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sputter/bucking under load

I wouldnt be comfortable using the same stock fuel filter/water separator for more than a year. Even if its not dirty could it lose some filtering ability, or water separation capability?
 
With the type of filter that it is it should filter better as it gets fuller just reducing the amount of flow. Never had a water problem in the 7 years I've owned this truck or in the 6.2 we use for a plow truck for about 20 years. It rains a fair amount here also. Also their pretty serious here about gelling and I can't say I've ever had a gelling problem either. I did see the fuel pumps freeze up at -22 the first year of ulsd. Even that's been cured.
 
I'm not sure what a Walbro or Racor is or a filter manager, I'm assuming some sort of specialized aftermarket filter? I'm only really concerned with the lift pump, I checked it today, key on/engine off and it was making a throbbing noise/felt more than heard, didn't feel right. Almost like a very muffled clicking. What's it supposed to sound/feel like? I was expecting more of a steady buzz.
 
Detroit Dan said:
I'm not sure what a Walbro or Racor is or a filter manager, I'm assuming some sort of specialized aftermarket filter? I'm only really concerned with the lift pump, I checked it today, key on/engine off and it was making a throbbing noise/felt more than heard, didn't feel right. Almost like a very muffled clicking. What's it supposed to sound/feel like? I was expecting more of a steady buzz.
Click to expand...

A walbro FRB5 is a lift pump that can replace the factory LP. It is a better LP that can handle sending the right amount of fuel all the time, including while towing heavy. Racor is a filter that some people are using that you would want to place in front of the walbro LP to help keep it protected. If you do use or try this system it is recommended to keep the factory(filter manager) in place as a secondary back up filter. This helps guarantee to keep all the drud out of the injectors.

If your LP is making noise than it is working its way to a death. They only last so long. If you do decide to go back to the factory LP than get a 1993 model LP that is a AC Delco brand. They pump better and longer! ):h

They have a test for the LP, I will see if I can find it for you and post a link!

Lift Pump Test here!
 
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I had the sputtering / bucking thing start last week, thought it was
the filter, turned out to be the LP - O'Reillys auto parts had one for
90 bucks, called the dealer, they wanted 660.00 - guess which one I got
 
My 2 cents.
I had very simular conditions. Bucking under a load. I replaced filter and still had problem, the LP was new just a month old at the time. The problem turned out to be that the line between the LP and FM was almost totaly pluged. I blew it out with air. You might want to do that also while your LP is off. Takes about 10 minutes Just disconnect the rubber hose going to back of the FM and the line coming from the LP. I slid a hose over the line at the LP and directed it toward a bucket. Then just hit it with the air on the FM side. Use a clean bucket so you can tell if anything comes out.
You can also blow air from the LP back to the tank. Make sure fuel cap is off before blowing air to tank.
 
Burning oil said:
My 2 cents.
I had very simular conditions. Bucking under a load. I replaced filter and still had problem, the LP was new just a month old at the time. The problem turned out to be that the line between the LP and FM was almost totaly pluged. I blew it out with air. You might want to do that also while your LP is off. Takes about 10 minutes Just disconnect the rubber hose going to back of the FM and the line coming from the LP. I slid a hose over the line at the LP and directed it toward a bucket. Then just hit it with the air on the FM side. Use a clean bucket so you can tell if anything comes out.
You can also blow air from the LP back to the tank. Make sure fuel cap is off before blowing air to tank.
Click to expand...

Think it would hurt the lines to spray carb cleaner in the lines before blowing air through them? FM - LP line is the one i'm referring to.
 
Matt Bachand said:
Think it would hurt the lines to spray carb cleaner in the lines before blowing air through them? FM - LP line is the one i'm referring to.
Click to expand...

Not at all, just make sure to blow enough air through the line to dry out the carb cleaner. You would'int want it getting to the engine.
 
OK, all I can find locally is the cheap Airtex pump, going to have to be good enough for now I hope. I did look up both the 97 and the 93, they are a different part number (and the 93 is much cheaper), so apparently there really is a difference. So I should go with the 93 right? It all fits up the same? I'm going to blow out the lines at the same time.
 
When I used the 93 lift pump I had to switch the plug out. The male female were reversed. Not a big deal. I'm not sure what years of vehicles this is an issue on.

Also after I blow lines I try to get some Marvel or Sea Foam into them and blow them again. Or at least diesel fuel.
 
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