It will idle for 2 -3 seconds with jumper. Unless I press gas pedal then its like ahhhh F it!

 

fuel filter? Maybe?

 

fuel filter and fuel pump regulator can be culprits. all of which if my theory is right are still in the loop.

this diagram shows electrically what is still in the loop when that connector is jumpered. Confirms the AFM is out. What the ecu does to the injectors I have no clue.

 

Well supposedly the truck sat for a few years before I bought it. I just realized what i'm up against with the filter if thats it. I Have an 86 fully broken down right now but never noticed the location of the FF until now. Is there a way to test for the filter being the issue w/o replacing it?

 

or just bad gas or the fuel level is low, you did say your fuel gauge didn't work right? maybe your either out of fuel or there is bad gas in the tank.

 

After some more reading, i decided to check the COR and sure enough, it works. Clicks back and forth like a relay should so i don't think it is the problem.

 

I don't know for sure if it works or not. I just bought the truck yesterday and drove it home on the rag idea. Could be bad fuel. I suppose I could drain it and put new fuel in it but that doesn't seem to solve the problem of not turning over unless i'm jumped on b+ and FP.

 

whats the easiest way to drain the old fuel out without dropping the tank? Or is there one?

 

I want to say there should be a drain plug on them. Not sure if you have to remove the tank skid or not, I have never done it.

 

Yep, drop skid plate and there should be a drain plug near the rear of the tank. If the tank only has a couple of gallons of gas, I just drop it like that, not that heavy. The first time I dropped mine, I drained it and had blocks and jack stands under it to support the weight. Once I had it down and supported, I found I could lift it with one hand, so felt kind of dumb with all those supports in the way. Next time, I just rolled under it with a creeper and then pulled the 3 bolts on each end and dropped it onto my chest and rolled out with it.

 

ok so I just pulled off the fuel lines by the tank and seems as though the fuel "looks" good. Not gummy or anything. Here is an image of where I disconnected the lines. They are located just before the tank under the body if you were starting from the front of the truck. If I disconnect the left one, (pass side of the two and shown at the top of photo) the fuel spills out at an alarming rate without the pump on. The one on the right (d side) has no activity with pump on or off. (assuming the pump is working as I have heard there is like a fan blade on the pump that may run to stir the fuel but does not have to do with pump action. IMO if the one line will dump fuel, being at the top of the tank, there is fuel pressure? Yes, no? here is a picture.

 

I replaced the COR with the one from my 86 which works, and still same issue. I get an idle for a second with or without a jumper and still it dies. I jumped e1 and t on the diagnostic panel and get a constant flash of the CEL. Thinkin i'm just going to replace the fuel filter and go from there.

Also can anyone tell me if this system is a returnless system and if it is vapor or fuel return.

 

Vapor returns via charcoal canister, fuel returns via fuel pressure regulator bypass line. Does the fuel pump run w/ jumper in and ignition on? You should be able to hear the pump running and hear the FPR hissing (sounds like a small air leak). If not, something may be wrong with the wiring to the COR Fc terminal. If it only runs a little after cranking, that says the STA terminal wiring is fine (that is what turns on with the starter).

 

yes the pump runs with the jumper and key on vs not running without the jumper. Either way, When I turn the key, the motor fires up long enough to stabilize and right then it chokes out. Could the regulator or clogged return line be causing it to choke out?

 

Plugged return line would cause a fuel pressure rise (similar effect to the FSM FPR test where you crimp the return line and listen/look for a rise in pressure). Guess you would need to plumb in a pressure gauge to see if the fuel pressure is falling after it starts running. Might be the pump can't handle the volume of fuel needed:
- http://www.4crawler.com/4x4/CheapTri...rPressureGauge

 

Im changing the fuel filter right now hoping that will help. I figure that worst case, i'm in the mood, at it already, might as well get it done and out of the way.

 

F toyota for putting the fuel filter up under the intake manifold! I have everything undone but can't get the top bolt out for the mounting bracket to get it out. Dammiiiiit! Had to walk away for a sec. Thanks again so far your help 4crawler and XXX.

 

ok got fuel filter out. FINALLY! For fun I jumped pump, turned key and I have good flow all the way to the filter. I assumed this anyway due to pressure when I broke the line loose at the pump side of the filter. I shake the filter into the trash can and what loks like rusty fuel comes out. I'm hoping this is the ultimate culprit in this case. We'll see when the new one goes in what happens.

 

Fuel pump changed. Still seems to have same issue. Will idle for a half of a second longer but still dies. WTF? New COR, new fuel filter. Pump works. Still dies.

 

fuel pump or fuel filter changed?