BLM Learn is working

[jim_in_dorris]

I finally have my truck back on the road. Drove to town today, and on the way home decided to log the trip. I started out with a BLM of 153 cruising down the hiway, but it soon went to 126 at the same speed and rpm. I guess that 12 psi will work ok. It still needs a little bit of tuning, but for a stock BIN I shouldn't complain. Here is the log. Comments please.

[EagleMark]

Sorry I missed your post Jim...

I thought you put 5.7L injectors in that 5.0L? Sure is adding fuel?

The way it is, whatever injectors it is learning but BLM is awful high in 15x, idle and lower is 114. All stock I would expect closer. If it's adjustable add a pound to 13 PSI. Another thing to look at when idle is low BLM and drive and cruise is high BLM is fuel filter. Could this be getting plugged with all the fuel system work you have done?

Looked again and batt voltage may be what's keeping fuel pump a little low. At cruise you have about 13.4? Should be closer to 14.1... then at the little idle at end of log it was 12.4, when you turned it off it went to 11.8... so do you have a weak battery or questionable alternator? Lower voltage = less fuel from electric fuel pump.

Also the little idle at end of log showed IAC count of 35ish... I'd turn the throttle blade screw in 1/4 turn and get that lower. Lower IAC always helps idle quality.

It's doing it's job! But BLM shows a high low difference in some cells of up to 14! That's a big spread. It's in the ballpark and should be running OK?

[jim_in_dorris]

Yes those are 5.7L injectors, I don't currently have the adjustable regulator in the throttle body, it was one of the variables I eliminated while I was trying to figure out what was wrong. The battery could be a problem, it's an old battery as my battery died in the middle of all this and I pulled the battery out of my son's ford pu which isn't being driven. I will check the output of the alternator as soon as I get a chance. The truck is running quite well, and the log showed improvement in the BLMs at cruise towards the end of the run. I am driving it to work this week just to see how things go. The idle quality seems okay, still does that funny shudder thing, but no worse than when I started. I will put the adjustable regulator on and try 13 psi when I can take it into my son's work, or I can borrow the snap-on tool overnight. I really think that I want to spend the money and put an external regulator on it when I can, it is a real pain to check the fuel pressure the way I do it now. Thanks for responding.

[EagleMark]

Something is wrong then? Those BLM should be all pulling fuel = under 128 with 5.7L injectors!

I always like 13 PSI over 12, but there's no reason to be adding pressure right now. You should have way to much fuel.

[jim_in_dorris]

I agree with that, I have always thought that it should be way richer than it is showing. I just don't know what to look at next. The fuel pump is new, the fuel filter is new, the injectors were cleaned by witchhunter, and I know they flow lots of fuel (when it had the return line problem, it looked like a fire-hose at the injectors). Any thing I should be looking at in particular? It has alway run really lean on data logs. This particular bin has been superceeded, maybe there was something in it? Do you think that there is a mechanical problem I need to look for?

[EagleMark]

This particular bin has been superceeded, maybe there was something in it?

Maybe? But normally superceded bins were emmissions or driveability... what is it again? Let me, or you can too, compare it to another 5.0L Manual? I'd compare the entire bin but especially the fueling tables.

Do you think that there is a mechanical problem I need to look for?

Just the voltage issue is all I can see. How about that dam complcated dual tank switch? Is it still in there? Wonder if it could be slowing down fuel flow?