First we pulled the code and datalogged it a bit to see what was happening.. The codes were lean left and right banks. We watched the short and long fuel trims and the short stayed respectable while the long was maxed at 25 %. Finally the computer would give up and throw a code. Unfortunately I'm not completely sure what was going on but after talking to the guy he said something had to be mismatched according to past experience. I didn't think quick enough or I would have pulled the chip and seen how it ran since the meter is supposed to be cald for 55's.(remember that)

Anyway after I got home I pulled the chip and gave her a drive. It seemed better,but the idle was to low. I then decided to take the program I had and put the MAF function to the factory settings and see how she drove and it ran pretty good. Then the kicker

I decided to take my pro m flow chart inside and check it out and thats when I saw it was calibrated for 50's or at least thats what the paper and box say

I'll have to give JDM a call tomorrow to figure out what it actually is, but maybe thats all there is to it. What do you guys think? I would've thought it would have been rich, but ...

Thanks Mike

 

When you set it for 55, it gave you less duty cycle expecting the fuel to flow more freely, but you really had 50's so you ran lean. I know we are talking MAS and not injectors, but the same thing applys.

NoSurprise

 

I'm not sure if you misunderstand me or I misunderstood you, but to make things clear I have 55 lb injectors and the meter says it's cald' for 50 lb injectors. The fuel tables have been untouched, only the MAF transfer function on my program. At this time I have it set to the standard transfer function, but I'm not sure if this is the cause?

 

Do you have the SCT software? If so you need to get access to there private support forum, and someone there will be able to help you.

But, I am pretty sure you will need the ProM to be setup for your injectors, and then you will need to set the values in the software from the values from the flow sheet that ProM sends with the MAF.

 

Yes I do have the software, and thats how I can see what has and has not been changed. I think the program was probably correct, but the meter is not. I've changed the Transfer function to stock for now and it is driving better. It tells you how to reset the transfer function per a incorrect meter, but I'm going to try and get the correct meter first. Luckily I do have a file for my factory meter and the 55's if necessary.
Thanks Mike

 

Good luck on getting a correct meter calibration, I have heard of fresh calibrations being out as much as 45/50% depending on the application.

 

As long as the tuner has the mass air flow sheet and the chip is programmed for the mass air curve of that meter and also programmed for the 55lb injectors everything should work. The tuner should be able to lean or richen the mass air curve.

 

According to Jim the 50 cald' meter is correct as they had it done for them that way. He states the 55's act like 50's while driving and under light thottle conditions. He suggested it was a vacuum leak possibly with the plate that attaches on top of the KB at the back. He said that was a common problem and I will look into that of course.

Now here is what I changed on my program and my driving results so far. I have the MAF transfer function set to the factory 90 mm specs and so far no light, BUT I have not gotten a chance to hook it back up and datalog again. This may only be a band aid, of course I'm only breaking it in right now anyways. There is one thing that did puzzle me though. According to the SCT software if a mass air meter is mismatched you take the injectors its cald' for and divide it by the injectors the computer was cald' for. This will give you a multiplier which you will use to convert the table. This is supposed to get you real close. Problem is it does not match the values that were entered. The values entered are less than the factory settings while the values it says use(according to the formula) are greater. The values entered may be correct, but I find it strange that there is no code with the factory transfer function?? I need to datalog it again to find out though.

Thanks Mike

 

Just so you know, in case you didn't believe him, this is a problem that KB has admitted to me on the phone when I was installing my blower. I made a phone call to them with a question and the gentleman(who was very nice) advised me to pull off the plate and reseal it to be safe. He even sent me out 2 t-shirts for my troubles. Just thought I would let you know. Granted this was back in last June or so. Maybe they have taken care of it since then. I do not know. Best of luck with getting your truck running right! -Mat-

 

Actually I feel he is probably correct or at least I hope so. My KB is one of the first ones so that could easily be the problem. I just found it wierd how the meter was cald' and loaded on the chip compared to what they(SCT) say do. I'll be checking the plate this weekend so I'll know then for sure. I hope thats it

Thanks Mike