Re: dead Bosch FI fuel pump

["Giller,Bruce C." <bgiller@domain.elided>]

	Thanks to all the fellow listers who responded to my query about dead
fuel pumps.  What follows is a condensed version of my weekend events;

	The car would start but would die within 10 - 20 seconds; then wouldn't
start until it had 'rested' for awhile.  Determined that when cranking
(but not starting), the fuel pump was buzzing.  Tested the in-tank fuel
pump and found that it was pumping gas quite well.  Removed the outlet
hose from the main fuel pump, applied 12 v from the battery and it
pumped out gas with a reasonable volume and pressure.  Replaced the fuel
filter.  Tested the fuel pressure at the cold start injector and the
pressure made it up to 38 psi which is ok according to my Alfa mech. 
Tested for spark at the plugs and found there was spark - replaced two
plugs with some spares (would have done all four but only had 2). 
Removed the cap and rotor and found out that the center HT carbon button
was no more (no idea where it went to) and the HT was arcing to the
rotor for there was pitting on top - replaced both the cap and rotor. 
Still wouldn't stay running.  My Alfa mech. suggested that the battery
was low (had been doing a lot of starting and even used the starter to
get the car to the side of the street) and I should try another one. 
Used some jumper cables from a running car as  a substitute for another
battery - still not working.  Tested the voltage at the pump when
cranking and when it started once the reading was 11.8 v but when
cranking but not starting was at 9.5 v.  Here endth Day Oneth.

	Day Twoeth.  One of the recent notes on this list was about how the
ground to the ECU could go bad and an auxiliary ground was required. 
Tom Evans gave me excellent notes as to where the fuel and main power
relays were located (my Spider manual was worthless in this respect). 
Checked the inline fuse near the ECU and the ground screw - both in good
order.  I spliced in a ground wire to pin 31 on the fuel relay and
attached the other end to the grounding screw right by the ECU.  Still
wouldn't stay running.  Jumped the fuel pump relay so that the pump ran
all the time - still wouldn't stay running.  Started checking the
voltages at the two relays.  The main power was getting around 12.5 v
but would drop to around 10.4 v when cranking.  The fuel pump saw about
10.3 v when cranking.  I was running out of ideas, so I decided to
re-charge the battery.  Put the charger on it and the needle dropped
down almost to the 'exhausted' stage even though the starter cranked so
well.  Left it on for about 2 hours (did some landscaping work
inbetween) until it was fully charged.  Checked the voltage at the main
power relay it was now at 13.4 v.  And, of course, the car started right
up and stayed running.

	One supposition is that I needed the extra ground for the ECU but after
the continuous starting attempts, the battery was to drained to supply
the necessary voltage (I thought it was 10v but Tom sez it should be at
least 10.5v) to the ECU all the time.  Or it could be that the battery
is slowly going flat - after charging the battery, the voltage was 14.8v
at idle which would indicate that the charging circuit was ok.  

	I did drive the Spider to work today and will check the battery voltage
after getting home to see if it has gone down.  Wanted to check the
water levels but it is a 'maintenance free' battery (only 3 years old).

	Bruce

	'73 GTV
	'86 Spider

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