Theirons84

Working on a '93 model 22re as the title states. Symptom when it was last run was that it was sitting idling and when the owner returned, it had quit. Attempts to restart were not successful. They had questioned and worked on some of the ignition system, and had no luck.

When I got to the truck it had no coil. I replaced that and put a new battery in. Truck cranks over fine. I have spark on all plugs and they are also new plugs. Ignition seems okay. I can open the butterfly and spray starting fluid in, and it cranks and runs pretty rough for a few seconds. (I assume because of sitting for so long.

So I have turned my attention to the fuel system. I suspect the pump with it having sat for so long. I don't know how to tell about a few things.

I'm not sure how much fuel is in the tank. When I turn the key, the fuel gauge stays below the empty mark. I don't know if this is normal or if it should jump up to register how much fuel should be in there. -Or, does the truck have to be running for the fuel guage to register?

I'm going to get some gas now to pour in so I'll know that it does in fact have fuel. (I am aware that if the fuel pump is bad the sending unit might be too, and that's why I am not seeing a gauge reading).

Second, I can't find a good spot to disconnect a fuel line to see if I have fuel coming out. Anything up top easy to get to?

Fuel pump fuse is fine. Have not checked the relay but I will. Also, I am aware of the fuel pump shutoff and I think it may be in the passenger floor kickpanel from what I have read. I will check that too.

Any hints would be appreciated.

scope103

The fuel gauge works with key-on. Doesn't need to run.

The easiest way to check for fuel flow is by disconnecting the fuel return line at the fuel pressure regulator. http://web.archive.org/web/201311071...30fuelpres.pdf Then jumper B+ to FP on the diagnostic connector; with key-on the pump is forced to run even if the VAF COR circuit is bad. You should get about 1/2 liter/min out of the return line with the engine not running.

Why do it that way? Everything on the high-pressure side is sealed with crush washers, and they are all one-time-use. So don't open any fuel line without getting the crush washers to replace. But on the low pressure (return) side, no problems.

Theirons84

Thanks for the reply. I have been working on it all day and made some progress.

The truck definitely cranks and runs on starter fluid. Ignition system seems fine. Fuel pump fuse and relay both check out fine. And there is definitely power to the relay terminals.

I went and got five gallons of fresh fuel just to be sure it had gas in it. Since you say that the fuel guage should work with the key on, it did not initially.

I figured the problem must be somewhere between the fuel pump relay wiring or the pump itself. I had someone turn the key on while I put my ear to the tank and I hear no indication of the pump running.

Whacked the tank with a 2x4 and now the needle on the gauge rises when the key is turned on, but I still don't hear the pump.

I have taken the bed off and will probably try a new pump in the next few days.

I will definitely try the return line thing like mentioned before I do a new pump.

Thanks.

RJR

The fuel pump should not run with the key on unless you have B+ jumpered to Fp in the diag connector, as scope already mentioned. It should run with the key in the start position, but might be hard to hear with the starter turning.

Jumper B+ to Fp, turn the key to ON, and listen for the pump before you do anything else. Then do the fuel return line test that scope suggested.

These tests are so easy that you should definitely do them before replacing the fuel pump, which is expensive and difficult. (although less difficult now that you already have the bed off.)

Theirons84

How long will the pump run if the jumper wire is placed in? I'm wondering if I have enough time to try it by mysel - by putting in the jumper wire, turning the key to on, and then going to the tank to listen and feel.

I know most I've heard only run for a few seconds when the key is turned to on.

RJR

It will run continuously under those conditions, until you either pull the jumper or turn off the key.

Theirons84

Ok, just checked that. Jumped it and turned the key on. I feel no vibration or anything and surely can't hear it. I'll check the return hose tomorrow but ai'm betting the pump is bad.

Now the question is, if it is the pump, what is a good one to get. I know OEM pumps are usually better than the parts store pumps. If there is a parts store pump that is decent and you all recommend, please let me know.

I have O Reilly's, Autozone, Advance Auto parts, Napa, and maybe a Carquest near me.

scope103

We're all in a hurry, but you'll save a good piece of change by going with RockAuto. That doesn't tell you which one to get (they had 15 different ones when I just checked), but you'll be the one doing the picking.

