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Index > @ the Pickup Bed (General Topics) > Thread: opinions on fuel pump
Thread: opinions on fuel pump
wankel_dreams


Redlining
Posts: 293
posted March 10, 2002 05:30 PM

opinions on fuel pump

Truck has been off road for about a year now.......

Well, I powered on ignition the other day. Fuel pump sounds like its working, but no fuel flow. Thinking maybe there was air in it, I primed it using a vacuum pump on the fuel line to the carb until i had a good amount of fuel through.. still no flow, sound did change did change though when i primed it. So i'm thinking it may be bad. I haven't pulled it off the truck to test it yet, but suspect it is probably bad. 3 questions:

Any ideas as to why the pump sounds like its working, but not pumpin any fuel?

What is a good after market fuel pump to use? I'm currently running the stock carb, but would like to uprgrade in the future.

Is there any kind of drain plug on the fuel tank? My tank has been full of fuel (and not run) for about a year now. I'd like to drain it (lawnmower fuel...hahaha) and clean it.
How should i drain it?

Thanks
____________
74 wankel panther
77 REPU
79 rx7
89 Vert

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Jeff20B


Moderator
Posts: 661
posted March 11, 2002 12:20 AM

I'm not sure about a drain plug, but you could siphon it out of the fuel pump hose after you remove it. The stock fuel filter is in between the pump and the tank so you may want to remove it before siphoning. Just play around with the hoses a bit and you'll get it sucked out. Don't forget to get a new filter. The Fram G12 is what the book says to use and it's what I use.

I'm interested in a good fuel pump too. So who here has a good aftermarket pump, filter and pressure regulator? Mine is set to 5.5 right now as an experiment (stock is supposed to be 5.0).
____________
'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7

       
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wiredodger


Newbie
Posts: 1
posted March 11, 2002 08:42 PM

fuel pump

I had to walk home twice in 30 years becaucse of a bad fuel pump. Both times the pump still "runs", makes noise and shakes, but the little rubber one-way valves inside are wornout so the thing doesn't pump any fuel, the noise and vibration just distract you from the facts.Change the pump.

       
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Jeff20B


Moderator
Posts: 661
posted March 11, 2002 10:27 PM
Edited By: Jeff20B on 11 Mar 2002 22:28

Which side of the carb should the pressure regulator be? On most stock vehicles, it's on the return line so it won't be a bottle neck in the fuel delivery system. Even a carbed Fiat X1/9 is like this. So why does RB recommend installing a pres-reg as close to the carb as possible? (I assume they mean on the feed line, not the return line). Anybody know?
____________
'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7

       
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rotarynews


Moderator
Too Many Rotary Websites
Posts: 206
posted March 12, 2002 09:14 AM

ON the inlet side

I've put my regulator and pressure gauge on the inlet side. This way I can controll exactly how much fuel the carb gets.
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Jeff20B


Moderator
Posts: 661
posted March 12, 2002 10:40 AM

But what about the return line on a stock carb? I know the return line is smaller and is supposed to flow less. It probably wasn't designed to hold pressure though. But what about right near the carb? It would be a short run from the return nipple to the pres-reg. A small hose clamp instead of that stock hose 'wanabe' clamp should do the trick. I just don't like the thought of putting so many things in the fuel line. Hmm, maybe if the fuel pump has adequite (sp) volume, it won't matter.

This still doesn't answer the question of why some (if not all) auto manufacturers install fuel pressure regs on the return lines instead of the send lines.
____________
'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7

       
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wankel_dreams


Redlining
Posts: 293
posted March 12, 2002 04:58 PM

ok i yanked the fuel pump, and at first it seemed good, but upon further testing, wouldn't pump fluid any more than about a foot higher in elevation than the pump. So went and got a new universal fuel pump and some new fuel filters. Due to the mounting orientation of the new fuel pump, one of the fuel lines was too short. and i couldn't get to the other end of it to remove the clamp. Had to drop the fuel tank, which I had had been wanting to get cleaned anyway. The fuel line that was to short goes from the pump to a "dohickey" then another fuel line goes from the "dohickey" to the fuel hard-line to the front of the truck. what is this??? Is it a flow restrictor or pressure regulator of some sort? Can i bypass this "dohickey" and run straight from the pump to the fuel hard-line? I can take a digital pic tomorrow if my technical terminology isn't clear enough (dohickey)

On a second note, there was very little rust on the inside bottom of the fuel tank. I was surprised for a 25 year old truck that has sat for long periods. Gonna take it to a radiator shop tomorrow.

and a third note
quote:
A small hose clamp instead of that stock hose 'wanabe' clamp should do the trick.


I am putting in all new the fuel line hose and using standard hose clamps instead of the pain-in-the-arse stock ones.
____________
74 wankel panther
77 REPU
79 rx7
89 Vert

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repuguru


Redlining
Posts: 319
posted March 12, 2002 08:11 PM

Are you refering to the plumbing for the evaporative tank in your bed? Or does this line go foward?
____________
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for it.
85' GSL-SE
83' GSL

       
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Klaus43


Rotorhead
Posts: 1259
posted March 13, 2002 12:11 AM

Sure enough,pump diaphragms go bad over time, just like vacuum (secondary) diaphragms... guru sounds like he's on the 'dohickey' question... as for location of pressure regulators, my guess: on the return line makes sense to regulate the pressure of a pressurised TANK system... before the carb makes sense to control the pressure to the float bowl. I wouldn't screw with the return line...it's just there for the excess. What's the best pump? The one that works for your setup, without problems, for not too many $$$ !

