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Fuel filter in carbuerator...

1K views 11 replies 2 participants last post by  The_Sandman_454 
#1 ·
I was wondering if anyone has put an inline fuel filter before the fuel pump. I hate the one that goes in the carbuerator... I don't want to mess with trying to remove the metal fuel line and filter holder thingee... The original person who had the truck started stripping the little nut on the fuel line, and every filter change it got worse and worse, I don't like making new hard lines, so I figure after I get it back in there without a filter this time, I'll just put one in the rubber line before the mechanical fuel pump... Anyone see any problems with this?

Tim
"The_Sandman_454"

/wwwthreads_images/icons/cool.gif '79 Suburban 4x4 454, 6" lift, 35x12.5s & '85 GMC S15 4x4
 
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#2 ·
problem,no problem at all. In fact it works great. I had that same setup on my
toyota. I just cut the fuel line by the fire wall and using hose clamps put in
a inline filter w/metal ends and a clear glass tube so I could see the filter
element(fine mesh sceen).I believe it was a puralator from Discount A.P.for about
15bucks, they also had replacement elements(always had 3-4 in the glove box
If the truck started running like crap I just popped the hood and at a glance knew
if that was my prob. Because the body was made of glass I put a 4" piece of 1" hose
over it for protection from rock and such.anyway I liked it

HAWG WILD
ALL THOSE WHO WANDER ARE NOT NECESSARLY LOST /wwwthreads_images/icons/cool.gif
 
G
#3 ·
I've heard of people putting as many as three fuel filters along the fuel line (both before and after the gas pump). This was to remedy rusty gas tank problems, though, but it seemed to work fine. Point being, yes filters can go before the fuel pump. Also, I don't think the fuel is pressurized before the mechanical pump, so you might need to put in a filter similar to those used for non-fuel-injected carbs. I'm not sure on this though, so check. Also, one possible problem would be if your pump ever wore out and started pumping worn out pieces through the fuel lines, there would be nothing to stop the shrapnel from going into the carb. Just my 2 cents.

/wwwthreads_images/icons/cool.gif Steven Fairchild /wwwthreads_images/icons/cool.gif
/wwwthreads_images/icons/wink.gif 96' S-10 4x4 /wwwthreads_images/icons/wink.gif
 
#5 ·
Hmmmm.. I'm not sure what the problem is, I'm about positive it's not rust.. I just wanted something so I don't have to mess with the fittings on the carb because I don't feel like messin' with replacing it... /wwwthreads_images/icons/crazy.gif It's a new pump, so I think it should be ok, for a while at least... I'm thinking I'm going to try and find a way to put it after the fuel pump though... Thanks for the suggestions...

Tim
"The_Sandman_454"

/wwwthreads_images/icons/cool.gif '79 Suburban 4x4 454, 6" lift, 35x12.5s & '85 GMC S15 4x4
 
#6 ·
Hey Tim,
Are you speaking about the 454 or the 2.8? I don't think the mechanical pump in the 2.8 can't develop sufficient suction pressure with a restrictive inline filter on the suction side.

I know that auto parts stores carry kits to repair the bad threads for the fuel inlet nut/ carburetor.

xjy173 /wwwthreads_images/icons/smile.gif
 
G
#7 ·
just another thought(man it hurts when I do that) the first
thing most 1/4mile guys do is go to an inline because
the one in the carb is real restrictive. A lot of play'n in
the sand will crud up a filter fast(thats why I did it), sand
dust gets in place you can't even imagine. I just like the
clear one cause you can do a visual and there next to no
restriction(while clean)because it uses mesh not a paper
element.

