Thank you Sir! Timely and helpful advice as now having tested pressure in the fuel rail–none–I turn now to circuit testing. Your comment re: how due to design/build on this SUV, fprelay bypass might damage or blow other curcuits/components–I have wondered if that might be the case here: My crude bypass rig worked fine for over a year until everything stopped suddenly in mid-crank. Car cranked over promptly as it normally does but instantaneously shut down just as the engine began firing. And I did detect a clicking noise emitting from the fuse box vicinity…no idea then or now what that could mean, or not. In any event: your comment is on point. Very helpful, as are all the comments coming in from all respondants to my Car Talk posting. I’m very green in this task of tracking down and diagnosing the problem. Definitely learning about the downsides of my cheap bypass. Thanks all!
OK, thanks. The link on testing a relay is timely. I by passed the relay a year ago, but I’ll check all connections. Thus makes me wonder if the click might have come from a different relay/circuit. Thanks again!
Hello any and all who may have tuned into and/or commented on my newbie shadetree efforts to get my '03 Ford 5.4L Expedition back on the road…
Herein I can only just list what I know by now and what I’ve done to diagnose…any comments, immediately helpful or even remotely helpful…much appreciated!
Status: No fuel pressure in the fuel rail.
- With key on, I hear the whirring of what I’ve assumed was the fuel pump priming the motor for start up.
If I disconnect my jackleg fuel pump relay and restore the original connection, at “key on” I still hear the whirring a few seconds before it dies.
However, the motor then does crank strongly but barely fires or fires not at all. No rail pressure at all.
- If I reconnect the single wire fuel relay by-pass rig that has worked fine for at least a year before the car again started the crank, fire but not run problem again–
–with that by pass once again in place, I still get the whirring but still no rail pressure…
However, this much is different: With my by pass in place, the 5.4L engine cranks, fires and will run a very short while before it dies. Engine even responds to foot acceleration–revs up, spits and sputters a bit then dies. It will keep doing this as many times as I crank it. So it must be getting SOME fuel to the rail and injectors, but it won’t keep running. Dies. Still no fuel pressure at the rail, at key on, and no rail pressure either after the short sputtering fire-up at each crank
This seems to indicate that:
–the fuel pump is sending a little fuel forward sufficient to start and briefly run the engine but it can’t sustain flow,
–there may be some blockage in the fuel pump or lines forward of it. ( Fuel filter is brand new)
–maybe some problem with the fuel pump driver or driver relay? (So far, I have not done ANYTHING to test any driver function. I don’t know enough about the “fuel pump driver”-- not the location, not the relay for that diagnostic step yet. )
I can hear clicking at the fuse box array at “key on,” but I have to assume it’s just other relays and NOT the fuel pump relay.
That’s it for a summary of function status.
- Here some readings I’m getting on my multi-meter when I check the DISCONNECTED five prong connection just above the fuse box:
-
All readings below derive from the connector plug unplugged, with readings then taken at the verified correct slot on the loose plug and also readings taken at the appropriate pin at the 5 pin connector plug slot above the fuse box:
-
At the loose plug, all below at “key on”:
–confirm continuity at yellow position with audible tone. Digital meter displays a 10 or 11
–8 ohms when dialed to 200 on the ohm section
–.01 volts registered with meter dial at 20
–3.7 amps registering when dialed to 200m
–registering .85 amp when dial at 20m
So I infer that this these meter readings show entire extent of power coming through the plug and INTO the the junction point and then into to the fuse box relay, which apparently is kaput.
- Readings taken “key on” at the correct pin at the five pin connection slot leading to the relay, with plug not in the slot
–6.5 volts
–2.5 amps
–no continuity
–no ohms
OK, that’s my status at present.
Any comments definite or merely suggestive–all welcome.
I feel like it must just time to quit delaying and to go ahead, bite the bullet and pull the fuel pump 
.
Any other apparent diagnostic indications from multi-meter? I’m pretty clueless at what I’m getting so far. (And I can only assume/guess that there is some capacitor feeding some power back up to the empty plug slot above the fuse box?)
–Any recommendations for other checks to any other relevant relays–or to the fuse box driver itself or that relay?
OK, thanks to any and all who waded through the above message!
You have to find out what the fuel pressure is before you continue.
Tester
OK thanks! Gas in the tank verified.
The problem may well derive from bad gas.
Problem first showed up after apparently getting bad gas, perhaps from the rural station supply tanks drained way down near to bottom of tank.
Problem again this time showed up after getting cheap gas from the same station–which I’ve mostly avoided until recently.
Your advice to pull and examine inflow at the filter itself–on point, much appreciated!
Are there any other multi-meter diagnostic checks I should try before pulling the fuel pump out of the car tank?
Definitely will follow you advice on how to check the fuel pump inlet on a clean towel surface.
New question before I pull the fuel pump: The fuel pump still turns on at “key on” and can apparently pump SOME gas to the fuel rail, enough to run combustion for very short time before the motor gets starved and dies. I can do this over and over, same result. So hopefully the fuel is only clogged and can be restored to full function. But once I get it out of the Ford Ex tank, how do I then check to see if it’s fully functioning again before I re-install it in the car. Given the age of the car, makes more sense just to replace the fuel pump. But that might not be possible at the present time. Thanks again for your helpful advice on this issue!
