Mechanics

FUEL PUMP NOT WORKING WHEN KEY IS ON

1993 Ford Tempo

Electrical problem
1993 Ford Tempo 4 cyl Front Wheel Drive Automatic

changed ccrm (fuel pump relay), engine computer, check coolant temp sensor and in specs range. The fuel pump will have a great chance to prime (2-3 sec) when the key is on when engine is cold but when it`s hot, I can't hear the fuel pump buzzing at all.

What are the diagnostic steps I can do to isolate the issu?

Is there a way to provide 12 volt to the fuel pump to test it out and not having to remove it in the tank?

Thanks,
Danny
Avatar
Dannyr2009
April 16, 2010.



1. Release fuel pressure. Install fuel pressure gauge. On all models except 1.8L and 2.0L A/T, connect a jumper wire between ground and fuel pump test terminal at the Data Link Connector (DLC). See Fig. 1 . On 1.8L and 2.0L A/T, connect a jumper wire between ground terminal (Black wire) and fuel pump terminal (Light Green wire) at the Data Link Connector (DLC). On all models, turn ignition on, but DO NOT start engine. This activates the fuel pump. Fig. 1: Identifying Data Link Connector (DLC) Terminals Courtesy of FORD MOTOR CO. 2. Measure and record Key On, Engine Off (KOEO) fuel pressure. Start engine. Measure and record Key On, Engine Running (KOER) fuel pressure. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. Turn ignition off and monitor fuel pressure for one minute. Fuel pressure should not drop more than 5 psi (kg/cm 2 ). 3. If fuel pressure is within specification, test is complete. If fuel pressure is not within specification, check fuel filter and lines for restriction(s). Repair or replace as necessary. If fuel pressure is still not within specification, install fuel pressure gauge (if removed). 4. Start engine and observe fuel pressure gauge. Gently squeeze fuel return hose. If fuel pressure increases while squeezing fuel return hose, replace fuel pressure regulator. If fuel pressure does not change while squeezing fuel return hose, check for plugged fuel inlet strainer or defective fuel pump. Repair as necessary. CAUTION: Do not activate fuel pump for long periods, or engine may hydrostatically (liquid) lock. CAUTION: Inspect fuel system for leaks or damage before testing fuel pump.
4/16/2010 ...


http://www.2carpros.com/forum/automotive_pictures/62217_FP_Specs_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_fuel_pump_test_2.jpg


Merlin2021
Apr 16, 2010.
I did another ride today, 80km and when I shut the car, same thing happen no fuel pump sound when I tried to restart it.

I don't have a fuel pressure gauge so I decided to skip that step and procede with the next step. I was sure that no pressure was provide by the pump because I can't hear it at all.

So I tried what you suggest me. At the driver strut tower, I found an EEC connector. (I guess it's the same thing as DLC) Remove the cover and found 6 connector total. (Same as your ill bellow)
I have a test light so I poked the connector -bottom row, last connector at right and hooked it to the ground of the battery and nothing (while the key was turned to on position). After a sec or two, the test light light up maybe half bright it suppose to, telling me it has about 5 to 6 volt of current but no sound of the fuel pump.

What should I try next?

Thanks alot for your help,

Danny

Tiny
Dannyr2009
Apr 18, 2010.
Ok, same situation. Stop car when engine was hot (200km ride) and tried to restart it, no fuel pump buzzing. So pop the hood and insert paper clip in eec harness, fuel pump test terminal and ground the other end with the batt terminal, turn the key to on and heard a click at the fuel pump relay I would guess but no fuel pump buzzing at all. Pop the trunk and remove the inertia switch from harnest and insert paper clip into the input and output terminal directly from the harness to bypass inertia switch, still no fuel pump. Used a test light, took the ground from batt and touched the paper clip still at harness and the light lit just fine. Use multimeter and had 11.33 volt at inertia harness connector.

What can I do from here. What wire that inertia wire output goes? Does it go straight to the fuel pump?

Thanks again !

Dan

Tiny
Dannyr2009
Apr 19, 2010.
Two things, without the pressure test, no way to tell if the pump is tired, and could also be the ignition switch.
When it wont start give the bottom of the tank a whack upwards, if the pump starts, it shot.

Merlin2021
Apr 21, 2010.
I've tried exchanging the ignition switch and same issu. So it's not the ignition switch. Gotta be the fuel pump.

From here I would need to drop that tank and look if I have voltage to the fuel pump terminal but i'm scared to play with the tank itself.I am afraid to make a spark or something and explode in my face : )

Now the car won't start at all, even not used all night long and it's like 0 celcius outside. So I ask my dad if he can pull me to the garage with is truck, yesterday.

Tonight I will know more what's up with the car, I will tell you guys what's the issu exactly.

Thanks !

Danny

Tiny
Dannyr2009
Apr 21, 2010.
OK I'll check back.

Merlin2021
Apr 21, 2010.
It was indeed the fuel pump. Now the pump has been changed and the car works flawlessly. So if you have changed your fuelpump no more than 2 years ago and got about 30 000 km on it and onced started, the car works well but when hot, can't be started ( no primed, no gas). It can still be the pump itself.

I've wasted to much time trying to figure out what's going on when you turn the key instead of using the tools that the car had for me to diagnose the issu. (EEC connector - fuel pump tester lead) with ground.

I should of insert the paperclip in the eec connector and ground it and listen if pump work, if not, check if power was at inertia switch, if power is there, great chance the fuel pump is bad.

I've changed the ecu and ccrm for nothing. I was too sure the fuel pump was good. I thought it was linked to electronic equipement.

Oh well. Lesson learned!

THanks for your time and help.

Appreciated,

Danny

Tiny
Dannyr2009
Apr 22, 2010.
Your welcome Dan!

Merlin2021
Apr 23, 2010.
Hi again guys,

I had no problem until now, fuel pump is dead again. I got installed a good quality fuel pump, Airtex Master/Fuel Pump E2065, 1 year and 4 month ago. The pump is warranty for 1 year. So I will need to get it changed again. Ford fuel pump at deal worth 460, that's alot for a 93 ford tempo car, isn't it?

I ask to have installed the best Napa can grab. It most expensive one is 150$. I'll give another try and hope this time the pump will last longer.

Later guys,

Danny

ps: Is this common that remanufactured fuel pump didn't last long? 1 year, 2 year only?

Tiny
Dannyr2009
Aug 14, 2011.
Airtex should last longer than that. My 97 Tempo had an inspection plate in the bottom of the trunk (boot) that I could remove to gain access to the in-tank pump and wiring. With the key on, check to see how much voltage the pump is receiving. If possible, check resistance on the power and ground leads. They should be as close to 0 Ohms as possible. Excess resistance will decrease the voltage and current to the pump, which can cause it to malfunction.

Rivermikerat
Sep 29, 2011.