In my truck, I can hear the pump while standing at the diagnostic connector. But in the spirit of doing the hard things (pulling a fuel pump) AFTER doing the easy things, I suggest putting your multimeter on B+ to check you get 12v with key-on, and your ohmmeter on FP to see that it is low-resistance (less than 10ohms) to ground. If you get high resistance you could have a broken wire from the fuel pump back to the front of the vehicle. (You could also have an open in the pump itself, but I would do a visual inspection of the wiring in that case before pulling the pump.)

Theirons84

Good advice. I was not sure how to check the things you just listed, but I do now. I will try those tests before ordering a pump. I know about rock auto and have ordered from them before. I am glad you mentioned them as an option.

I am not really in a hurry. I just asked about brands of pumps because I figured someone here may know the brands to avoid and brands that are good. As much of a pain as the job is to put a pump in, I don't mind spending a little money to not have to do the job again vs having to pull off the bed again to replace a cheap pump, even if it does carry a warranty.

Theirons84

Just checked and have 12 volts from B+ to ground. Must have an open condition on Fp to ground, because my meter is not even showing continuity.

What exactly does Fp to ground tell me? Is that checking the wiring from the Fp terminal to the pump?

If so I guess the likely cause is an open in the actual pump, but I will check continuity between the pump connector and the FP terminal. Any idea what color wire on that pump connector correlates with the Fp connector?

scope103

Fp (color Blue) connects directly back to the fuel pump (as does pin 1 of the circuit opening relay). As you indicate, the most likely cause is an open in the fuel pump (bad pump). But if the pump were good and the wire to it disconnected, same result.

Checking from the connector on top of the tank back to FP would be smart. It's in the 2-pin connector; the 3-pin connector (4-pin, but with 3 wires) is for the level sender.

Theirons84

Wiring is good from the diagnostic box to the plug. Also have 12 volts at the plug near the tank with B+ and Fp jumped and the key on. Checking the two terminals on the plug attached to the pump shows an open. New pump ordered from RockAuto and should be here In a a few days.

Terrys87

iTrader: (1)

I seen where you tapped on the side of the tank to get the fuel gauge to work. For a truck that has been sitting 3 years, first thing I would do is get the fuel out of the tank. The gas we get now a days is poor. When you get inside the tank, it could possibly look like it is rusted up really bad. I have worked on numerous tanks. What looks like rust is actually chemical build up or gas breaking down and leaving deposits every where.

I have cleaned many tanks and when cleaned, there is no pitting at all in the tank when done. Your fuel gauge most likely has some crud on the lever and may not let it move freely. I have had some bad ones and with some PB Blaster and a brass tooth brush I have gotten them to work. Get around the pivot point real well.

When cleaning a tank, I suggest not to use the drain plug as the crud built up around the threads will strip it out and you will have a leaking tank. I have used Red-Kote to fix a leaking tank.

Just for future reference, if a truck as sat for a long period of time, I will not crank it right away. I will pull the plugs and start soaking the cylinders in Marvel Mystery Oil to help free up the rings. They can rust to the cylinder walls. The starter is powerful enough to break the rust but usually what happens is it will break the ring and eventually a piece of the broken ring will come out between the piston and wall leaving a gouge in the cylinder and it will need to be bored around 20 thousands to correct the cylinder. If I get a chance in the next few days, I have a motor I use as a reference that has the rust ring and a gouge to show what I am talking about. After your rings have soaked awhile, take a wrench or socket and see if you can turn the motor over.

Here is what the float assembly can look like but just a little scrubbing can get it working great again. In each of my build threads below, usually the first few pages I show different things to look for in the fuel system. One of the first things I start working on when I tie into a new project.

Terrys87

iTrader: (1)

This is from a current project I am eventually going to be working on.

