1976 fuel injected eldorado convertible

[bcroe]

I have seen close to a hundred 500 engine ECUs for repairs over
a dozen years, those cars are out there.  Bruce Roe

[dennisspeaks]

I am glad I sent my ECU in to you for updating Bruce.  Is the ECU for the EFI the same as carb cars?

Although they all need updating, at close to 100 I bet you have seen some really poor condition ECU's and some in good shape as well.

I have seen close to a hundred 500 engine ECUs for repairs over
a dozen years, those cars are out there.  Bruce Roe

[bcroe]

I am glad I sent my ECU in to you for updating Bruce.  Is the ECU for the EFI the same as carb cars?

Although they all need updating, at close to 100 I bet you have seen some really poor condition ECU's and some in good shape as well.

A carb does not need a computer.  The ongoing problem with these
EFIs is replacement parts.  The ICs are not marked, but it is
possible to figure out the generic equivalent by watching them
operate.  Some common failing parts have been recreated as good
or better than new, or may be in the future, by owners like Scott
Kent, Waldo Du Toit, Mike Przybyle, James Ward, that reprinting
service on Evil Bay, myself, and others.  The General built them
like radios, using a pair of cheap, one sided printing circuit boards. 
It had no plated thru holes, so traces easily come loose.  And solder
joints are a lot more likely to fail (cracked around component lead)
with no hole plating, did not help they skimped on solder, fixed one
today that worked if you banged it.  And dozens by dozens of wire
jumpers are required, to compensate for lack of traces on the other
side. 

Still a problem is the 26 pin connector, and several
custom design (that means unobtainable) ICs.  Bruce Roe

[dennisspeaks]

That's good to know Bruce, i don't feel as bad that I missed out on the 75 Eldorado that was at my local pick and pull and missing out on the ECU that was not there.  Sad that they crushed it so quick, even worse that someone beat me to the interior.

A carb does not need a computer.  The ongoing problem with these
EFIs is replacement parts.  The ICs are not marked, but it is
possible to figure out the generic equivalent by watching them
operate.  Some common failing parts have been recreated as good
or better than new, or may be in the future, by owners like Scott
Kent, Waldo Du Toit, Mike Przybyle, James Ward, that reprinting
service on Evil Bay, myself, and others.  The General built them
like radios, using a pair of cheap, one sided printing circuit boards. 
It had no plated thru holes, so traces easily come loose.  And
dozens by dozens of wire jumpers are required, to compensate for
lack of traces on the other side. 

Still a problem is the 26 pin connector, and several
custom design (that means unobtainable) ICs.  Bruce Roe

[dennisspeaks]

I was reading on hemmings a article by a guy who says he used to work on these EFI's that the major problem is that people didn't know how to start them, they would press on the gas and flood them plus the technicians didn't know how to work on them, parts were super expensive and the gas back in the days was not compatible with EFI engines.

[79 Eldorado]

Turn the key to run/on but not to crank. Allow about 3 seconds; you will hear the pumps run and then stop. Once you hear the pumps stop running turn key to crank position and the car normally starts within a few seconds if all is correct.

Scott

[bcroe]

I was reading on Hemmings a article by a guy who says he used to work on these EFI's that the major problem is that people didn't know how to start them, they would press on the gas and flood them plus the technicians didn't know how to work on them, parts were super expensive and the gas back in the days was not compatible with EFI engines. 

I suppose an EFI system originally cost a lot more than a carb and a mechanical
fuel pump.  Even more so if a low volume item.  That is not so much true today. 
There was little fuel injection performance advantage, unless you were flying
a fighter plane in a negative G situation.  But new emissions requirements,
along with fuel economy needs, turbos, and some multi fuel operation,
changed all that. 

Mechanics typically were not noted for their expertise in complicated
electronics.  More training needed.  I am not a mechanic, though
having learned some trial and error expertise in maintaining a single
type of equipment for half a century. 

New devolpments, with time and budget pressures, and some more expedient
than sound designs, may have some bugs which show up over time.  The 70s
Cad EFI certainly had a few.  With the benefit of 20-20 hindsight, some owners
of these 70s EFIs have done a lot to rectify these long term problems. 

As for starting, I have some opinions developed over half a century, running
some of the Generals V8s.  I know that the more times a starter turns an engine
before it starts, the sooner I will be pulling the starter for new brushes and maybe
more.  So I very consciously try to get the engine going very quickly, best on the
first turn. 

I first give a carb at least 2 hard throttle pumps, to get gas into the
engine BEFORE I crank the starter.  Most times the engine will start
instanly, sometimes (carb not filled) a bit of pumping might be needed
to avoid an initial stall

How does the 70s Cad EFI start?  They wanted to remove any action
requirement from the owner.  A coolant sensor enables temporary
cold enrichment for a cold engine, like the choke on a carb.  There is
also an additional enrichment, which quickly fades after the starter is
released.  BUT NONE OF THIS HAPPENS UNTIL THE INJECTORS OPERATE. 

A bank of 4 injectors will not fire until the starter triggers a speed sensor
contact to close, possibly a whole crank turn.  This is timed to happen
JUST AFTER the intake valves of those cylinders have closed.  So then
those cylinders will have a compression stroke, a sparked combustion
stroke with NO fuel, an exhaust stroke, then an intake stroke of the
charged air, and a compression stroke.  The starter must turn the
engine 2.5 TO 3.5 REVOLUTIONS before there is any chance of firing
a cylinder. 

The General decided to defeat carb guys like me, so pumping the EFI throttle
HAS NO EFFECT when the starter is operating, the injectors are inhibited.  But
I defeated him, I turn on the ignition (to run the fuel pumps), pump it a couple
of times, THEN operate the starter.  Just like my carbs, INSTANT START.  Every
time I fail to do this, I regret the resulting slow start.  Some day I will modify
my personal 79 ECU, to remove the start-pump inhibit (for the times I forgot). 
Better yet, do the initial pumps for me. 

Will this work for you?  Try it, you will like it.  Bruce Roe