Wiring diagram on 93 buick roadmaster from fuel pump to relays an fuses

Fuel pump relay maybe . Do you know what a relay is an how it works ? Wiring diagram's here http://www.bbbind.com/free_tsb.html Enter vehicle info. Year , make , model and engine size . Under system click engine ,then under subsystem click fuel control's . Click the search button then the first blue link. Scroll down to the #6 diagram . This is the fuel pump electrical circuit . Use a test light or volt meter an test .

you will need to check the plug to the pump on top of the tank. check for voltage. then if no volts trace the wires back. also you should check the relay have some one at the relay listening to see if it clicks when you turn the key. no click no volts no volts may be a warn out relay, if it buzzes change it.

Begin by checking fuses. Ignition, efi, fuel pump fuses. When key turned to on, do the warning lights and gauges work? That verifies switch has power and is sending power out. With key on, the coil primary wire to coil packs should have voltage.

No spark and no gas? Fuel pump fuse good? I think I would use a test light or multimeter to check that fuel pump fuse terminal has power to it with key on. If that's good, pull connector off at fuel tank and check for a voltage signal on fuel pump wire when the engine is cranking-if good signal, fuel pump needs taken out for replacement or inspection. If no signal check that fuel pump relay has power to it. With key off, pull the relay and check that one terminal has power to it-the feed wire for the pump. If no power signal at all, check maxi fuses or fusible links for a failure.

I am truly stumped!! Help!!! ???? It's not that difficult if you know how to test electrical circuit's using a wiring diagram an a DVOM - digital volt ohm meter . Free wiring diagrams here http://www.bbbind.com/free_tsb.html
Enter vehicle info. year , make , model . under system click on engine ,then under subsystem click on charging system . Click the search button ,then the blue link . Looking at the diagram on the left , i see the ignition switch ,the crank fuse in the I/P fuse box, the theft deterrent relay an the starter solenoid . Using a voltmeter or test light check for B+ voltage at the S terminal on the solenoid while someone tries to start the vehicle . If no light or B+ voltage ,back track to the relay , Test for B+ voltage at pin's 30 & 87 while cranking . If you pull the relay out of it's socket an look on the bottom or side you will see four set's of numbers 30 & 87 and 85 & 86 . You could just take a piece of wire ,heavy gage 12 . Jump 30 & 87 . If the heavy gage battery cable to the starter is good it should crank the engine .
Starter Voltage Drop
How to Diagnose No Crank No Start Issue Nothing or only Click When the Key...

Well for starters, you need to diagnose the problem before replacing anymore parts. I say this because you mention both the fuel pump and sensors dealing with the ignition system which are 2 separate main things. Basically it takes 2 things to make an engine start, fuel and spark at the spark plugs. You need to narrow down what is missing because it seems since you replaced sensors dealing with spark and then you mention the other need fuel. I'm not sure as to where to start to help until whatever is missing is diagnosed and then find the cause of the loss. There are a couple of things you can check. Below is a picture of the relay box in the engine compartment. With the help of somebody put a finger touching both the fuel pump relay and the EGI main relay. While touching them have somebody turn the key to the "on" position (no need to try and start). When the key is turned on you should feel a "click" inside both of those relays. The fuel pump relay will click for about 3 seconds and the click again to shut off. The EGI main relay should stay on. If both seem to be fine you need to make sure of the fuel pump gettting "juice" and for power to the ignition system like the coils. You can get to the power/juice wire at the fuel pump pretty easy. You can access the connection at the fuel pump by lifting the lower part of the rear seat. Once the seat is lifted you should be able to see a part in the carpet that is cut to be able to lift the carpet up and access the plate covering the access to the fuel pump and/or the top of the fuel tank. Using a test light, check the green and yellow wires at the fuel pump. You should have power at those wire when turn the engine over or if the key is just turned to the on position you should have power there for about 3 seconds. To begin checking for spark or power to the ignition system you need to make sure you are getting power to the ignition coils. The red and white wires at the coils are your power wires. Check those. Also you can check the power at the fuel injectors. When the key is turned on or when trying to start, you should have power to the green wire at each of the fuel injectors. You should have constant power/juice at each of the fuel injectors. This is where I would start to narrow down the loss. Start here with these tests and let me know how the tests come out by replying/commenting here or you can email me directly at [email protected] ith what you have found out. Once the first tests are done and I know what the results are, we can go to the next step with a couple of other tests to figue the problem out. If one of the relays don't "click" then you have a possible bad relay. The EGI main relay is a common thing to go as well as the fuel pump relay. Don't mind helping and there is no cost to you for it but I don't want to tell you to start replacing parts until the problem is located. Hope this helps get you started.

Have you checked the fuel pump or fuse? First check for a blown fuse. I belive that is an electrical pump, when you turn the key on with engine off, you should hear a slight whine. The whine is the pump turning on and sending fuel to the enigne. Another way to check is to hook up a fuel presseure gauge to the fuel rail on top of the motor. There will be a rail that conects the fuel line to the injectors the rail is near the spark plugs, there should be a "capped" connection on the end of the rail. Remove the cap, hook up your gauge and check the pressure. Pressure varies w/ model, but it should be above 20psi. If you don't get a reading with the key on that indicates the problem is with the pump or the wiring going to the pump. Do a quick voltage test with the pump connections if you get 12 volts the pump is bad, if not there is damage to the wiring, a fuse is blown or the solenoid for the pump is bad. Avg life for a fuel pump is 100,000 to 150,000miles

Theres a few more checks But i'm sure you checked the fuel pump fuse already ..Use a test light and check to see if the fuel pump relay is getting power from the supply and from the Ignition feed. should be a schematic on the underside of the relay..if no power from the feeds check for a blown or rotted fuseable link or a maxi fuse..good luck

Fuel Pump RELAY & FUSE CHECKED & DO you Have POWER "TO" Fuel Pump ? ALSO OIL Sending Unit Supplys the GROUND To Fuel Pump , This is A Saftey FEATURE that Shuts Down Fuel If ENGINE Looses OIL PRESSURE . And If This OIL Sending Unit or also Called (OIL PRESSURE SENSOR) << If It FAILS it WILL Cause What Seems Like A Fue Pump Problem But Is Rally Just The Sensor that is BAD. HOPE this Sheds Light on Your Problem !

If the starter is good, a bad ignition module or failed fuel pump will produce similar symptoms, i.e. no cranking, nothing happening when you turn the key. Ignition module sits under the distributor cap and is about the size and shape of a cassette tape with 2 female plugs and one male plug. Quick way to check the fuel pump is to put the car in a quiet place like inside the garage. Find a quiet friend to sit behind the wheel and turn the key so the dash lights come on, DO NOT TURN THE KEY FULLY LIKE YOU'RE TRYING TO START. You get down on the ground and listen near the gas tank for the quiet hum of the fuel pump that tells you it is working.

There is no fuel reset button on this van.

To test the circuit before removing the tank, you will need a voltmeter or cheap test light. Disconnect the connector at the fuel tank. On the harness side, locate the gray wire (fuel pump wire). Connect the test light to a good ground. Have a helper crank the engine over. While engine is cranking, the gray wire should have power. If it does, and the pump is not turning on, then the pump must be bad and need replacing. If there is no power on the gray wire with engine cranking, the circuit is the problem, not the pump. Go back and find the fuel pump fuse in the junction block (the fuse relay block where the fuel pump relay is). Check the fuse, also check if there is power going to the fuse. This fuse should be hot at all times. The circuit goes from battery to pump fuse to fuel pump relay to gas tank and the fuel pump.