Before you do anything else install a pressure gaige and see what, if any, the fuel pressure is at the fuel rail.
That should have been step 1.
Hi. Thanks!
Already verified: no pressure at fuel rail, at “key on” and still no pressure at the rail even after a quick start and sputtering short time run
When you turn the key on, the fuel pump runs for a second or two to build the proper fuel pressure and then turns off.
If the fuel pump runs but doesn’t produce fuel pressure, the fuel pump is shot.
Tester
Thank you! Very helpful. I’d wondered if that might be the situation.
I should have gone ahead and pulled the fuel pump at the get-go.
But I’ve avoided it thus far because for me that has seemed a pretty big job.
I don’t have a lift so I have to elevate the Ex to sit solidly on 6×6 blocks on the ground. I don’t trust standard metal supports because they dig down too irregularly into the “floor” of my shadetree workspace.
No matter. I’ll start that task tomorrow weather permitting.
Thanks again!
Seeking advice: How to loosen the band that secures the gas filler hose at the tank.
By now I have finally gotten all four of the tank supply and return lines freed of the cheap plastic “adult proof” connector toys, fore and aft.
BUT! I can’t free up the gas filler hose proximal to the tank because the screw or nut that tightens the clamp/band-- whichever it may be–because they’ve got the band positioned such that I can’t even see the adjustment screw, much less access it in order to loosen it!
Can anyone shed some light here?
Doesn’t appear that I can just cut the hose and then replace because I can’t get to the upper side of the filler hose!
Thanks again for any guidance here to get me going forward again. I’ve been up and down and all around with this fuel pump nightmare–by now I’m close to lowering the tank but there’s this one last holdup!
The clamp will have be to cut off.
Tester
Disconnect the entire filler neck assembly from the car at the upper end and lower it along with the tank.
Finally got tank disconnected. Pulling it today.
Here’s my tenderfoot shadetree plan going forward:
-
Remove tank
-
Pull pump
-
Check screen and clean if possible
-
Return and secure pump into tank
-
- Test pump prior to any re-install by similar fuel pump by pass as previously used.
-
Advice on testing much appreciated!
–How do so safely using relay by pass? Previously when I by passed relay, I just ran a single power cord from + terminal at
battery to the correct insert on the plug above the fuse box, unplugged.
Thus, question now: how safely ground the connection to the fuel pump after I reinstall pump into the fuel tank for testing PRIOR to re-install of tank into car? Tank out of the car.
Background context for testing pump prior to re-install or replacement: After fuel pump failed and was no longer pumping gas to the rail, fuel pump was nevertheless audibly whirring at “key on.”
If after I clean current fuel pump of rust, debris etc., will it make a different sound that would indicate the pump is still viable for re-install into the car?
Given the age of car–probably original fuel pump–should I just go ahead and buy new pump (finances ARE an issue)?
Suggested cheaper-end reliable replacement pumps? Auto-Zone I usually deal with had a True-Grade at $277. (plus I get 20% discount)
Any alternative recommendations for replacement pump?
- Lastly: I can’t replace fuel pump relay yet so I’ll re-rerun the bypass after tank goes back into car.
I did not run a fused power wire connection on previous by pass. Stupid, yes. I think that might be possible reason fuel pump quit fully functioning.
Any advice there?
Thanks in advance for any and all advice here on any of this!!!
Instead of jumping from the battery + to the relay socket, jump across the relay socket itself.
Now the fuel pump will run each time the ignition switch is turned to on.
Tester
Thanks. If I’m correct in assuming you’re advising a jump between pins in the relay socket above the fuse box on rightside kickboard…that fused relay was by passed a year ago. Does not function. Hence the direct connection to the battery. Maybe I’m mis-understanding?
Thanks.
Are you saying there’s no voltage to the relay socket for the secondary side of the relay?
Tester
You did all that work to look at the fuel pump. why not just replace it.
Even you can get it to work, the original fuel pump can die a month later and you will be taking everything apart again.
Copy. I’m thinking the same myself at this point! Thanks!
OK. Thanks, “Tester”!
That’s correct, no power from the relay at kickboard unless by pass in place. By pass from plug does activate fuel pump to prime (whir) but no fuel reaching the rail.
In this context: I’ve decided to heed prior advice from several respondents just to buy a new pump.
However, I’ll have to continue the by pass connection as I can’t replace $600 Ford fuse box yet.
So, now, any advice on the best, safest relay bypass much appreciated.
In earlier diagnostic efforts, with by pass in place, at “key on” the pump would prime but no pump to rail as noted above.
With bypass in place at key on, my code reader was throwing a “Pending” code P0232-Pump Secondary Circuit High.
This makes me think that maybe my jackleg bypass wire, unfused, was overloading the Secondary Circuit and maybe blew something out in that curcuit or just burned out the pump???
I do plan to make my bypass connection to the new pump FUSED.
Any advice there from any angle much appreciated!
Copy. Agreed!