jw1044

I am trying to get a 1986 SR5 running after it has been sitting up for almost three years. It has two major problems. First the wiring has been chewed up by mice. I have hopefully repaired this damage.

The second problem is that the fuel tank was completely rusted and the fuel pump was dead. I have a new fuel tank and fuel pump installed but I am having problems getting the pump to work. When the key is turned on I am not getting any voltage reading on a volt meter. When the key is turned to start, the meter reads 12 volts with the pump out of the tank and grounded to the battery. The bed of the truck is very rusty on the bottom and does not seem to be making a good ground.

Can I run 12 volts to the pump and a new ground to the battery, and is this the best way to solve this problem? I am open to any suggestions and ideas.

The truck has 127,000 miles, a 22r-E engine, and was running great before it was parked. Could the wiring repairs be a possible culprit in this situation?

Thanks

scope103

Yup, sounds like a bad ground. My schematics show a separate wired ground (not grounded through the tank), but I've never actually seen one.

You should get 0v with "Key-on," and 12v with key to Start. (As the motor cranks and pulls air through the VAF, a switch in the VAF also supplies current to the COR and keeps 12v on the fuel pump). So that part sounds good.

First, I'd look for a broken ground wire to the tank. If hard to repair, just running a new one from the battery would be fine. Don't run a new 12v line. You'd need to switch it (you don't want the pump to run all the time), but more importantly, you really need to run it through the COR for the safety aspect (if you get a collision that breaks a fuel line, you want the pump to stop immediately).

myyota

You wont get any voltage to the fuel pump until you turn the key to start. Check the wiring from the pump to the COR relay, and also check the COR relay itself, they can corrode on the inside or just go bad. Also try running a ground wire to the battery and see if that helps.

jw1044

Thanks for the help. I grounded the fuel pump and am know getting fuel to the filter. It will crank and idle but only when I close off the air to the fuel injector housing. I will replace the fuel filter but I haven't figured out how to do that yet. Any advice there would be appreciated.

Also the VAF and COR relay were mentioned. What are they and where are they located?

scope103

Volume Air Flow meter http://www.ncttora.com/fsm/1990-1995...e/volumeai.pdf and Circuit Opening Relay http://www.ncttora.com/fsm/1990-1995...e/circuito.pdf

What do you mean "close off the air to the fuel injector housing"? If you have the intake air connector disconnected from the throttle body, that won't work. The ECM takes the signal from the VAF to determine how much fuel to add; if the air isn't going through the VAF it can't run. More specifically, the switch in the VAF is what keeps the fuel pump running after your release the key from the Start position.

Terrys87

iTrader: (1)

The COR is loated right behind the passenger speaker on the dash. You will need to remove the speaker to see it.

The VAF or the part above the air filter. It will need the pipe hooked up for it to run. I have had mice problems and would suggest literally going over the harness inch by inch looking for further damage.

You could run resistance checks, but I find for mouse problems it doesnt take near as long to check the harness for me personally.

jw1044

I removed the air intake hose from the air filter housing and closed it off with my hand. That was the only way it would run at all, but only idle. After reading other posts I realize what the VAF valve and the COR relay roles are in this process. I have to test them and see if they are working correctly. Thanks to this forum I feel better about getting this truck running, with the first step being replacing the fuel filter when I figure out how to do so.

Thanks

uncleblues

if you don't mind the work, unbolt the clutch slave cylinder and take off the starter-there's not much room to manuver under the intake where the filter hangs on the side of the engine