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2.3L Ford from 1990 Tempo


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jethro
Novice

Mar 22, 2012, 12:44 AM

Post #1 of 14 (2648 views)
2.3L Ford from 1990 Tempo Sign In

Symptoms:
Takes multiple attempts to start, not firing, sputering once or twice then finally catching on and running fine for a few seconds then will die if throttle not bumped every few sec until it warms a bit. Holding key slightly on seems to help.(ie not fully releasing after starter engagement)

Will die when put in gear if not massaged. Once on road, will accelerate slowly to about 55-60 w light throttle application. If too much, dies. Releasing throttle and lightly depressing will usually cause it to resume running.

Actions:
Fuel pump relay works(can hear, feel it clicking) tried a new one, same result.
Fuel pump energizes for a sec.
Fuel pressure at rail sometimes zero, sometimes 12 psi, sometimes 24-25. Seems no rhyme or reason as to what reading.
Fuel presssure regulator replaced and helped slightly - accelerates a little better when it does run, but still dies if throttle pushed more than slightly.
Voltage at fuel pump is 7.06. Momentarily reads 12v when key on or starter engaged(about 1 sec) then goes and stays at 7(voltage taken from connector while not connected to pump.
Fuel pump "looks" ok....for what that is worth. Have a new pump but not installed yet as am doubtful it will fix problem. Esp after discovering only 7volts at the pump connector. Incidentally, I connected the plug back to fuel pump assembly(still installed in tank) and turned key on to see what happened...expected fuel to shoot out of pipe and got nothing.

Bottom line: Whether or not the pump sends fuel is unpredictable. Pressure seems low, and never starts on first attempt. Car barely driveable, and only w much finesse and gimmickery.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 22, 2012, 3:24 AM

Post #2 of 14 (2610 views)
Re: 2.3L Ford from 1990 Tempo Sign In

You already know you have a fuel pressure problem to get to the bottom of. If you are questioning the power supply arriving at the pump, then simply apply 12v from another source for testing purposes.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jethro
Novice

Mar 22, 2012, 8:12 AM

Post #3 of 14 (2587 views)
Re: 2.3L Ford from 1990 Tempo Sign In

I just wasnt sure if pump should have 12v continuous or if the drop to 7v at the pump connection was correct. If the voltage drops to 7 to protect the pump for extended operation, I didn't want to bypass and burn it up.

I will go put a 12v supply directly to the pump and see what happens.


Hammer Time
Ultimate Carjunky / Moderator
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Mar 22, 2012, 8:38 AM

Post #4 of 14 (2585 views)
Re: 2.3L Ford from 1990 Tempo Sign In

That wouldn't protect the pump, it would harm it.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
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Discretesignals profile image

Mar 22, 2012, 9:59 AM

Post #5 of 14 (2568 views)
Re: 2.3L Ford from 1990 Tempo Sign In


Quote
If the voltage drops to 7 to protect the pump for extended operation, I didn't want to bypass and burn it up.


If your dropping 4-5 V out before it reaches the pump, the pump is going to run slower than it was designed for which is going to cause low fuel pressure. You have high resistance somewhere in the circuit.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


jethro
Novice

Mar 22, 2012, 10:02 AM

Post #6 of 14 (2565 views)
Re: 2.3L Ford from 1990 Tempo Sign In

Connected 12v directly to pump and it runs and sounds good. I know this is barnyard, but checked the pressure with a tire pressure guage - multiple times, consistently got 19psi. Seems way low for a pressure reading at the outlet.

Also checked voltage at connector using a different ground and again got battery voltage for 1 sec w/key on, then 7v. If starter engaged, same cycle. This baffles me b/c I think it should be 12v steady. I read other accounts of the same voltage drop for Fords. I would like to be sure the power is correct before installing a new fuel pump that doesnt fix the problem. I thought using a direct ground might change the reading but doesnt. The 7v reading is also strange b/c it seems EEC voltage feeds are 5v. The fuel relay I swapped was the outboard one behind glove box. Not really sure what to do next.


speed
User

Mar 22, 2012, 11:00 AM

Post #7 of 14 (2531 views)
Re: 2.3L Ford from 1990 Tempo Sign In

As DS stated you have excessive ressistance in your feed wire somewhere. Ypu need to trace your power wire to the relay and see if there is anything thats causing resistance





GM ASEP 26 SCC Milford ASE certified in Brakes and Electrical on Thursday April 5th 2012


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Mar 22, 2012, 11:11 AM

Post #8 of 14 (2526 views)
Re: 2.3L Ford from 1990 Tempo Sign In


Quote
but checked the pressure with a tire pressure guage


Oh boy





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


jethro
Novice

Mar 22, 2012, 11:21 AM

Post #9 of 14 (2522 views)
Re: 2.3L Ford from 1990 Tempo Sign In

Ok then - Going to check the pwr feed wire now. Thanks


jethro
Novice

Mar 22, 2012, 11:25 AM

Post #10 of 14 (2521 views)
Re: 2.3L Ford from 1990 Tempo Sign In

I know...I know. But Hey, it worked. Its a direct reading guage and seems to give instant, exact readings.

The "professional" fuel pressure reading set I used the prev three times seems to lag and give vague readings - like there is too much flex/bleed in the excessively long line to the pressure guage.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 22, 2012, 11:45 AM

Post #11 of 14 (2516 views)
Re: 2.3L Ford from 1990 Tempo Sign In

Here is the spec and that's non-negotiable.


Key ON Engine OFF 50 - 60 psi (345 - 415 kPa)







~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jethro
Novice

Mar 29, 2012, 4:41 PM

Post #12 of 14 (2437 views)
Re: 2.3L Ford from 1990 Tempo Sign In

Problem solved: There is a flexible fuel line connecting the fuel pump to the metal fuel pipe going out of the tank. This line had deteriorated and a leak developed between the inner and outer sleeves of the fuel line where the nylon reinforcement braiding is. This allowed fuel out of the pump to be ported back into the tank - hence the inconsistent and insufficient fuel pressures. A replacement piece of fuel line solved it. I also replaced the fuel pressure regulator as this seemed to help it run smoother, and respond to throttle inputs better.

I still dont know why voltage drops from 12v to 7v after a moment, but car starts and runs properly now. I read on another blog where this occurs in other cars too, for example the Mustang.

Thanks Hammer and all for the inputs.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 29, 2012, 4:46 PM

Post #13 of 14 (2434 views)
Re: 2.3L Ford from 1990 Tempo Sign In

Real late model Fords use a Pulse Width Modulated feed from a module to vary the pressure but not yours. Yours is likely dropping because the pump is consuming too much current or you have too much resistance in the circuit somewhere. It's supposed to receive battery voltage at all times.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jethro
Novice

Mar 29, 2012, 4:53 PM

Post #14 of 14 (2428 views)
Re: 2.3L Ford from 1990 Tempo Sign In

The circuit was open when I was measuring voltage(unplugged and reading off the contacts)...maybe thats why.






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