Copied from my 87 SR5 build thread.... https://www.yotatech.com/forums/f199...estore-288712/


This is not uncommon to see what some fuel pumps can look like. It looks like rust. I believe it is a chemical build up. I have cleaned many tanks and when cleaned there is no pitting in the tank. One reason I dont run fuel cleaners thru my tank. If it has a lot of build up in the tank, you just dissolved it and clogged your fuel filter. The fuel filter will not catch all of the gunk and can clogged injectors. I also get my fuel pumps off of ebay for about $35 shipped. A Toyota dealer wants about $300, part store $150, and Denso is about $150. I have never had a ebay pump to fail. Just dont run your tank on empty as that destroys all electric fuel pumps. Gasoline keeps the pumps cool.


Tank is in great shape. All of the gunk in the tank can be cleaned. It will have fish scale on the sides of the tank and the bottom will have up a 1/4 inch of build up. I put some white vinegar in the tank to start breaking it up. I normally clean tanks in the winter. The fumes are what are explosive, not the liquid gas. I got half of a coffee can of this gunk out of the tank.

Theirons84

Hopefully it won't be that bad. I hate that I poured five gallons of fresh fuel in, because that likely mixed with whatever was in there. I guess the plus side is that since the pump was not working, it hasn't tried to pump whatever might be in there through the lines.

Another question I had is where is the fuel filter? I think I might see it on the passenger side of the engine under the intake and fuel rail - or is that something else?

What I will do is let the pump run for a few days of driving it after getting it going, and let the old filter catch most of the stuff. Then I'll change it once all of that is (hopefully) been pushed out. I know the strainer on the pump will block most of it, but maybe I can catch the bad varnish and bad gas.

scope103

Here's a picture of it. http://web.archive.org/web/201501160...28fuelpump.pdf

(This is where you say "hot damn!" I'm glad I don't have a 3VZE.)

Terrys87

iTrader: (1)

The fuel filter is under the intake and it can be a pain to get to but I hear it is easier to get then the 3VZE. I have a certain wrench that I can get to the rear bolt of the filter and depending on which truck I am working on there are a couple of different ways I get the front filter bolt. To unmounts the filter from the bracket, I use a 1/4 drive set to get the mounting bolts.

I would tilt the bed and pull the fuel pump assembly and see what the tank looks like. Sometime getting the bracket to separate from the fuel line can be impossible. If that is the case I just leave it attached. That bracket assembly can be expensive and hard to find. Be careful not to twist the metal line in two.

In worse case scenario, running that bad fuel thru the system can clog injectors https://www.yotatech.com/forums/f199...5/index62.html I probably have 5 or 6 build threads on here and in case the fuel system has been in bad shape when trucks have sat and I try to show it in all the threads. It may be that I live in the Midwest and the humidity is higher here then in other places so may be one reason my fuel systems are in bad shape.

Fuel systems are out of sight and out of mind so is easily over looked. I try to make others aware of a possible problem. I have cleaned out clogged injectors. It is easy to do. Also check fuel lines. Crimps in the injector harness is a poor design and can be a problem in humid areas as well.

Theirons84

Well I wasn't so lucky. My tank looks about like the pictures you posted. I pumped out 6.5 gallons of fuel, (5 of it being the new I just put in). All of it is a deep rust red color. I guess the good fortune is that the pump was not working so it didn't pump that crap through the lines. I scraped chunks off the bottom of the tank. I can see the bare metal so hopefully it is mostly just sludge and stuff from over the years settling on the bottom. Nonetheless it will have to be cleaned out.

So it looks like removing the tank is in order. I can think of about 5 things I don't want any part of in life, and cleaning a gas tank out is one of them. I've done it a few times on motorcycles and once on an old car. Guess I better suck it up and get over it. lol

I'm gonna get some vinegar and let that sit in there a few days. See how that works out.

Terrys87

iTrader: (1)

It will clean up to shiney metal with no pitting or rust damage inside the tank. If there is going to be rust, it is usually on pickups and not 4Runners in my experience. The 4Runner has better protection but the pick ups the rear tire slings mud up on top of the tank and it just sit there and will rust holes on top of the tank. Tap on top of it real well and make sure it is worth cleaning.

Theirons84

A week in and making progress. About 75% bare metal on inside - just like stated. I cant reach the back of the tank on the sending unit end. I'm doing my best. Hopefully get it cleaned up within the next few days.