Galant VR4 starts - won't stay running!

[MOTORHEADMIKE]

91 galant I picked up that a buddy had sitting for four years. Swapped motors.. Now has 7 bolt engine, stock EVERYTHING (car is for wife). There was some nasty sludge in the gas tank after four years and we cleaned it. Replaced injectors & fuel filter.

The car turns over perfectly then dies almost immediately. Will idle 3 seconds at most, you can rev it up, but it will NOT stay running. It smells like a lawnmower. Just tried changing TPS, no difference. Injectors have power and are keeping power.. Help?

 

[805DSM]

Make sure that all couplers are conected and that u dont got any boostleaks. Specially in the throttle body . Also make sure the Mass Air Flow sensor is connected or even working. And also check the fuel pressure , the fuel pump might be going out.

 

[Russman1986]

Check the fuel pressure for sure.

 

[Brandon Mau]

4 years is a long time. But you should check the maf sensor as stated, also get yourself a volt meter and check the coolant temp. sensor. The wires on these cars turn brittle from being so old when you did the motor swap you may have weakened a couple of the connectors. Just do a once over before replacing anything and start performing checks with the volt/ohm meter.

 

[toybreaker]

Make sure that the ecu capacitors have been changed.

They have a nasty tendency to leak while a car is down for an extended period.

The electrolyte that leaks from the capacitor casing contains boric acid and amonia salts and will damage the ecu board, leading to all kinds of problems, including the one you are describing.

After you have investigated the ecu, it's time to start checking the basics relating to the fuel pump system.

The fuel pump runs anytime the key is in the start position.

After the engine starts, the ecu controls the fuel pump operation by grounding one leg of the fuel pump relay coil, located inside the mpi relay.

If the ecu doesn't "see" the engine running, the ecu won't ground that leg and you wont have power at the pump when you release the key to the run position from the start position.

To check for this, remove the fuel pump cover plate (in the trunk under the carpet, drivers side) and check for power on the black/white wire.

If there is power there while cranking, but it goes away a few seconds after the engine starts, you will be checking the mpi relay/crank angle sender and a few other things related to the fuel pump control circuit.

Good luck, and check out that ecu PRONTO!!!

It's a common problem that left unrepaired will cost serious money to remedy.