Hi, I have a '76 Eldorado with the electronic fuel injection system, the fuel pumps don't seem to be turning on when I cycle the key on, but they do work I've tested them. I have spark and if I give the car a shot of gas thru the intake it will start. So I was wondering what would cause the fuel pumps not to turn on when I go to start the car. I parked the car a few years ago and it was running, now that it's sat no luck. Any thoughts are appreciated, I can't wait to get this car back out on the road where it belongs.
Thanks, Chip

Did you check the pump fuse near the ECU ?? There could be a poor connection at the ECU jumper harness,and/or the fuel pump jumper harness near the ECU (under the panel). A dark green wire specifically.
Bad connection or open connection in the coolant sensor (cold engine only).
Bad connection at the distributor trigger. Distributor trigger stuck closed.
The throttle position switch could be shorted on the high end ( wide open throttle position) Disconnect it and check if the engine will start.
Could also be a fuel flow restriction somewhere, like maybe in the filter ??
The coolant sensor may be in the heater hose on that car. The connectors back in 1976 don't have the weather proof bellows type seals like new stuff does, so un-plugging and moving the connectors in & out a few times may get them to work better. Corrosion in those at this date may be the problem.

Hope this helps a bit........ BILL

Hi Bill, Thanks for the response, I've been cleaning connections here and there and trying to figure out which wires go where. Is there a good shop manual out there for these cars? A wiring diagram would be really handy. I'll check into the things you said, I also found out by using a noid light that I do not have injector pulse at my injectors. Also I found a relay under the glovebox that was near the heater box that was very rusty and I doubt would ever work, it has a single pink wire going into it and a 3 prong conector into it as well with a green wire and 2 other wires I can't remember the color of off the top of my head. Could that have anything to do with the fuel injection or is it something else?
Thanks, Chip

Get an original GM shop manual (I think the one you need is the red cover), it will pay off in the end. They're on ebay and they cover just about everything you need to know. I have one for each car and am constantly using them. If you're patient, sometimes you can get them for cheap ($10-20).

Your fuel pumps are powered by a wire direct from the ECM.. I do not see any relays in there....So by that I would say you lost power to te ECM or the ECM is bad...

There are grounds listed on the right-hand fender support. You may want to look for them. They are ; black for the ECU, EGR solenoid, and the fast idle heater element. The grounds would be as important as the rest of the system connectors etc, and the ECU depends on that fender support ground to operate. so you may want to search for them. That set-up has a fuel pump in the tank as well as one mounted under the car in the fuel line.
The throttle position switch seems to have a wiper that swings across contacts as the throttle angle changes. That is listed as one of the no-start items to check out.
That dark green wire I mentioned is the feed wire to your fuel pumps, from the ECU. If you can locate that, put a meter or test light on it and check for voltage when you try the starter.
Don't know what the relay you mentioned is for, but it's not in the fuel system.

I've seen the fuel pump wire connector melted and loose where it plugs into the ECU. Over the years the hi amperage thru this wire melts the connector causing intermittant no voltage to the fuel pumps.

The "hot wire" scenario sounds about right. If one of the pumps gets worn and starts drawing more than design wiring. Good call on that carnut :D

You should hear the fuel pumps run for several seconds when the ignition is switched on. There is a fuse to the ECU, the ECU contains the fuel pump relay. The relay & the ECU pins often burn out, I have a fix for this on my PHOTO BUCKET site (search user id bcroe) using an external relay. Also shown is testing of ECUs, available for postage.

Also check the engine temperature sensors, should measure around 1000 ohms cold. Do the 21 click test to see if the injection works at all. I have a check list if I had your email, my user id is on juno dot com

Bruce Roe CLC advisor, # 14630

I have shown on PHOTOBUCKET (user bcroe) how to avoid failures due to overloaded relay/connector/ECU wires in the fuel pump circuit.

Bruce Roe CLC advisor #14630