Blinking Fuel Filter Light

[screwhead]

Howdy, hope everyone is running well.

Made it to Oregon from Texas, pick up ran really besides vacuum pump going out in Nevada and then until two hours away from my destination. Kept Egts below 800-900 the whole way usually around 500-600. Have recently installed baby moose injection pump, injectors are less than 8 months old, new lift pump, brand new return caps, diesel leak free.

About two hours away I was going up a short (compared to the long upward grades pick up had just soared through) but pretty steep hill. At the top of it my fuel filter light came on and just after it did I had absolutely no throttle response. Engine did not die just went to a smooth idle. Fuel filter light stayed on steadily. I pulled over, cut the engine off, put a new filter on, it started right up barely had to bleed air out of the system and throttle response was back.

As I kept driving the filter light would come on when shifting (manual transmission) and when coming to stops. Usually blinking. I have read quite a bit of other posts of people having the same problem and it seems a lot of them have it after replacing all of the things I’ve replaced and seems some people fixed it by either replacing lift pump or the fuel filter sensor.

I am worried to start the pick up again if the lift pump is the problem and I’ve put hundreds of miles on the failing pump. I have a new sensor coming in tomorrow but wanted to ask y’all’s advice before I buy a new lift pump for it as well. Seems like a bad sensor wouldn’t make me lose all throttle response?

Also have the new vacuum pump on the way in and planning to rent a pulley puller from part store nearby.

 

[screwhead]

Also replaced both shower heads and cleaned out rear tank recently. Did the front tank something like a year ago.

 

[Clb]

There are numerous threads detailing lift pump issues, not counting the facett group buy in and its offspring.
However
And pertaining to you.
Is many guys forgetting to turn on the electric pump and running fine...( not often under towing loads tho.)
So if the suspect is the mach. Lift pump then you have isolated the rest. Eta
( details below but I suspect this)

Have you checked the fuel switching valve?
Look up old bulls tech 101.
Have you pulled the fuel tank caps off and back blew the lines respectively?

For the most part no throttle response is the wildcard here.
I had the faccett blues and the lamp would be on up any grade, headed to Alaska from Ca. It never got a no throttle response issue. It kept pulling but just acted pissy and mad me pissy.
Are you sure the power to the ip did not shut down temporarily?
Define "no throttle response: please

Put the trucks details in the / your signature line so we can see what we are working with.

Recapping
New ip and inj.
Fresh fuel filters 2 new showerheads with tanks at least 1/2 full ( yea You never said haha) you know the 1/4 tank issue?yes?
Good returns not sucking air(look this one up)...
No external fuel leaks.

Ok
New lift pump ...question
Who made it?
Chinamart may be bad part.
Ford oem last I heard was $$$but quality...

 

[screwhead]

@Clb I have a 93 7.3 idi na ZF5 transmission. Everything that I’ve replaced has been oem/stock equivalent besides baby moose injection pump. Got the lift pump from Napa I think it was made by Carter (?) can’t remember name of it. I have replaced fuel selector valve and it is working, not leaking. No lines that I can tell are rubbing or pinched. Do you mean I should see if that’s where I have some debris caught up/fuel restriction?

by throttle response I mean pushing the accelerator did absolutely nothing, peddle felt light and engine remained at a smooth idle the whole time I pulled over. I know there are threads related to this issue but I have not read anything yet where that happened especially right as the fuel filter light illuminated. I honestly thought that I snapped the cable till I opened the hood/started it again acceleration was back to normal and running smoothly.

I blew back the lines before I got to the farm I’m at now, with no compressor anymore. I’m aware of the issues with fuel running out with 1/4 of a tank left due to shower head collaspe, however I had close to 3/4th a tank before I drained it worried I got some bad diesel, diesel was free of debris and no water separation occurred after letting it sit. The tanks have already been cleaned and lines cleared before I got the new injection pump installed.

 

[Clb]

Ok sounds like you've got a good grasp of things...
Any chance there's an intermittent short to ip fuel valve solenoid not the idle up...
The front one iirc.
Cuz it sure sounds like zero fuel pressure.
When both my 7.3' ran dry the pedal felt useless as you described.

Trash in the lines is doubtful.
Lift pump ,maybe.
For grins fire it up and pull the fuel solenoid wire and see if it duplicates the issue.

 

[Austin86250]

When my lift pump when out I had no throttle response when up to speed

 

[Bart F-350]

@ Screwhead,
you still have the last fuel filter you changed?
I would suggest you open it up, and have a good look at the media.
I have had problems with the diesel pest, and I've written something about that here: https://www.oilburners.net/threads/...-could-be-the-cause.92063/page-4#post-1124462 and at post 49 I've posted some images of my fuel filter, on which the first glance you thought nothing wrong there, and then, at a second look you see that the whole media is covered with a though layer of goop, and to my idea that caused the vacuum sensor to fire your dashboard light, and caused the no response accelerator pedal. I think the next step after that might have been that your engine died on you (at least until you reinstated enough diesel fuel coming into the pump again.)
That was my case.
good luck to you, I hope you find the problem soon enough.

 

[hesutton]

That light is in response to low fuel pressure. Usually contaminated fuel clogging your filter quickly or a bad lift pump. You have a fuel pressure gauge? I run one in the cab on both my IDI's for this very reason.

Like suggested - cut open the old fuel filter and see how clogged the filter media is. IF that isn't the issue, check fuel pressure at the filter head.

Heath

 

[rreegg]

That light is in response to low fuel pressure. Usually contaminated fuel clogging your filter quickly or a bad lift pump. You have a fuel pressure gauge? I run one in the cab on both my IDI's for this very reason.

Like suggested - cut open the old fuel filter and see how clogged the filter media is. IF that isn't the issue, check fuel pressure at the filter head.

Heath

Is there a specific range of fuel pressure you're looking for or just have one to be aware of big changes like an idiot light? Mostly just curious what pressure range the fuel is at though

 

[Bart F-350]

I see coming back every time; at the schrader valve 5 Psi.