HAWG WILD
ALL THOSE WHO WANDER ARE NOT NECESSARLY LOST /wwwthreads_images/icons/cool.gif
 
#8 ·
That's a good point about it in the suction side... I'm probably going to put it in the discharge from the pump... (yeah, this is on the 2.8L, I have an electric pump on the 454, and a filter up near the motor, and one before or after the pump, can't remember which, I think the suction side, but not totally sure on that)... I'll probably get a clear filter thingee so I can see what kind of condition it is in.. The one I took out of the carb was pretty full of gunk and other funky words.. /wwwthreads_images/icons/wink.gif I have a spare hard line for it, but it's going to be a pain to take it out of the parts truck and throw it in, but I probably will... I'm also considering re-routing the fuel line, perhaps a bit, but not sure on that... I'm going to re-do it anyway, in the warm weather when project "Anti-Fed" (in which the 50% that hasn't been removed by previous owner gets removed) gets worked on... /wwwthreads_images/icons/crazy.gif

Tim
"The_Sandman_454"

/wwwthreads_images/icons/cool.gif '79 Suburban 4x4 454, 6" lift, 35x12.5s & '85 GMC S15 4x4
 
#9 ·
Tim,
I reread your original post and I'm guessing that that previous owner used pliers or something similar to remove the nut and rounded off the flats. I thought you were talking about the fine threads in the carb housing itself.

There isn't much you can do about that, short of replacing the nut and tubing like you said. The mechanical pump should be able to push fuel thru the in line in the discharge line ok though. Good Luck!!/wwwthreads_images/icons/smile.gif
 
G
#10 ·
$.02
Placing a filter before the pump can (not will) cause vapor lock because of the fact that the larger volume of the filter WILL cause a pressure drop(P=V*T). Generally only a problem in summer and/or at altitude.
If there is garbage from the tank, best to clean/replace.
Dan

 
#11 ·
Yeah, I definitely should have thought of that... All last semester I got to learn about pumps, pressure, and all that other good stuff (this semester we get to run a lot of labs and stuff) /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif... /wwwthreads_images/icons/crazy.gif The thing that made me want to put the filter suction side is the convenient rubber line and already cut hard line... /wwwthreads_images/icons/crazy.gif I simply didn't want to screw around with the tubing cutter, and trying to rig it in there... /wwwthreads_images/icons/crazy.gif

Tim
"The_Sandman_454"

/wwwthreads_images/icons/cool.gif '79 Suburban 4x4 454, 6" lift, 35x12.5s & '85 GMC S15 4x4
 
#12 ·
UPDATE:

The truck is running again!!! Thanks to all who offered opinions! I had replaced the old (weak) fuel pump with a new one, but didn't change the filter in the carb at first. It wouldn't run for $h!t... Since the hex part of the fuel line nut was stripped, I wandered into the back yard, took the fuel line off the parts truck, fortuneately they were the same style, as I figured they would be... I cut the line right before it started bending around the front of the engine, and put a rubber fuel hose on. For the fuel pump side, I cut it after it about 3 or 4 inches above the fuel pump... I attatched the rubber line there as well.. Then, in the middle of that, I installed a clear fuel filter thingee. It was made by Purolator. I got the 5/16" one, because that's the size of the regular metal line, or it's close to that size...

Yesterday, I got it fired up, warmed up a bit, and took it for a ride around the back yard (in about 6" of snow), and after a lap or so around, I had it in 3rd gear, in 4low, and the engine died on me, and didn't want to stay running... I didn't have time to mess with it, so I let it sit there until today. I played around with the idle mixture on the carb, and sure enough, it now stays running... I had to have it open so far before due, I think, to a combination of a farily dirty/maybe plugged fuel filter, and a weak fuel pump, and with new filter and pump, it was causing it to flood out... Those Cooper STT's on there rock in the snow... I'd have probably been stuck in that little bit of snow with my old street type tires... /wwwthreads_images/icons/wink.gif But anyway, thanks again for the opinions, everybody! /wwwthreads_images/icons/wink.gif /wwwthreads_images/icons/cool.gif

Tim
"The_Sandman_454"

/wwwthreads_images/icons/cool.gif '79 Suburban 4x4 454, 6" lift, 35x12.5s & '85 GMC S15 4x4
 
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