Fuel smells

02 - Fuel & Emissions
With the fuel tank in the front of the car, DeLorean owners have much more opportunity to experience the smell of gasoline than owners of more conventional vehicles with the tank in the rear.  The filler cap is right in front of the steering wheel, so the driver is immediately notified if there is any spillage at fill up.  The same sensation will be the first indication of a worn gas cap seal, cracked hoses or loose clamps at any of the connections at the tank. A damaged hose connected to the roll-over valve, or a damaged roll-over valve itself, can also be the culprit.
 
Fumes coming from the pump seal are most often a poorly seated pump and boot that have been floated loose of the tank by a rising fuel level at fill up.  This condition often leads to fuel running onto the ground beneath the car and owner panic.  Other problems can be a torn or shrunken fuel pump cover seal, loose high pressure connection filling the boot with fuel, and a torn or otherwise damaged fuel pump sealing ring (boot) itself.
 
A more obscure failure is the obstruction of the rollover valve P/N  101402. If this valve becomes obstructed, as the tank heats up the fuel vapors will not be vented to the tank, but will be forced out either at the fuel pump or from the filler cap, both of which are close to the cabin air intake. A clue on this failure is a noticeable "hiss" as you remove the gas cap after driving the car.
 
Fumes entering the cabin have sparked some desperate measures from imaginative mechanics.  The most harmful is to block the fresh air manifold drain, trying to keep the smell out.  This will allow the manifold to fill up in a heavy rain and flood the passenger's foot well through the cabin fan mounting.
 
The rigid fuel lines seldom give any problem, but the flexible connectors wear out and leak.  The most likely one is the high pressure feed to the fuel accumulator.  A gas smell accompanied by poor running and fuel on the ground gives this problem away.  Fuel connection and lines in the engine bay are subject to cracking, especially at the banjo fittings.  The copper sealing washers can break or allow a leak at a scored place.  The brass hollow bolts have been known to break.  All of these are accompanied by a smell and that is often the first indication of a problem.
 
With the advent of fuel vapor control in the 80s, a carbon canister was introduced that can be a source of gas smell.  If the canister is old, or plugged, or has gotten wet, it will stink of gasoline.  This is not as apparent a problem in a DeLorean, because the canister is contained in the left rear pontoon and vents to the atmosphere out the bottom.  In the opposite of the original problem, the driver is unlikely to be bothered by fumes that don't go past his nose.  In conventional cars, the canister is in the front engine bay and fumes from it are easily detected.
 
In conclusion, a fuel smell always warrants an immediate inspection.

By Warren Wallingford with edits by James Espey, DeLorean Motor Company (Texas)
Article ID: 42, , Modified: 8/14/2016 at 4:21 PM

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