While on drag week during the drive to the second track about 2 hours in, driving at about 55mph the truck leaned out quickly and shut off(happened in about 10 seconds). I tried to restart while coasting, but didnt restart, after pulling over to the side of the road I hooked up my lap top and everything looked normal. I tried to restart it and it immediately fired up, but it is now running very lean(idle afr at high 16's was high13s) and running like crap. I drive down the road to a gas station to investigate more, my first thought is the fuel pump is going out. open the hood and check the gauge on my regulator, pressure is normal, as a test I commanded on the secondary fuel pump but it was still running the same. I added fuel to the entire map to limp through the week(this smoothed it out at some afrs but not at all rpm), also afrs would not stay consistent day to day or really any time the truck was restarted. Since home I've taken apart the fuel filter-clean, checked the socks on the fuel pumps-clean, replaced the wideband's o2 sensor, checked for vacuum leaks, tried a second ecu, all with no change. Anyone have an idea what I should look at next? I'm going to pull the injectors out this weekend and check if the baskets are clogged but after that I'm out of ideas.

 

What ecu?
Is it maf?

 

Megasquirt II, speed density.

 

Have you verified your wideband?
How do the plugs look?
Vacuum leaks?

 

I replaced the sensor as it was a couple years old, but no change in afr's or drivability. Plugs looked black, but adding fuel makes it run/drive better. I checked for vacuum leaks and didn't find any, but I'll probably recheck after checking the injectors.
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How ´s the MAP looking? are kpa corresponding to actual engine pressures? Are you using the internal ECU MAP sensor? if yes, how is it referenced and how does the line look?

 

Map corresponds with engine pressure. Using internal map sensor. Have not checked line, but its referenced to the intake manifold.

 

Is the fuel pressure different than what it was previously?

If the ECU MAP reading and actual engine MAP are accurate and the same as previously and your O2 sensor is not causing this via EGO correction, then attach a datalog and tune. It would be great if yo had a datalog from when it was running correctly.

 

check your timing and see if it has moved

 

This morning I pulled my injectors to see if the baskets had trash in them, they were clean. I swapped my injectors out for some 210's I have, and put a rough tune in. So far afr's seem to be staying consistent, I'm going to drive it again later to see if its still the same. I'm going to ohm check the injectors I took out on monday (my multi meter is at work)

 

Did you ever figure out the problem?

 

Not quite, I suspect the fpr. My fuel pump had sounded a little funky since it shut off. I put the other injectors back in, and was resetting fuel pressure, I backed the regulator adjuster all the way out and then back to normal pressure and the pumps sounded normal again. Afrs are much better, but not like they were before. Racing seasons over so I haven't messed with it too much.