fuel pump keeps running
Senior Member
Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
man!
Heres how the system works.
Starting from the pump back to the EEC.
1. Pump has seperate power applied thru an operated relay and crash sensor.
2. The relay is operated by a ground from the EEC when the engine is running.
3. Turning the ignition to run powers the EEC and causes it to put a temporary ground to the pump relay for about 2 seconds then it stops until cranking starts.
For the pump to run after turning off the engine, there would have to be a false ground to the pump relay or the relay contacts are stuck closed.
Normally the pump can be run with a ground applied to one terminal of the engine test connector with the ignition to run position.
When the pump runs in a fault condition, pull the relay to see if it stops.
If yes, check for a ground to the relay winding. If yes, you found the reason, then find it! Probably a rub thru some place.
Heres how the system works.
Starting from the pump back to the EEC.
1. Pump has seperate power applied thru an operated relay and crash sensor.
2. The relay is operated by a ground from the EEC when the engine is running.
3. Turning the ignition to run powers the EEC and causes it to put a temporary ground to the pump relay for about 2 seconds then it stops until cranking starts.
For the pump to run after turning off the engine, there would have to be a false ground to the pump relay or the relay contacts are stuck closed.
Normally the pump can be run with a ground applied to one terminal of the engine test connector with the ignition to run position.
When the pump runs in a fault condition, pull the relay to see if it stops.
If yes, check for a ground to the relay winding. If yes, you found the reason, then find it! Probably a rub thru some place.
Senior Member
Joined: Sep 1999
Posts: 3,083
Likes: 0
From: Ventura, California
When the relay contacts are stuck closed, or there is a 'false ground', the engine will still start. When the pump runs continuously and the engine won't start, 99% of the time the ECM needs to be replaced. If you are unable to pull any codes while this is happening, then it's definitely a bad ECM.