Interesting lack of fuel problem - easy fix

[Philbilly]

I was out motoring last weekend. Took a 2 lane curvy hilly back roads trip about an hour to my destination. Stopped for a cold one and on the way back started having issues. When going up hills she started chugging like she was not getting gas. I have had my 1982 about 7 weeks and the PO did keep up with maintenance but I hadn't changed the fuel filter yet. Note, PO put a universal fuel filter before pump. The mechanic he used said he didn't understand why the wasn't one before the pump. Any who, got underneath and low and behold a bolt that holds the protective plate for the fuel pump was gone and hanging down. Rifled through my spare bolts drawer, replaced and my lack of fuel issue is gone. Apparently when I was going up hill the fuel pump slid back and crimped the fuel line. Needless to say was very happy for a zero dollar fix!

With that said, my fuel is dirty, dirty, dirty. Dirty is good for some things but not fuel. I was going to take out the extra fuel filter but I am leaving it in for now. I have added clean/refurbish fuel tank to the list. Not sure what method I am going to use yet. That will probably be a winter project...

[divace73]

I'm not sure if having a filter before the pump is a goog idea for the following reasons.
1. they were never designed to have a filter before the pump
2. should the filter get too blocked and restrict or stop fuel your pump will burn out, the fuel flowing through it keeps it cool.
My 2c worth (Excluding Australian GST)

[Michiganjfrog]

Yup filter after the pump, keep in mind that the electric pump recirculates a lot of fuel so it will essentailly cleanup any junk. As far as it getting dirty fast you may want to drop the tankk and have it pressure cleaned. Whatever it is coated with inside tends to disintegrate, you can always tell an old Fiat when its in the garage for too long. Good luck

[bradartigue]

The mechanic he used said he didn't understand why the wasn't one before the pump.

Where are you guys finding these "mechanics?" Bosch FI systems have fuel filters after the pump. Most of them now have the pumps submerged or semi-submerged directly into the tanks.

Your tank is rusty, have it cleaned and coated.

[fiat218]

why would u not want a fuel filter before the pump?
u would think u would want to stop dirt/rust/whatever before it goes thru the pump

[81SPIDERMATT]

fiat fuel pumps are great at pumping fuel not sucking fuel..... clean the tank if needed.....

i had fuel issues... po had a filter before the pump as a bandade to a dirty fuel tank.... killed the pump when it got clogged.... cleaned the tank .replaced the pump and the after pump filter.. and for a few days after i had a filter before the pump just to see if crap was still coming from the tank.... clear as a bell ... took it off and all is well

[spider2081]

Another thought
I took apart a Bosch fuel pump that would not run. I found the pump mechanism jammed with rust particles from the tank. After cleaning out the pump I reassembled the pump and powered it up. The motor was in great condition it ran fine, and I am convinced the failure was caused by the rust particles. I did not reinstall that pump on the car.
I emailed WIX filters and gave them the fuel pump info and car information asking if they have a filter that would work before the fuel pump. They suggested their filter 33248. I forget the micron size but its pretty big. The filter has 1/2 inch nipples and is in a metal can about 3 inches long. I installed one in my car and notice no change in acceleration.
I feel trying to protect an expensive fuel pump with a 7 dollar filter is worth the expense.
I believe other cars like some Alfa's use a filter before the Bosch fuel pumps. So its not an original idea.

[fiat218]

well that my thought, filter before the pump makes sense, not after / or have one before and after.

[4uall]

I am from the school of trial & error. If it works for you keep doing it , if not lesson learned

[bradartigue]

Fix it correctly. Remove the tank, have it cleaned, reinstall. Problem goes away.

You aren't saving your pump with a filter before it, you're kidding yourself. You're taking something engineered to work a certain way and, because you can't believe a filter will hurt, making it work another way. You're making a pump work harder than it should, and exposing it to a filter not designed to be drawn through at 45+ psi.

I bet few of you even run the right pump, but sure as hell when it fails it will be anything but your decision making process that was to blame.

Stop being lazy, fix it right.

[Divers]

Curious...Do modern cars have a filter pre or post the fuel pump?

[donm]

My 01 and 04 Saabs have a tank munted pump and a filter in the line to the engine.

[bradartigue]

Curious...Do modern cars have a filter pre or post the fuel pump?

Nope. Most modern cars have a fuel pump in the tank and a fuel pump outside of the tank. The former is low pressure, the latter is high pressure, although many just have a high pressure pump. It depends on the position of the main, high pressure, pump relative to the tank. High pressure pumps are lousy at pulling fuel; they depend on high volume and continuous flow. Some systems have a low pressure pump, an accumulator, and a high pressure pump, and others have an accumulator and a high pressure pump. Some have two main pumps and an accumulator. The accumulator keeps fuel from pulsing upon expulsion from the pump, and sometimes they are located in between the two pumps with a feed from fuel return as well.

What is being suggested here is to introduce a filter into a system that is already challenged by the cheap, basic design FIAT chose. L-Jetronic had a lot of options that could be used by manufacturers to improve fuel delivery and engine monitoring, FIAT chose none of them for the 124. Unlike the Alfas and Porsches and Mercedes and BMWs and Saabs that used L-Jetronic there is no strainer, no pre-pump, no accumulator. FIAT uses a pump only, and it is the most basic pump with an internal bypass and a single line. It is a basic design but it doesn't mean it isn't a good design.

Your filter is going to do one thing good and many things bad - the good is that it will serve as an accumulator to smooth out the natural tendency for pumps to create pulses of fuel. It will also hold some fuel in cars that develop (as many Spiders do) a tendency towards an underpressurized tank which pulls fuel back when you turn off the key. That's the good. Here's the bad: you're going to make that pump work hard and you are going to be adding a point of failure (actually several points of failure).

A filter will make your pump work harder. Period. You cannot buy a filter that allows for the same fuel delivery rate as having no filter. It is impossible. So you've added more work for the pump to do, and therefore have shortened its life. Will it be shorter than filling it with rust? No, of course not.

A filter requires creating a point of failure underneath the car. Clamps and cuts.

So in all of this you decide what to do. You can install that filter, and it will now fill with rust, and its useful life is relative to how much rust gets suck into it. The pump will work at incrementally more difficult loads until you replace the filter. And over and over and over and over.

Which leads me to my suggestion: you have RUST IN YOUR FUEL TANK. Fix the problem.

[Philbilly]

Great info on the fuel filter before pump issue. I will be taking mine out as soon as I get my gas tanked cleaned.

As for as tank cleaning goes I've seen guys/gals have taken it to a radiator shop, or DYI by using POR 15 sealer or something similar. But then I read there a baffles on the inside and that won't work well with that. And then others use ball bearings to knock rust off and clean. I guess there is also a new or refurbished but I'd rather not go that route.

I'm a little confused on which method to use.

[bradartigue]

Great info on the fuel filter before pump issue. I will be taking mine out as soon as I get my gas tanked cleaned.

As for as tank cleaning goes I've seen guys/gals have taken it to a radiator shop, or DYI by using POR 15 sealer or something similar. But then I read there a baffles on the inside and that won't work well with that. And then others use ball bearings to knock rust off and clean. I guess there is also a new or refurbished but I'd rather not go that route.

I'm a little confused on which method to use.

Take it out and have it professionally done. Barring that the POR-15 stuff works fine if you keep moving the tank around so it can distribute evenly and coat all surfaces. I'll argue it is more important to make sure the top 1/2 is coated since it is the part that is usually not covered in gasoline (and therefore protected). The baffle, etc., are usually awash in fuel.