it and quickly move some light fabric near the joints and see if it flutters before the exhaust gets hot...or any other means of checking for leaks that you like. 

 

Just to be safe, keep an extinguisher around until you have determined its NOT actual petrol leaking out.

Thanks all for the advice….. on inspection at cold and then hot….. I think, it’s running rich as it only seems to come when the engine is hot. The fresh maniflow exhaust tip seems pretty ‘coked up’ too…

 

is the likeliest culprit the reused lambda sensor??

[brivinci]

Best bet is to run some diagnostics on the motor. Could be a lambda, or stuck in "limp home mode", or a few other issues. You can now download the software free and either buy or build the correct plug to connect to the ECU. Might be worth having a poke around this forum as there plenty of "SPi Running Rich" post with lots of great information.

One thing I would avoid is to just start chucking new parts at it. Better to invest a little money on the cable to connect to your computer, scan the car and then start making more educated next steps.

[Bunji81]

Best bet is to run some diagnostics on the motor. Could be a lambda, or stuck in "limp home mode", or a few other issues. You can now download the software free and either buy or build the correct plug to connect to the ECU. Might be worth having a poke around this forum as there plenty of "SPi Running Rich" post with lots of great information.

One thing I would avoid is to just start chucking new parts at it. Better to invest a little money on the cable to connect to your computer, scan the car and then start making more educated next steps.

Cheers for the advice… much appreciated ;)

[Deeppockets]

Did you find the source of the fuel smell.  I also have a smelly MPI, no sign of petrol leaking from tank or lines.

 

Pretty sure it is originating from the boot. I have had the tank out since and all the breather pipework seems alright. I also replaced the tank filler seals without success of stemming the smell.

 

Thinking about rigging up a low pressure test using an old bicycle tube/valve over the filler cap to force air into the system.

 

Does the carbon cannister go bad? Could it need replacing?

[Deeppockets]

To share my finding over the weekend chasing down the source of the fumes.

 

The carbon cannister and pipe are clear - able to blow down the pipes without issue. The issue seems to be the roll-over valve (part of WFU100560) which seems to present reasonable resistance to air flow when vertical.

 

in summary:

• vertical forward flow (tank to cannister) - resistive
• non-vertical forward flow - blocked
• vertical reverse flow - good

 

Is there any experience with what "good" looks like for this valve? If the breather is being inhibited by the valve then the fumes will be finding another out.

 

On quick research I haven't been able to identify an alternate rollover valve direct replacement. I will keep looking.

[Pablov]

hello, my mpi had a problem with the smell of gasoline in the passenger compartment. It turned out to be the Aston-type plug, which did not allow the inner plug to seal tightly. I checked it by applying Vaseline to the rubber of the inner plug and seeing if it left running when removed and put it.Ahy discovered the source of the smell

[Deeppockets]

Thanks, while I have the original fuel cap I do not think it is sealing well.  I will source a new cap seal and see before delving into more complicated stuff.