gpwhite7

I have a 1991 Toyota 4 cylinder Pickup. I let it sit for a couple months and went to start it and it turned over great but never fired. Today I changed the spark plugs and wire set, distributor cap and rotor, still didn't start.

Then I suspected that it was a fuel problem. Troubleshooting this took a long time and I found a few clues which hopefully someone here can help me determine the problem.

I started at the top of the gas tank and followed (2) metal tubes coming from the top of the gas tank and went forward until there was a place to disconnect them. With the lines unhooked I got my wife to turn the engine over. There was no gas coming through the lines when she cranked it. The tank is half full. What does this mean???

Is the fuel pump inside the gas tank?

If you think it could be the fuel pump, how does one troubleshoot the pump?

Isn't it true that when you turn the keyswitch to on but not crank the engine, you should hear a whine noise which is the fuel pump? I am not sure. But I don't hear anything like that.

To further complicate my problem, I bought a fuel filter at Wal Mart which was the wrong one, I bought the one their electronic pad told me was for my vehicle and then I looked all over the truck for a fuel filter that looked like the one I bought (Fram G4191 for $5.00) which is plastic and couldn't find it. Then I called Pep Boys and they told me that it should be a "metal" filter, cost $21.99 and had a different part number.

I would greatly appreciate any help received because I really need this vehicle now.

Thank You!!!

4Crawler

iTrader: (3)

Fuel pump troubleshooting tips.

gpwhite7

Thanks 4Crawler!!! This is great!

Does it sound like the fuel pump to you?
When I took the gas lines loose and cranked it shouldn't gas have been pumped?

Thanks

kevin444

Use this to find the correct part number and hop on by to your stealer.

http://www.longotoyota.com/en_US/ go to parts and service to part catalog to find the part number to the filter.


Id also dump maybe gas treatment just to cure up the gas in there its worth a shot.

4Crawler

iTrader: (3)

Normally yes pump should run while cranking the starter but not normally with the key on/engine off), but if the CO relay is not getting turned on by the ignition switch, then the fuel pump will not run. Put in the test jumper and see if that works. If so either fix the problem or leave the jumper in place (jumper works fine for me)

gpwhite7

I will try this jumper ASAP
Thank You Very Much!

gpwhite7

4 Crawler,

I put in the test jumper on terminals B+ & Fp. The truck did not start but I noticed a few things.

1) With the jumper in place and the ignition switch turned on, but not to the start position I measured the voltage on the jumper with reference to the negative post on the battery.
Results: 10.58 Volts

2) With the jumper out and the ignition switch turned on I measured the voltage on the B+ Terminal with respect to the negative post on the battery.
Results: 12.5 Volts (The same as the battery of course)

Is this normal?

Should the fuel pump pull down the voltage by 2 VDC when the jumper is in?

I am wondering if that is enough voltage to energize the fuel pump.

Do you think the fuel pump is bad?

Please tell me where do I go from here...

Thanks ALOT!!!

4Crawler

iTrader: (3)

Look at the schematic on my page, the jumper has almost nothing to do with the fuel pump itself. All it does is turn on the relay and guess what the jumper does?



It provides a ground connection for the relay coil. Its the relay contacts that send power to the fuel pump. So do you hear the pump running with the ignition on/engine off? Poke your head under the truck on the passenger side, should hear a faint whine from the motor. Or, you should be able to hear the hissing of the fuel pressure regulator, sounds like a slow air leak. If neither audible signs are present, volt meter at the fuel pump connector itself.

Pretacopower

I had the same problem with my 85 when I first picked it up after it sat for over a year. It would turn over, but didn't fire....although it did run on starting fluid for a good 5 seconds.
Turned out to be my injectors, I didn't have any "injector pulse". My mechanic worked on it for me so you might wanna look into that.
Good luck!

Scottz

The voltage drop to the pump sounds to me like it's drawing alot of current but not running, frozen pump.

4Crawler

iTrader: (3)

That would be true if you were measuring the current to the pump, but that is not what is being measured.

gpwhite7

4Crawler,

I will check the voltage at the pump itsself tonight.

I looked at the schematic and see that when you jumper B+ to Fp that this completely bypassing the Main Relay and Circuit Opening Relay and puts voltage on the wire going directly to the Fuel Pump.

When I did this last night with the Switch ON, it sparked when I put the wire on Fp and the voltage dropped down to 10.5 VDC. This seem to indicate that the Fuel Pump is drawing current but not running.

If I take loose the fuel lines (unhook the rubber hoses from the metal hoses) near the gas tank and the fuel pump is getting voltage, should it pump gas onto the ground there?

Why is there (2) gas lines coming from the tank going to the engine? Is one of them a vent line?

I'll let you know if the voltage is at the pump later.

Thanks ALOT for all your help!!!

4Crawler

iTrader: (3)

Yours must be wired different than mine. On mine, the test jumper just turns on the CO relay when the ignition is on. If youare getting power to the pump and it is not running then that is your problem. Check the wiring at the pump itself, may be damage to the wires. If not, replace the pump. Feed line to the fuel pressure regulator input and return line from the FPR return side.

gpwhite7

I doubt if mine is wired different than yours. I was just looking at your print and it looked like "Fp" was downstream of both relays and going staight to the Fuel Pump. But I am just a newbie to car maintenance and am probably wrong. I will post late tonight if there is Voltage at the Fuel Pump.

Thanks again!!!

4Crawler

iTrader: (3)

Mine is an '85 and that is what the schematic is from. Not sure if the wire terminal names apply to the later style diagnostic connectors (the '85 does not have those). On mine, my jumper wire goes into the "Fuel Pump Check Connector", no terminals named or labelled. All that does is bypass the AFM Fc-E1 contact than normally holds the CO relay on. What apparently is a weak point on the CO relays is the secondary winding that turns on via the STA-E1 terminals via the ECU-STA output.

Nathan Buchanan

I've got the fsm for my pickup on my computer. Here's a link to the schematic off a '93:http://www.personal.utulsa.edu/~nath...28fuelpump.pdf . It looks a bit different from Roger's. That, however is all I can tell you
-Nathan

4Crawler

iTrader: (3)

Does look like the Fp does bypass the relay. Different set of connections than on my '85. You could always jumper that with a DC ammeter and measure the current flow to the pump.

gpwhite7

Thanks Nathan for the PDF!
Is this procedure for a 4 cylinder (22-RE) Engine? I am just thinking that I might be needing a procedure for my removing/installing a new fuel pump soon.

gpwhite7

I will try using a DC Ammeter in series with B+ & Fp. Does it normally draw over 10 Amps (The fuse rating on my Fluke)?

Thanks for the good ideas

gpwhite7

I unplugged the connector at the fuel pump and took some readings.

With NO jumper on terminals I had 10.5 VDC on the connector pins going to the fuel pump when my wife CRANKED the engine.

With the jumper in place on terminals B+ & Fp and the key switch turned to the ON position/ not START, I had 12.5 VDC on the connector pins going to the fuel pump.

This sounds bad! It ain't pumpin! So doesn't it sound like the "only" thing it could be now is a BAD FUEL PUMP?

If someone has time, could you just make sure this pump on EBAY looks like it will work for my truck (1991 Toyota 4 cylinder)? And is this the only thing I would need if it is bad? I've never done this job before. THANKS!

http://cgi.ebay.com/ebaymotors/ws/eB...925920471&rd=1