Fuel Pump not coming on.

[ALLBoostAWD]

The car has been sitting for a while now and recently the CAS went out. I replaced that in hopes of getting it started, now my FPR gauge reads 0 and I cant hear the fuel pump turn on. Is there a fuel pump relay or does it work of the ignition fuse? I am lost thinking there is a fuse/relay for the fuel pump so I can begin there. Please help. I dont have a test light currently so i cannot check to see if power is going to the pump, actually Im gonna go buy one now. Ill post back up if I have power.

 

[GSX93DSM]

You could try rewirng the fuel pump directly to the battery and see if that helps.
www.vfaq.com go to fuel pump.

 

[Woodsy0]

There is a fuel pump relay. I totally forget where I saw them being sold online, but you can try buying a new one and swapping that in, to see if it solves your problem.

 

[ALLBoostAWD]

I could, but throwing parts at a vehicle when you dont know whats wrong with it usually doesn't do too much good. I just bought the test light but now its raining, damn Alabama.

I had it rewired at one point but the instructions I had or the relay I got was wrong. The pump would have constant power, hooked it up to a switch and it fried the switch so I put it back to stock. I may have to try it again though.

 

[steve]

The MPI relay on a 1G is two relays in one package. The fuel pump relay is one of those.
It's has two inputs. One from the starter circuit and one from the ECU. The starter input goes to battery voltage when the car is cranking to turn on the pump and the ECU input goes to ground when the ECU sees the CAS signals telling it that the engine is running. Either of these will cause the relay to switch power from the ignition fuse on the battery to the fuel pump.

You can test the ECU part using a datalogger, you can test the pump by connecting the check connector under the hood to the battery positive. The input from the starter you just have to measure at the relay. The MPI relay is located on the passenger side of the cenert console on the outside.

All of this information is in the factory service manual.

Steve

 

[ALLBoostAWD]

Got it, Shorted wire after the connection from the vehicle to the pump itself. Thanks for the help though.

 

[steve]

Somebody break the insulators where the wires pass through the top of the fuel pump assembly?

Steve

 

[4GSixty3]

Would the mpi relay, if bad, have anything to do with a 1992 laser 2.0 not getting spark as well as fuel? I turn the key over and I hear no fuel pump so fuel is an issue but my main question is ; Does the MPI relay under the ecu have anything to do with no spark if it's bad?

 

[steve]

The MPI relay on a 1G is two relays in one box. One is for the power to the MPI system and the otehr for the fuel pump. Both sides get their power from different sources so unless the relay is really really bad it doesn't usually effect both at the same time.

Since your question isn't the same as the OP, please start a new thread. Make sure you have a wiring diagram for your car and that you have done the basic inital testing like making sure the fuses to the MPI and ignition systems are good and that your ECU is powering up. You can find references here my searching the archive.

Steve

 

[jab-619]

Where can you get a new relay?? I have the same problem. But my relay is clicking. It turns the pump and car dies. I know the ecu is good. I've checked everything I could think of. So it has to be the relay.

 

[Froyd79]

Where can you get a new relay?? I have the same problem. But my relay is clicking. It turns the pump and car dies. I know the ecu is good. I've checked everything I could think of. So it has to be the relay.

Sure its not the CAS? Anyway Mitsubishi graveyard has an ebay store sells those relays cheap! there is a link to the store on the website.