Fuel Pump - Electric (EFI)

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Date: Tue, 21 Jan 1997 09:33:11 -0600
From: Jack Alford 
Subject: Toy4x4 Digest V1 #45
To: toy4x4@tlca.org

>Don't know if its true, but I heard the Tappet Bros on the Radio tell
>someone that fuel is used as a lubricant and cooling agent for the fuel
>pump, and if you let the tank go empty too often, you'll burn the pump
>out. Since I'm not allowed to work in my wifes 'Runner and all my other
>Toys have carbs, I can tell you for sure if this is the case. They
>seemed to indicate that the pump was actually in the tank. Anyway thats
>what they said...

The part about burning up a fuel pump if run dry is mostly true as most
electric fuel pumps are cooled by the gas. I'd think you'd have to run it 
dry ALOT before you'd burn it up though, I'd think most people would cut
the car off when the engine quit, but hey I've seen people driving down
the interstate on the rim when the tire went flat so anything's possible.

Most, but not all, EFI fuel pumps are in the tank, some are mounted on the
frame rail with a design that prevents gasoline from flowing backwards into
the tank and causing the pump to loose it's prime, a Ford Thunderbird is a
prime example of this, which is why it is a good candidate fuel pump for
GM TBI motor swaps and much cheaper than the hi-po parts catalogs.

 -----------------------------------------------------------------
 Jack Alford              Off-Road.com - The best dirt on the net!
 jalford@off-road.com              http://www.off-road.com/
 Decatur, AL

             '86 Xcab Toyota Pickup -  33x12.50 BFG MT
         Solid Front Axle - Marlin Crawler - ARB's - 4.88's
         SFWDA  -  TLCA #3415  -  Rocket City Rock Crawlers


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Date: Thu, 30 Jan 1997 23:54:34 -0500 (EST)
From: BCSTOY@aol.com
Subject: Running an EFI dry
To: Toy4x4@tlca.org

 I going to reply and be more specific.

If anybody has pulled a fuel pump, it should look like a small cylinder with
a filter screen at the bottom it has a price tag of about $350, does anybody
wants to spend that kind of money for a new pump.

Older trucks such as mine (85/87) that see a lot of of road mudding are more
likely to
have fuel pump problems. My guess is that because most drivers like to go low
toyota has put the pump at the bottom of the tank, that way the pump will use
the gas to lubricate itself and cool itself off from running constantly and
maintaining
a constant pressure.

Overtime that fine plastic screen tends to tear and cannot filter the dirt
created
by the gas ( plus the fact that moisture and other contaminants in the gas
contribute to corrosion in the tank). So sooner or later the pump ends up
sucking
up the dirt and the most suprising thing  is that this dirt manages to go all
the 
way to the injectors. Get suspicious if your spark plusgs have the appearance
as
if they are burning some dirt. It happened to me on my 85 and the symptoms
when you do not know are terrible, you may expereince loss of power any time
, hard starting, the problem can come and go, the truck becomes very
unreliable.

So moral of the story don't try to test the pump's ability to keep your truck
running.
And if your truck is old and see a lot of off-road or use some unkown gas
brand,
may want to check your tank, or better yet replace the screen filter at the
dealer is about $20.

By the way no need to prime the pump, I replaced two on my 85 and my 86 and
the gas float and tanks. I still keep the pump from my 85 it is all rusted
and tries
to run but it recreates the same problem.

You also do not need to run the engine until it runs out of gas, the fuel
pressure is
not so bad, just disconnect your battery for safety when working in the fuel
system.

If you want to run injector cleaner try a product sold by carquest made by 3M
it hooks into the fuel line for about 10 minutes I prefer that one instead of
pouring
stuff in the tank, but you need a special hose too.

I hope this thing is not too long otherwise you guys may not read it.