       
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wankel_dreams


Redlining
Posts: 293
posted March 13, 2002 11:53 AM

quote:
Are you refering to the plumbing for the evaporative tank in your bed? Or does this line go foward?


no, i see where that is. this is between the fuel pump and the carburetor. here are some pics from the drivers side. in first pic u can see frame rail, my new fuel pump, and the "dohickey". second pic is a closeup.


____________
74 wankel panther
77 REPU
79 rx7
89 Vert

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Klaus43


Rotorhead
Posts: 1259
posted March 14, 2002 10:26 PM

...perhaps we should take a poll?...

What is this 'dohickey' thing, anyway?
1.) a really funky way to splice a fuel line
2.) a really chunky way to mount the fuel line
3.) an old-school Mazda factory pressure regulator
4.) an aftermarket part that doesn't belong on a REPU
5.) a part rendered meaningless by virtue of the option(s) that attach to it aren't there
6.) a worthless, useless emissions component that never worked to begin with--now dead weight needing removal
7.) a 'whatchamacallit' (designed to confuse those only familiar with 'dohickeys')
8.) the secret weapon for EXTRA POWER!
9.) a backflow prevention device (valve)
10.) a connecting block for fuel send & return lines--nevermind emissions connections

       
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wankel_dreams


Redlining
Posts: 293
posted March 16, 2002 08:10 AM

my vote is #7, and if not #7, then #9,

This is OE as the bracket its mounted on is factory welded to the frame. I just started thinking what it could be and figured either it was nothing, or a backflow preventer. obviously klaus did even more thinking than me. I left it in either way, but took out almost all the other "extra" fuel line plumbing. My fuel system is now totaly new/refurbished. Tried to start her for the first time last night (nighttime to disguise the smoke plume) and it was a no-go.

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nathanlipshin


1st Gear
Posts: 14
posted May 16, 2002 09:53 AM

Does your truck start and then die after a couple seconds or so? I think we may have the same problem. If you solved it can you tell me how

       
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Klaus43


Rotorhead
Posts: 1259
posted May 16, 2002 10:25 AM

Items to rule out:

Does it die the second after you let go of the ignition switch...? If so, there's the culprit...otherwise, besides making sure the fuel pump is working, however minimally, I'd want to make sure the line is clear from tank to carb, (filter included). If the carb can also be ruled out, more or less, a once-over of the rest of the ignition system might be in order... condition of plugs, wires, cap&rotor, (points???), timing... More likely, however: a vacuum leak.
Perhaps this in conjunction with other factors...how long has this REPU been sitting? If it is electrical, remember to clean up/provide a ground from motor to chassis...corrosion happens. And, even if everything else is O.K., it may require some gas pedal action until it's running enough to keep running on the choke... Good luck, & happy wankling! --Klaus

       
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Tom93R1


Redlining
Posts: 458
posted May 16, 2002 11:13 AM

quote:
What is this 'dohickey' thing, anyway?
1.) a really funky way to splice a fuel line
2.) a really chunky way to mount the fuel line
3.) an old-school Mazda factory pressure regulator
4.) an aftermarket part that doesn't belong on a REPU
5.) a part rendered meaningless by virtue of the option(s) that attach to it aren't there
6.) a worthless, useless emissions component that never worked to begin with--now dead weight needing removal
7.) a 'whatchamacallit' (designed to confuse those only familiar with 'dohickeys')
8.) the secret weapon for EXTRA POWER!
9.) a backflow prevention device (valve)
10.) a connecting block for fuel send & return lines--nevermind emissions connections


Hahaha, I can't believe I have never seen this post. You are a pretty funny guy.

My guess is none of the above. Perhaps it is something that the Ford Courrier uses. If not that then either #10 or #7


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rotarynews


Moderator
Too Many Rotary Websites
Posts: 206
posted May 16, 2002 11:32 AM

It maybe...

It maybe some sort of thingamagig that regulates the pressure...

It could be a fudgamaroo that you can tap in, and have a secondary fuel tank somewhere

It is possibly a cogerdoodie that simply holds the fuel lines in that position for the sake of holding fuel lines in that position.


Those are my guesses I'm standing the fudgamaroo idea tho.
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nathanlipshin


1st Gear
Posts: 14
posted May 16, 2002 11:49 AM

I am not 100% sure of what that thing would be called but I do know that it only lets fuel run one way, and it appears to be some kind of pressure builder becasue my fuel pump will not pump anything out unless it is attached to that thing. Or maybe my fuel pump is bad, I dont know.

       
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Uncle-Jim


Revvin Up
Posts: 64
posted May 16, 2002 01:06 PM

Do-Hickey

Someone was right earlier. That is a one-way gravity valve and is there to shut off gas flow if the truck turns over in an accident or is at an angle that would spill gas out of the carb on to a hot engine.
Newer cars have to do this, and disable the ign. so everything shuts down immediately.
____________
Uncle Jim
72 Rx-2 Show Car; '77 REPU (250K & goin' strong) 2 - '76 Cosmo's

       
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wankel_dreams


Redlining
Posts: 293
posted May 17, 2002 05:01 PM

FINALLY!!!!!!!!

Thanks Uncle Jim, now when i have the gas tank dropped again to work on the fuel level sender, i can eliminate this too.
____________
74 wankel panther
77 REPU
79 rx7
89 Vert

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