[Scobi64]

1988 Ford F250 7.3 IDI
Absolutely in love with the truck. Trying my best to learn about these trucks and get mine back to where it should be since the previous owner(s) didn't care about it at all. Anyways, changed the valve cover gaskets today and in the process to make my life easier, also changed the fuel filter. Went from the Napa 3217 to the equivalent Autozone filter. Truck runs a hell of a lot smoother, and judging by the looks, it hadn't been changed in years. But now the fuel filter light comes on when I'm into the throttle, I'd say when I'm above 2500RPM. Any ideas?

 

[Scobi64]

Also, I definitely did let air get into it at first and ended up having to start it with a little starting fluid.

 

[chuckster57]

Welcome to the Diesel Stop.

The light comes on when there is a restriction. I bet your new filter has picked up a bunch of trash.

 

[Scobi64]

Welcome to the Diesel Stop.

The light comes on when there is a restriction. I bet your new filter has picked up a bunch of trash.

Thanks for the welcome.
Already? That would suck. Should I run some diesel kleen through it or change the filter again?

 

[chuckster57]

Depends on how much junk is in the tank(s). When I bought my truck I put a new filter on it.. three days later on a long drive I used a tank and a half, caused my filter light to come on. Changed the filter again and found sand and metal shavings in the old filter. Never have seen the light again, and I use Diesel Kleen in every tank.

 

[Scobi64]

Seems like a lot and semi expensive to run diesel kleen in every tank. I guess I'll change the filter again.

 

[chuckster57]

I only add the recommended amount- about 1/4 cup to 20 gallons IIRC.

 

[Bill1013]

When the filter lite comes ON, the IP is pulling a vacuum on the filter element. That indicates a plugged filter The fitting to the far left is the vacuum switch.

 

[Shawn MacAnanny]

I'm not sure about exactly when that sensor comes on, but couldnt it also indicate that the lift pump has failed leaving the filter in a vacuum state? Does it the light make a difference if you switch tanks? I would think you would notice a substantial decrease in power if the filter were that plugged. Or could the wiring been damaged? (i'm not sure if it's an NC or NO switch)

 

[Scobi64]

I don't notice a loss in power at all really. Like I said, it was only after the filter change. I'll run some kleen through her and then change the filter again and check the wiring. Any advice on how to NOT get air into the system when doing a filter change? I know to fill the new filter with new fuel.

 

[Scobi64]

I'll also check and see what she does when switched to the other tank

 

[oldrebuiltdodge]

Shawn, at or above 2500 rpm. if the lift pump were failing, the engine would most likely start missing along with the light coming on. I've had lift pumps fail and the engine keep running. Never turned on the filter light. I also can't swear that the light worked either, but there most definitely isn't any power, and feels like it is starving. I've also had the filter light come on at high rpm, you don't notice anything till you let it stay there for a while. Back right out of it, and everything is fine till you demand enough fuel again. I'd definitely replace the fuel filter.

 

[Scobi64]

What a pain in the ass to have to replace it again already. So when I do this time and it doesn't start, what do I use to help it? I'd rather not use starting fluid again cause I know it's not good for it. I've heard WD40?

One more question, should I use diesel kleen or clear diesel for this particular instance? Since it's geared towards this issue

 

[chuckster57]

Warm engine. Fill the filter with fuel or additive, I use SeaFoam, and it should start easily.

 

[LMJD]

What a pain in the ass to have to replace it again already. So when I do this time and it doesn't start, what do I use to help it? I'd rather not use starting fluid again cause I know it's not good for it. I've heard WD40?
One more question, should I use diesel kleen or clear diesel for this particular instance? Since it's geared towards this issue

It's possible you got a tank full of algae. If you're not aware, algae WILL grow in diesel fuel under certain conditions. I got a tank full right after fueling up at a truck stop years ago. Diesel Clean has no effect on algae. Cut your old filter open, spread the pleats and with a dull knife, scrap on the pleat's dirty side and if you have a slightly gooey, slightly brownish film, that's algae buildup. The cure is to buy an algaecide from a truck parts house and another filter or two.
"Any advice on how to NOT get air into the system when doing a filter change?"
If you fuel system's in decent shape, just fill the filter with clean fuel and it should start quickly like normal.

 

[Scobi64]

Thanks for all the advice everyone.