Re: [DML] Fuel Pump or Not Fuel Pump?

[Mike Substelny <msubstel@xxxxxxxxxxxxx>]

Marv Hien wrote:

> Went to start the car today.  It fired up and stalled
> about 3 seconds later.  Engine now turns over strongly
> but does not fire.  

> Removed the air filter and dropped a few drops of gas
> into what would have been the carburetor in an older
> car (I'm not a mechanic but it seemed fuel mixed with
> air here might do something).  Engine started immediately
> and ran a few turns until that gas was exhausted... a 
> second or so.  So I seem to have ignition capabilities
> but no fuel where it is needed.


I suggest you start with the simple.  I believe the number one most 
failure-prone component in DeLoreans is the original fuel tank sender 
unit (though others disagree with me).  In the past I have seen symptoms 
exactly like yours in several DeLoreans, and it has always turned out to 
be either an empty gas tank or a fuel inlet sucking air in a partially 
empty gas tank.  In either case, you should be able to add a gallon of 
gas to the tank and get it started.

I think the out-of-gas failure happens to DeLoreans more often than most 
other cars simply because drivers of our generation is accustomed to 
reliable fuel gauges.

The half-empty failure happens to DeLoreans because the fuel inlet line 
can develop cracks, causing gas to be sucked in from the middle of the 
tank instead of the bottom.  This is more a factor of age than miles, so 
it would not be surprising in your 23 year old, 11K mile car.  It can 
also happen if the fuel inlet becomes disconnected from the bottom of 
the tank and starts wandering around in there, but I think that is 
usually cased by clumsy repairs rather than age.  If no one has been 
screwing around in your gas tank, then the cracked fuel inlet hose is 
more likely.

I'm not promising that your fuel pump is good.  But in my experience the 
fuel pump is super reliable while the fuel gauge sender and inlet hose 
are not so reliable.  If your DeLorean only has 11K miles on the clock, 
I bet your fuel pump is still strong.   The test suggested by David 
Teitelbaum can help diagnose a bad fuel pump.  FYI if you turn the 
ignition key to "RUN" (not start) in a quiet environment you should be 
able to hear the fuel pump hum for a couple of seconds.  That hum, or 
lack thereof, tells you a lot.

Make sure the car is on a level surface, add a gallon of gas, and I bet 
she fires right up.

Good luck, Marv,

- Mike Substelny
VIN 01280, 11 years





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