New to TBI Data logging and such.

[georgeb]

Ok, will do. I will need to get a fitting for the fuel pressure tho. I was thinking of a permanent gauge anyway.

[georgeb]

One more thing. I currently have the timing set at 8 deg advanced over the spec 0 deg. It seems to run better there. I assume it would be best to set it back a 0 correct?

[jim_in_dorris]

yes it would. What happens is that the 8 degrees you have set in timing gets compensated for by the tune, and so you don't gain anything. If it really runs better at 8 degrees, it would be best to actually put it in the tune.2-4 degrees doesn't matter too much, but beyond that it does. I can't remember correctly, but i think it takes out that 8 degrees of timing in the tune. It would be like pulling timing by 8 degrees across the board. the best way to play with timing is in the tune.

[georgeb]

Ok, here is one of a drive out of town and back with some in town driving. I have the timing back at 0 DEG and I measured my fuel pressure at 10-11 PSI.

[jim_in_dorris]

All in all, not too bad. At a steady cruise your BLM is right where you want it. However when you stab the accelerator, you are going lean. The first thing I would look at is your injectors. At a dead idle, are they dripping? does the spray pattern look good? when you hit the accelerator (in park) does the spray pattern look good and does it appear to add more fuel? If your injectors look good, I would consider bumping your fuel pressure. Take your injector pod off, and add a washer to bump it to 12-13 #'s and see if your hard acceleration BLMs are a little richer. I wouldn't worry too much as long as you aren't racing, I ran leaner than that for years without a problem.

[georgeb]

Ok, I will check those things. The injector spray looks ok at idle with no dripping however I think I may try to clean them anyway. I will look for it to add more when I open the throttle. I am also going to try the washer add for more fuel pressure and see if it comes up a bit. When you have the time could you explain how you determined the lean condition? I imagine you saw the blm drop off when the throttle is opened and then recover. I don't fully understand how this all works but in order for me to continue with a TBI system I need to understand it and be able to tune it. I am just a bit spoiled by having the ability to tune my Q-jet. I have learned a great deal already and really appreciate all your help!!!!!

[jim_in_dorris]

anything above 128 in the BLM's (long term fueling) is lean (not really too probamatic until about 138, and not serious until above 145. below 128 is rich. The BLM change on throttle stab is AE (accel enrichment, think pump shot on a carb.). That is an area that frequently needs work to make a tune work like a gearhead wants. The other is DFCO, decell fuel cut off. when you get ready to tune your truck, there is an excel file that Dave W. built that lets you make fuel corrections to the tune.