Hello again everybody,

I have a niggling issue with my '85 HE - on light to medium throttle while cruising with the windows down the car is magic. When really giving it a bootful though, for more than a couple of seconds (ie up a hill), the car is truly amazing, except I get a big whiff of petrol vapour. Has anybody here experienced something similar? It's not coming from the fuel tank (well, that is my assumption), and is much less noticeable with windows up, so I'm pretty sure it's an under bonnet issues.

Obviously by the time I pull up and open the bonnet there is nothing to see or smell, and I'm just a bit mystified as to why this is happening. It's pretty hard to replicate in the garage too, as I can't wind the throttle right up for any length of time without revving the living hell out of the thing. I'm happy to start wrapping tissues around fuel hoses and connectors and doing some test drives, but would appreciate any advice on where to target my search!

Dave

 

the pump maintains a specific pressure and the regulator up front just regulates what the rail gets, so driving faster or more isn't going to affect the fuel pressure. If its the smell of raw fuel it may be more related to heat/pressure causing vapors to escape from the tank or charcoal canister.

Definitely check your injectors and lines, but I wouldn't go stuffing paper towels in your engine bay. I had to pull the old "drill a hole in the gas cap" because my charcoal canister gave up and was dumping fumes/my tank was overpressurizing. Now I rarely notice any smell

 

Sounds to me like fuel vapour blowing back through the air filter box/manifold/head gasket join. Are you 100% sure the manifold nuts are tight, they do loosen quite often, and that the air filter covers are properly seated and sealed?

greg

 

Adding to the above.

The charcoal cannister is tucked up under the LH headlight, in front of the LH front wheel. Remove that plastic panel CAREFULLY to reveal it and its myriad of hoses.

I reckon the cannister is way past its use by date and the hoses also.

Fumes under the driving conditions you mention are with minimal vacuam that draws the fumes into the engine for reburn. That allows the fumes from that cannister to escape to the atmosphere and your nostrils.

Obviously there may be other gremlins at play here, but that cannister is the main item I have dealt with outside the tank itself and damaged pipes/hoses under the car.

The XJ-S is fickle with odours, and what you believe to be from the front is not always fact.

There are fuel hoses up on top of the rear cradle (one on each side) that will be very SAD by now, they are easier to "feel" than "see", so check them also.

The list continues...................