1975 Eldorado fuel injection

[sedlockfarm]

My 1975 is fuel injected (one of 1400 made I was told)  is hard to start.  One morning you can turn the key and go the next time I might have to try for ten minutes and turn the key 25-30 times.  It eventually starts and once it does it is usually starts OK for the rest of the day.  Fuel pumps have been replaced, fuel pressure regulator has been replaced, and the sensors in the exhaust and cooling system are with in tolerance.  This car has less than 40,000 miles and is pretty pristine.  Help please.
John

[Dave Shepherd]

Does it have a fast idle after you get it started, I assume you replaced/checked the coolant temp sensor for efi also.

[76eldo]

When it does not start, try spraying a little starting fluid into the air intake.

If it starts with a shot of that, or at least tries to start, you may be having a problem with the relay in the CPU that energizes the fuel pump circuit.

One of our members, Bruce Roe has a fix for that and when he sees this post will probably post something that will help you.

Brian

[bcroe]

If a shot of fuel down the throttle body starts it right up, your cold
enrichment probably isn't working.  That could be caused by a bad
EFI temperature sensor, or a bad circuit in the ECU.  Check the
sensors, they should measure around 1000 ohms cold.  The coolant
sensor has the most effect; if open circuit, swap it with the air temp
sensor to get the car going. 

The cold idle air valve could be working, but it doesn't control enrichment. 

Sensors good, try another ECU, and/or get yours tested.  No charge
to get it tested here, if you pay postage.  Bruce Roe CLC # 14630

[sedlockfarm]

The EFI sensors are both within tolerance.  I did replace the analog computer (I think that is what it is called, located above the glove box) with one that was from a California car.  Some information says that a Cal. computer will not work in a midwest car? Any truth to that? Thanks for the information I will keep playing with it.
John

[bcroe]

The EFI sensors are both within tolerance.  I did replace the analog computer with one that was from a California car.  Some information says that a Cal. computer will not work in a midwest car? Any truth to that? Thanks for the information I will keep playing with it.  John 

A replacement ECU must be for the same size engine, 500 cu for you.  Any 75-76 full size (not Seville 350)
will work.  A CA computer should be fine.  My partial list says
Bendix #       car                    desc
160 8339  76 E Fed     orig 500
160 8340  76 E Cal      orig 500
160 8820  76 C Fed     remf 500
160 8822  76 E Fed     remf 500
160 8823  76 E Cal      remf 500
160 8868  76 C Fed     orig 500
161 1163  76 E/C Fed  orig 500

Just turning on the key, you should hear the pumps run a few seconds,
or the fuel pump circuit is bad.  Pressure should be 39 psi, maintained
briefly after the pumps stop.  Failing that, check where 12V is lost to
your pumps.  Could be the fuse, ECU contacts or internal relay, or pump
wiring.  A test light should find the problem.  Bad ECU, send it for repair. 
Good to get it tested anyway, esp if you have a spare. 

See the fuel pump wiring, upgrade on my PHOTOBUCKET, sub album
70s EFI, about picture 13 & 14.

     http://s93.photobucket.com/albums/l71/bcroe/

(that is a lower case "L"71, not an upper case "i"71)

  click on a Sub-Album
  click on a picture to enlarge + explanation       Bruce Roe

[sedlockfarm]

I'll have to check pressures, the fuel pump circuit is good, I always listen for the pump on the right side rail when I turn the key.  That fuse is under the dash on the passenger side.  I also listen to here if the injectors are opening.  I'm going to check my numbers.  Where do I send the ECU to be tested and or repaired.  What is the cost of testing and repair?  Thanks again
John

[bcroe]

I'll have to check pressures, the fuel pump circuit is good, I always listen for the pump on the right side rail when I turn the key.  That fuse is under the dash on the passenger side.  I also listen to here if the injectors are opening.  I'm going to check my numbers.  Where do I send the ECU to be tested and or repaired.  What is the cost of testing and repair?  Thanks again, John 

John, Contact me at email   bcroe at juno dot com     
Test just pay postage, can discuss any faults found.  Some PRIORITY MAIL arriving in
my AM, often ships back same day; UPS (8PM) adds a couple days.  Repairs may take a little longer. 
Bruce Roe    CLC # 14630
5719 East Skinner Rd
Stillman Vly, IL  61084        815 234-8039

[caddyfam]

Our 75 elc with 20k died on arrival at gn Boston.  Had spark and good fuel pressure, just would not light. Found Bruce Roe in membership directory and he spent ample time guiding me through troubleshooting.  He determined a faulty computer, sent one to our hotel, plugged it in and we were back in business and able to return home.  Bruce saved our vacation.  Also thanks to Greg Surfas for his help.  Lesson learned-carry spare computer, coolant sensor and fuel pump.  I am also changing the fuel pressure regulator with one with a Schrader fitting.  Doug Berg