Hello guys, I am having trouble getting the truck running. Long story short, I had done an oil change, and wanted to clean around the intake and throttle plate and had undid the two screws and broke solder joints. Jumped B+ to FP and drove her out the drive way and the truck sat for about a week while I was looking around for a used AFM for cheap. I had already attempted to repair the damage on the AFM but unfortunately FC and E1 had no continuity. Went to install the used AFM, swapped components over, hooked up all the lines and it'll just crank and crank and so on. Tried jumping B+ to FP but same issue. Unhooking the AFM then shows AFM/COR symptoms, crank, start for one second, then dies. Bypassing to B+ to FP with AFM unplugged still won't get it running.

The Fuel Pump is audible I open the trap door, as well bypassing it. I have went over the circuit for the fuel pump, checking resistance for the fuel pump through Diagnostic Port, EFI fuse is intact, EFI relay is clicking and activates the fuel pump, COR is good, and checking for 12V through the plug from underneath the little access panel under the seat, as well checking resistance to the fuel pump there. Measured resistance on the distributor plugs and everything is in spec and checked cap for any corrosion. Fuel Pressure Regulator seems good and fuel is flowing out through the return line. Checked whatever accessible grounds and they seem good.

Current the situation as it goes, with the used AFM hooked up, it'll only crank but no start. AFM unhooked, it will start for one second, then stall, likewise with B+ to FP. Truck ran fine before it was parked for about a week. Hoping you folks here could chime in and see how I would go from here before I start going in deeper.

 

Replace the fuel return line with a line to a suitable container. With the FP jumper in, I get about 1/2 liter/min (there is no spec.) Now, start it (be really careful about splashing fuel). Does the fuel keep running? Does the fuel stop running before/after the engine dies? Does the VAF make a difference?

 

I've jumped the pump through B+ and FP with VAF disconnected only key on and had a clear tube hooked up to the return line on the FPR. Watched the fuel slowly coming out for about a minute but definitely not 1/2 liter in my little bottle. Battery probably dipped below 12V at this point so it's sitting on the tender. I will try starting with and without VAF later today and post back.

 

This suggests that when the injectors start opening, the pump can't keep up and the rail pressure drops far enough to kill the engine. Once you get enough battery charge to turn the starter, you could check that directly. If the fuel flow out of the FPR stops when the engine starts, it won't run for more than a few seconds.

The most likely culprit is the fuel filter. It's a maintenance item so you should replace it anyway, but it is kinda a big job. https://www.yotatech.com/forums/f116...ctures-218962/

You might have an electrical problem preventing the fuel pump from getting full current. You can check that with an ammeter. https://www.yotatech.com/forums/f116...-quits-312747/

 

Appreciate the input. The body itself has approximately 370,XXX km on it but the motor is maybe 160XXX km. Fuel filter is definitely on the list. When I have some time and a buddy I will test the fuel system and post back results.

 

Got the battery hooked up and checked the current through B+ and FP and it reads 4.18 amps. Turned the key and still didn't make a difference. Just picked up a fuel filter and will probably get a new fuel pump as well. Will pick a good day to drop the fuel tank and get it all done and cleaned up and start working my way upstream.

 

Quick update, installed the new fuel filter but no change. I suspected a vacuum leak at this point and took a look around the vacuum lines near the EGR and some hoses going into a 2 to 1 port crumbled in half. Will replace these hoses and see how it goes.

 

SOLVED. After scratching my head for a while figuring out why the truck wouldn't run with FP and B+, came across another thread from a while back that had a similar issue. Checked continuity on the used AFM I had picked up, and found E2 and VC was open. This meter had already been tampered with and so I opened up the cover and sure enough, the harness had been yanked out and just put back in but not soldered. Soldered E2, VS, and VC and have continuity with each other, but resistance values not in spec. Threw it in the truck anyway to see if it made a difference and she fired up and ran beautifully.