79 toyota p/u,20R fuel issues.

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  #1  
Old 08-16-12, 12:04 AM
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79 toyota p/u,20R fuel issues.

I hope someone might be in tune with this yr. My chilton's does not give location or voltages , or resistance for the resistor on the tank. I know grounds are all going to chassis. Is there a fuel pressure regulator? [ 2bbl webber ].

I have 12+ vdc @ the fuse and next to nothing @ ths pump. Bad connection somewhere, or do I pursue a grounding problem? I am replacing the sending unit and pump since they are 33yrs old anyway. the pump ran when I put 12v to it .Also the book shows a fuel cylenoid only with a yel/ blk wire to it. this wire on the truck only goes as far as the fuse block.

I don't get it. can you help?
 
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  #2  
Old 08-16-12, 05:55 AM
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Been so long I couldn't have told you it was an electric pump. We had an '81 long time ago (think we sold it early 90's).

From your description, I would be hunting for a relay as I don't think the power will be going direct from fuse to pump. What you call a solenoid could be in the ballpark, but a relay would have at least 4 wires.

Will try to do some research and their are dozens of Toyota forums around that might be able to help.

Late note: Just dug out my Haynes and it covers your year, will check wiring schematic, etc.
 
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Old 08-16-12, 06:09 AM
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Okay, right off the bat I found a "Fuel cut solenoid" on the schematic; 2 wires and is powered by the 15A "engine" fuse, so with the key on there should be power to that solenoid and it should be open.

There is a fuel pressure regulator: Location, "Attached to the intake manifold in the fuel supply line". [Pretty standard location].

Main relay: Left side kick panel.

Sending you a pm with additional info.
 
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Old 08-16-12, 06:18 AM
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Also the resistor value is 2-3 ohms.
 
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Old 08-17-12, 02:18 PM
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GREAT ! I now, thanks to you, have a clearer picture of what to do to get this truck back on the road. I'll take a look at it today and see what I can see.
Meanwhile, thank you for taking time out of your day to help out! I will get back to you on this . thanks again. Peter
 
  #6  
Old 08-17-12, 08:08 PM
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I didn't see a fuel pressure regulator anywhere,

all it has is a cheap plastic inline filter on the firewall. a steel vent line from the tank forward that just ends on the firewall, I assume it was to do with a charcole filter. I will research this further online. Meanwhile, I'll see if I can locate the solenoid [cut-off] and check it.
 
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Old 08-18-12, 06:44 AM
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Just in case I missed it somewhere in the discussion, this is fuel-injected, right, and not carbureted?
 
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Old 08-18-12, 05:10 PM
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no, it's a 2bbl weber, no smog stuff,5 speed, 2wd
 
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Old 08-19-12, 03:32 PM
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Oh. Didn't read all the configurations. I don't think that has a pressure regulator on it, maybe just a return hose to the tank.
 
  #10  
Old 08-24-12, 10:52 PM
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still haven't found what the book calls a "fuel cutoff solenoid " behind the driver's side kick panel was a relay that said "charge light relay"

on the D'side wheel well is a box with several wires, no markings, and colors are faded and painted.

A friend of mine said he remembered someone messin under the hood with fuel cutoff wires. . .
 
  #11  
Old 08-29-12, 08:12 AM
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Can anyone tell me where the fuel cutoff solenoid is located on a 1979 Toy p/u ?
 
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Old 08-29-12, 11:25 AM
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I'll give another glance at the Haynes manual later and see if it gives any addition clues, pics, whatever.
 
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Old 08-30-12, 04:56 AM
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Thanks a bunch, Ive been doing bodywork prepping for new paint and waiting 'till the1st to buy a pump and s-unit and oil pan gasket. What a pain to remove the pan! dismantle suspension cross member, torsion bar, steering idler and more. poor engineering. I really think the rest of the truck was designed well. Everything else is easy to service. If I just knew what I'm looking for,life would be good.

Chilton's is so busy trying to cover so many yrs and models that they skimp on the details. The wiring diagram is a joke. you can't read it , even with a mag/glass.I should have gone Haynes.

Do you think it possible to e-mail me an attachment re: '79 pick up [20R] wiring diagram? I suspect your a busy guy, and I do appreciate your time. Some color codes would help. I wonder where I can get a picture of the solenoid or relay or whatever it is that is not giving the pump any juice.

Thanks again
 

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  #14  
Old 08-30-12, 08:27 AM
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Removed your email address, not allowed in the thread. I'll try to scan diagrams and send today.

You have an odd configuration on that truck that leads me to believe it's had some mod work done. A Weber carb would be aftermarket, but if it simply replaced the stock unit, should not be a factor provided it's functioning properly. Something I noticed in the Haynes after you enlightened me that it was carbureted vice EFI - in the fuel pump section it shows (a) Mechanical pump, and (b) Electric pump (fuel injected models) which seems to indicate a carbureted engine would have only a mechanical pump and not an in-tank electric?
 
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Old 08-30-12, 10:06 AM
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Schematic on the way. Hope I got right email address; after editing out in your last post I misplaced the slip of paper. I had to look it up and hopefully it's the same one you registered under. Shoot me a PM to confirm it.
 
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Old 09-01-12, 04:31 PM
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Thanks for the research! I found out yesterday at an auto parts store, the fuel cutoff solenoid is mounted on the carb, hence you are correct about mods. "79 was the year they switched to an in-tank pump because of problems with the mechanical pump. I did see last week, somewhere on line
a newly designed mech. pump that claims to be rid of the problems.

Thhe exact replacement fuel pump is $115.00 and this new mech. pump is about 1/2 that.I think I'll pull the plate and seeif there is a cam lobe inside. On the tank side, I would just have to pull the e.pump and replace it with 6" of tube to the screen.There is a steel return line availible , I would just have to figure out if I need it, or not, and the only other thing I see is perhaps a regulator.I'll try to look into the specs on the meck pump, and get back to ya.PS: no E-mail, I DO appreciate your efforts talk with you later Thanks again
 
  #17  
Old 09-02-12, 01:56 AM
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Cam has what it needs to go mechaniclal, as long as I can find one that hangs down, as to not interfere w/ top rad. hose I'm leaning more towards going this way.

I found out the relay should be under dash, over steering column ,I'll be back tomorrow,I'm going to check it right now!. Enjoy your weekend...
 
  #18  
Old 09-03-12, 03:04 PM
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WARNING!: Make sure the mounting for the mechanical fuel pump doesn't require a spacer!!! If it does and you mount the pump without it, it will break the pump the first time you turn it over.

Voice of experience: Had a '74 Celica with an 18R-C that I put a short block in circa 1982. Didn't notice the spacer stuck to the old block when I did the parts swap.
 
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