Alfa Romeo Repair: fuel pump relay, fuel pump relay, nuisance problem


Question
I own a 1987 Alfa Graduate.  After I purchased this car a month ago, I noticed that the fuel pump kept running after the car is turned off.  I traced the problem to the starter relay behind the passenger seat.  The relay hums when the car is driven, which I do not think it is suppose to do.  To get the pump to stop after turning off the ignition, I just give the relay a little flick.  I opened it up to discover that the silver points melt and pit, thus holding the spring action closed after the relay coil is deenergized.  I have checked all the grounds from this relay, replaced the ignition switch, made the wiring to these units as it should be according to the wiring diagram (previous owners had some wires jumpered)and replaced the relay itself with a new one.  The new one hums lounder than the old one.  Also, when I turn the car off, the motor stays running for about 5-8 seconds before the relay kicks off.
The battery is new and the alternator charges at about 13 to 13.2 volts.  I checked the running voltage at the battery and at the hot terminals on fender in the motor compartment.  Have you ever come across this sort of problem?  I presently run the car on the old relay since I do not want to ruin the new one.  The car runs great except for this little nuisance problem.

Answer
Joe,

Sorry for the delay and there may be a little more, but first let me say that I think you have either a ground problem, or the master relay is bad.  
There are two relays behind the passenger's seat.  One larger than the other.  The smaller one, should be the one you replaced and it controls the fuel pump.  The larger one controls the smaller one.  If it's bad, then it might be causing the problem.
The L-Jet Spiders have a common problem with an internal ground in the ECU.  It fails at the circuit board.  The fix, is to ground it externally.
You mentioned some jumpers that the previous owner or someone had installed.  That may have been one if them.  It's common practice and even the factory techs did it.  My problem right now, is that I don't remember which pin number it is.  I believe it's pin #5, but if I'm wrong, you could cause damage to the ECU.  
The only wiring diagram I have for the L-Jet cars is in Steve's motorhome that we pull the race car with.  Steve and the motorhome are in Key West until Saturday night.  I have notes in the book that will tell me what I can't seem to remember sitting here.
What happens, is the ground is faulty and it allows a small voltage to get past the larger relay from the alternator to the fuel pump relay and the engine will keep running for a few seconds after the key is turned off and until the field voltage drops off.  Also, if that large relay is bad the same thing can happen.  It also reduces the voltage to the fuel pump relay while running and changes it into a buzzer instead of making and holding contact.  Alfa, recommended a external ground and also a jumper between the two relays.
If you want to play with it and check with an ohm meter, to see if pin #5 is grounded with the key off, you can.  You can take the wire connector to the ECU apart and you will see where the wires go in, the housing is numbered with pin numbers.  What they did, was find that wire and splice into the harness and run a ground to the floorboard or even the ECU mount bolts.  L-jet spiders had lots of fuel pump problems.  There are two, you know?  One in the tank and one under the car.  The original cars in the early 80's had an "Inertia Switch" that would pop and shut off fuel in an accident.  It was mounted under the hood.  The fuel pump wire goes from behind the seat, to the submersible pump in the tank, then back to behind the seat, then forward to the passengers side of the firewall, across the front to the driver's side, through the firewall to where the Inertia Switch used to be, there is a connector there in it's place, then the wire comes back throught he firewall, across to the passengers side and back to behind the seat again then to the other pump.  Before we rewired the race car completely, we bypassed that 15 feet of wire and a half dozen connectors, with a 2 foot piece from relay to pump.  I'd wager your in the tank pump doesn't work.  They only lasted a couple years at best.  No big deal, the main pump will pull right past it.  It isn't needed and is a holdover from the original US import cars.  The Euro models had no catcon's and the fuel line was routed right where they put them for the US models.  The additional pump was implemented to prevent vapor lock.  Then sometime in 1982 or so, they re-routed the fuel lines and never eliminated the extra pump.  Most dealers were told to disconnect the wires to that pump on cars more than about 3 years old and yours may already be disconnected.  Don't worry about it either way, that's not your problem.
If you can wait a few more days until Steve gets back, I'll get my book and notes and tell you exactly what to do.  
I'm really sorry about the delay, but my son had an auto accident and totalled his car.  He is in the hospital but OK.  His cherry 1972 Dodge Charger is a mess.
If you want me to follow up on this, please just drop me a note at <doc1590@yahoo.com> and I'll stay with you as long as it takes.  Tell me where those jumpers that you removed were.  Also, your charging voltage seems a tad low.  It really should be in the high 13's.  But that's not your relay problem either...
Please send me an email if you still need my help by this weekend.

dave