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Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 35599
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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98 F150: good fuel pump relay..truck wont start..jumper

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98 F150, verified good fuel pump relay, and jumpering cross relay runs new fuel pump. No power to energise relay, and truck won't start w/jumper. Help please
Hello and Welcome to Justanswer,

My name is XXXXX XXXXX I am here to try and assist your with your question.

Can you tell me what wires at the relay you are jumping to get the pump to run?
Customer: replied 5 years ago.
green /yellow and green/orange I believe Ron, ts raining here now. Straight across the relay, and it does turn the fuel pump on. The red has no volt.
The red wire to the fuel pump relay is powered up by the PCM (computrer) relay and there are 2 fuses you need to check first, they are the #16 in the under dash panel and the #24 in the under hood panel. Take a look at the enclosed diagram and you can follow the power flow.

Customer: replied 5 years ago.
I will recheck, but all fuses are good. I have chkd all several times. I will recheck.

The red wire to the fuel pump relay comes from the EEC relay and if you are sure the EEC relay has power to it and none coming out then its bad. Double check it for me .

Customer: replied 5 years ago.
Sorry Ron, which is the EEC relay, I nbeed to verify power to there?
The EEC relay is in the under hood panel just like the fuel panel

Customer: replied 5 years ago.
Only Yellow/black has power, others same as fuel relay. I actually used this relay and horn relay to swap out for fuel relay.
Ok the white light / blue need to be hot as well. That wire is supplied by the #16 fuse in the junction bot, are you sure its not blown.
Customer: replied 5 years ago.
#16 is a 40A maxi, and my light shows good.
No, the fuse come from the Interior fuse panel #16

Also check the #9 in the under hood panel.

Customer: replied 5 years ago.
sorry, let me check., 20a mini, not blown, no power at all???
Ok, also take a look at the #22 fuse in the under hood panel.
Customer: replied 5 years ago.
Both of those fuses havepower and are good Ron.
You need power on the white/lite blue wire at the EEC realy, try overlaying a new power wire and see if it starts,, if so then your open in your circuit from the fuse to relay.
Customer: replied 5 years ago.
Ron, can I jumper from hot on that relay to white Lt blue? or do I need relay in place w/adde hot wire to Lt blue term?
It is a key source but to test it use the battery.
Customer: replied 5 years ago.
White/ lt blue is top socket, jumpered to 12v, relay out, did not start, fuel pump did not tutn on?
The relay has to be in place, you need to come in from the back side .
Customer: replied 5 years ago.
K, Take me a few.......
Let me know
Customer: replied 5 years ago.
done, same as before, didn't start and fuel pump did not energize. relays not making any noise. came off battery.
Ok, you told me every wire was hot except the red wire on the Fuel pump relay , was that correct?
Customer: replied 5 years ago.
the only wires that are hot are the full time hot wires on both relays. no other power on either, and inside fuse 22 does not have power, but it is good.
Which relay are we talking about?
Are you checking the relay with the Key on
Customer: replied 5 years ago.
ok, with jmpr in place, on eem, all but blk(gnd?) hot, on fuel pump relay, all but green/yellow hot. so appears relays working w/jmpr, but no start?
There is no black wire on the Fuel pump realy. See the enclosed diagram. All the wires should be hot on it cranking beside the Orange/light blue wire. are they

Customer: replied 5 years ago.
green/yellow not hot on fuel relay, blck on eec not hot. We did hear the Fuel pump cycle this time.
The black wire on the EEC relay is a ground and not suppose to be hot. If the pump is cycling it shoud start and run.
Customer: replied 5 years ago.
The fuel pump only cycles when I put my light on blue orange, but will not start???? Tried several times.
The blue/orange is the PCM ground and if it runs with the light on it that means the PCM isnt grounding it. Try running a ground to it and see if the pump runs while cranking.
Customer: replied 5 years ago.
ran jmpr, fuel pump running, but won't start.??????
Then in most case that means the PCM has failed.
Customer: replied 5 years ago.
Ron, will a code scanner verify that??? I will try and borrow one if it will help me?? And thank you for all your trbl!!! Don't mind spending the money for the PCM, as long as thats it!
A scan tool will not help . If you have doubts you may want to seek a second opinion.
Customer: replied 5 years ago.
You're the expert, I'm not doubting, just hoping. that will fix. Will my #22 fuse be hot w/new PCM?

The #22 fuse needs to be hot in the under hood panel.

Customer: replied 5 years ago.
I'm sorry, I meant the #16 fuse in the interior fuse panel. I'm 58, so if i don't write it down I get mixed up. I had a similar prob on my amigo, caused by alt. able to jmpr around it. But not here. If all that's left is to replace ecm, guess I'll give it a vtry! Thanks for your guidance Sir!!!
No the #16 fuse isnt a problem. The #22 needs to be hot.
Ron and other Ford Specialists are ready to help you
Customer: replied 5 years ago.
yes sir # XXXXX is hot, just rechecked. Thanks for trying!!! Give me somewhere to star tomrrow!! Have a great evening.
Im here tomarrow if you need me. Let me know.