2.3L ('83-'97) Fuel pump runs a long time when key is turned to on position

[rootebaga]

1991 2.3 5spd. Fuel pressure is lost quickly when engine is just down. When key is turned on, the pump runs a long time before it stops. I have already changed the the fuel filter, fuel pressure regulator, and the fuel pump. NO large improvement was noticed. Interestingly enough, if you turn the key to the "ON" position and wait awhile until the fuel pump stops running, the pressure will stay up. I have left the key on for an hour and the pump did not come on. I assume that means the pressure integrity of the system is acceptable. I really don't know which way to go next, the truck has been a daily driver for 11 years and I want to fix it. I also have an 83 and an 86, one with a 2.0 carb. motor and one with a 302 V8.

 

[tomw]

When the pup keeps running, are you able to start the engine? The long run is sometimes a symptom of failing capacitors on the EEC board. You can remove it and open it up for inspection if you wish. The capacitors that seem to fail after being in use for years are electrolytic, and they will start to leak onto the board. If you don't have that, it could also be the board itself. A sticking fuel pump relay could also make the pump continue to run.
tom

 

[RonD]

+1 ^^^

You will need to pull out and open up your computer, and replace the 3 blue capacitor

Picture here of computer, yours will look similar but not the same: http://www.auto-diagnostics.info/ford_eec_iv

"I assume that means the pressure integrity of the system is acceptable"
Just FYI
There is no fuel pressure sensor on Rangers, the fuel pump comes on for 2 seconds with key on, period, just a simply timer circuit
Then if computer sees RPMs above 400 it will turn fuel pump on full time
So you have a computer problem

 

[rootebaga]

When the pup keeps running, are you able to start the engine? The long run is sometimes a symptom of failing capacitors on the EEC board. You can remove it and open it up for inspection if you wish. The capacitors that seem to fail after being in use for years are electrolytic, and they will start to leak onto the board. If you don't have that, it could also be the board itself. A sticking fuel pump relay could also make the pump continue to run.
tom

The pump runs for awhile and when it stops, then you can start the engine. I have also replaced the fuel pump relay. The EEC or PCM on this truck is located in the passenger kick panel. It is pretty easy to get at so I would think it will be the next avenue of inspection. If the capacitors are leaking I should be able to see it, but if the board is bad I guess replacing the EEC is the next move.

 

[rootebaga]

+1 ^^^

You will need to pull out and open up your computer, and replace the 3 blue capacitor

Picture here of computer, yours will look similar but not the same: http://www.auto-diagnostics.info/ford_eec_iv

"I assume that means the pressure integrity of the system is acceptable"
Just FYI
There is no fuel pressure sensor on Rangers, the fuel pump comes on for 2 seconds with key on, period, just a simply timer circuit
Then if computer sees RPMs above 400 it will turn fuel pump on full time
So you have a computer problem

Very nicely put, I was looking all over the place for a fuel pressure sensor. The EEC is definitely the next move. Thanks...

 

[RonD]

I had to replace my 1994's 3 caps this year, one symptom was fuel pump running longer than 2 seconds, but engine also stumbled, I had 2 bad ones but replaced all 3, under $5 to fix
Been running great ever since

 

[Curious Hound]

I had to replace my 1994's 3 caps this year, one symptom was fuel pump running longer than 2 seconds, but engine also stumbled, I had 2 bad ones but replaced all 3, under $5 to fix
Been running great ever since

That makes sense. Capacitors are often used to set times in circuits. You can build a circuit to charge a capacitor in a certain amount of time. When the circuit senses that it is fully charged, then something else can be made to happen.

 

[JohnG]

Sorry to hijack but do failing capacitors also cause the opposite problem? Fuel pump not priming long enough? My sons full size will only prime for a split second so we can’t get it running

 

[adsm08]

Sorry to hijack but do failing capacitors also cause the opposite problem? Fuel pump not priming long enough? My sons full size will only prime for a split second so we can’t get it running

They can.

There are ways to get the fuel pump to run manually, bypassing the computer's control of it, that would allow you to build enough pressure to start the engine.

 

[Curious Hound]

Probably could. Don't just guess. Check fuel pressure. Also, you can test fuel pump operation by bypassing the ecu to turn on the fuel pump relay, using a jumper at the test connector in your engine bay.

Connector looks like this. I believe you run a jumper from the fuel test port to ground.

 

[tomw]

Wife's 97 T-bird would not start... fuel pump would run and run and ... and when it finally stopped, THEN the engine would start. Looked at the board and found no visibly bad caps. Replaced a surface mount, but it didn't help. Got a re-man(ha) board, and it now works.
This is just my experience. The run time seemed(to me, she's doesn't 'get' cars) to increase over time before the pump would time out and allow the engine to start. Swapping the ECU in the kick panel is NOT fun as I seem to have too big shoulders and too short arms...
tom

 

[rootebaga]

Very nicely put, I was looking all over the place for a fuel pressure sensor. The EEC is definitely the next move. Thanks...

I pulled out the computer and opened it up. It has two (2) blue capacitors. Both looked really good with no leakage. Their was a lot of trash inside the computer, I'm guessing from Hurricane Sally this year. I pulled out the board, cleaned the contacts and everything else to the best of my ability, reassembled it and reinstalled it. To my utter amazement it started working properly. How long it will continue I have no idea. I want to thank you guys for all your help. Would not have been able to fix this problem without you.

 

[RonD]

Good work

Thanks for the update and the FIX

You should probably have replaced the caps but at least you will know where to look if similar issues pop up, they will leak at some point