my blm's r in the 135-146 range driving on the highway!!

[Ron Coleman]

i have this problem for a while. it raises when i accel and stays in that range untill i let off the gas and go at a lower speed and then it goes down to about 122-128 range....it's like if i keep it at a lower speed it stays below the 128..i go wide open and no knock o2's in the 820-830 range at 16 ponds of boost...anyone know what it could be?? im going through gas like crazy!!

this is what i changed so far:

o2 sensor new delco
fuel filter
fuel sock
fuel pump
injectors from 50ilbs to 36ilbs
fuel regulator
pvc valve
put gaskets on the headers

new iac valve with gasket (i was reaching for anything here)

i sprayed all the vacuum lines and nothing because i thought i had a leak.....
the only thing i didn't change is the maf (maf is 5-6 idle) and plugs and wires
the thing is the bl's stay in the 125-128 range at idle

 

[mikestertwo]

What mods, what chip??

 

[2QUIK6]

If you have a scanner, notice what your MAF gpms reading is at different rpms while going down the highway when the BLMs are high....
Then notice the MAF readings at similar rpms when driving around town when the BLMs are in the 125-130 range.
Most likely the same BLM cells are being used in both cases... for reference
Block Learn Multiplier and Integrator
Probably cell 11 and 15... the difference is the MAF gps reading is probably alot higher cruising down the highway than just cruising around town in 3rd gear. (assuming your not going fast enough for it to shift to 4th).

I've observed this with many chips inclusing the stock chip as you mod the car for better air intake flow, as most chip makers only adjust the idle gps part of the MAF tables ...gps of 4-8. What needs to be done to bring those BLMs in line with the others is adjust the MAF tables at the gps reading you see when cruising down the highway...being that you are lean, then the MAF table number (gps) for that frequency reading needs to be increased so that it will command more fuel at those MAF gps readings and bring the BLM# down.
It really doesn't create a problem, but the extra gas could be consumed when you slow down and the BLM# has not been adjusted by the ECM yet and its commending more fuel than you need when going slower and still using the same BLM cell#.
I wouldn't think it would make a huge difference in gas mileage though.

This is where mail order tunes are just a guess without a good long scan recording of various driving habits to be used to make the adjustments.

 

[TurboDave]

High highway cruise numbers are a little unusual, in that most chips yield lower highway cruise numbers than the rest of the cells. Cells 7 or 11 are the usual highway cruise cells and most chips run them down in the 1teens or so.

This doesn't mean yours is wrong. The numbers you're seeing are not out of the ordinary and certainly nothing to even be concerned with, since they are well withing the range of adjustability, meaning they are not maxed high or low..

As the author of the article 2quick6 references, I would highly recommend reading it. Hopefully it'll clear some things up.

 

[Jerryl]

......... As the author of the article 2quick6 references, I would highly recommend reading it. ...........

Dave, did not know you authored the article.
Just wanted to say "Thanks" for sharing your knowledge!

 

[Ron Coleman]

ok ...i read the artice ....good read ty

the chip is a joe lubrant chip for 50 ild inj
i never had this problem since having the chip/inj for 3 years
reading the article im going to get myself a MAF and c
bye the way i didnt mention but iM running a translater. i made some adjustments but no good.
also switched ecm ..i didnt mention this in the first post, sorry
i would like to know if the wires and plugs would cause this condidtion ..they r ac delco wires and 43 ts plugs..there in 2 years already..
thank you guys for the help.. this is my daily driver:smile:

 

[BRAD_PADGETT]

Ron. I had the same problem and in my case it was fuel pressure. It turns out that my TT chip was adding fuel while cruising. My solution- raise fuel pressure slowly and my BLM now stay close to 128 while cruising. My 2 cents. Brad

 

[2QUIK6]

Adding fp will effect all BLMs, it may lower your highweay cruise BLMs, but will also lower your idle BLM.
You may be able to adjust the idle fueling a little with the trans+, seems like there was a setting for that so thatr maight allow you to do something with the fp and then adjust the idle back to around 128.
As Dave mentioned, even at 146, the ECM is still in full control of the fueling, but of course getting all of them around the same makes for a better transition from different rpms and loads without sometimes feeling a "flat" spot when its running too rich or lean for a few seconds.
The Trans+ will have no effect at cruise / light throttle, only adjusts WOT fueling and spark.

 

[BRAD_PADGETT]

2QUICK6- Is correct. I increased fuel pressure very slow and kept my BLM at 128 at idle in park and the cruising BLM within range -less the 138. Good luck. Brad