F. Ornelas

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Date: Sun, 27 Apr 1997 22:08:29 -0400 (EDT)
From: BCSTOY@aol.com
Subject: 22re fuel pump questions
To: Toy4x4@tlca.org

In a message dated 97-04-27 18:08:46 EDT, you write:

<< 1986 22RE electric fuel pump- when you turn on the key should you hear the
 pump begin working or does it only come on when the engine is turning over?
  >>

No, the only way you can hear it runing is if you turn the key on and with a
piece
of wire join both terminals of a brown rectagle connector located by the air
filter, then go to the tank you will hear it runing.

I think I mentioned to you about the possibility of having rust somewhere in
your
fuel system you need to check for that and then the diagnosis can be moved to

the next step.

You need to try an injector cleaner made by 3m and sold by car quest it hooks

directly into the fuel line if that makes the truck start easily then you
know that
you problem is in the tank, if the problem remains with the engine runing out
the
can then you know that your problem could be in the injectors.

F. Ornelas
87 4x4 on the wrks
86 4x4
85 4x4
83 4x4
82 4x4
85 4runner
86 2wd on the works

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Date: Sun, 27 Apr 1997 23:00:08 -0400 (EDT)
From: DRM033@aol.com
Subject: 22re fuel pump questions
To: Toy4x4@tlca.org

In a message dated 97-04-27 22:42:32 EDT, you write:

> F. Ornelas
>  87 4x4 on the wrks
>  86 4x4
>  85 4x4
>  83 4x4
>  82 4x4
>  85 4runner
>  86 2wd on the works
>  
And I thought I had a Toy problem...  :)


David
DRM033@aol.com

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Date: Mon, 28 Apr 1997 10:33:58 -0600
From: Tony Bartlett 
Subject: 22re fuel pump questions
To: toy4x4@tlca.org

If you want to check for a leaky injector hook up a fuel pressure gauge
(I think the easiest spot is the banjo fitting for the cold start
injector).  turn on the fuel pump (I think you can jumper one of the
connectors on the left fender, my manual is not in front of me).  Then
pinch off the return line (from the pressure regulator, on the flex
hose) and turn off the fuel pump.  If your fuel pressure drops then you
either have a bad injector or a bad one way valve in you pump.  Then
turn on the fuel pump again and pinch off the return and supply lines.
turn off the fuel pump.  If pressure drops, you should have a leaky
injector.  If the pressure holds then you should have a bad check valve
in the pump.
Finding out what injector is bad I would need some help(Jim).  I do not
know if there is an easy way besides removing the fuel rail.
You might have a shop (or yourself if you have the equipment) do an
injector cleaning that might free up any particles holding an injector
open.

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Date: Sun, 27 Apr 1997 22:49:40 -0700
From: James Brink 
Subject: 22re fuel pump questions
To: Toy4x4@tlca.org

The fuel pump is activated only when the air flow meter senses air flow,
therefore you will not hear the pump energize when the key is turned.

More likely than a leaky injector, I would suspect a bad fuel pressure
regulator. This is easy to check. With the engine off, pull the vacuum
hose off of the regulator (located under the upper intake chamber near
the rear of cyl. head). If there is fuel present, the diaphram is bad
possibly causing pressure leakdown. Another case could be a bad check
valve in the pump itself requiring outright pump replacement.

To preceisely check for a leaky injector requires a lab scope but a
simple check can be done by disconnecting each injector and checking for
a considerable drop in RPM (a good test-type tachometer helps). If the
RPM change is low, the injector(s) may be allowing fuel to leak past 
the needle valve or plunger. These are moving parts and can, no, make
that will, wear out over time.

If the cold-start injector is either stuck closed or open, or the
injector time switch is bad, starting the truck cold or hot can be
difficult. These components fail often on high mileage vehicles. They
can also cause emssions and drivabilty problems.

Hope I could help.

- --Jim

- -- 
Jim Brink				1986 Standard Bed 4X4/22R
Toyota/ASE Certified Technician		135,000 Miles
brinkjm@earthlink.net			32" BFG All-Terrain T/As
					Stock 4.10 gears
					Rear Lock-Right (TRD)

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