Title pretty much say it. I swapped from a 165 to a 730 and just noticed no matter what MAP value or RPM, I am in Block Learn cell #4. Anybody got an idea of whats wrong? I have tried enabling and disabling the constant for magnetic speed sensor. My guages and datalogs all show correct MAP values, RPMs and engine speeds. Need a suggestion of where to start looking. Only other thing I have noticed is sometimes it doesnt like to go to closed loop mode. Don't know if that's related.

 

anyone?

 

Cell 4 is a "special cell" used in Idle and PE for SD cars. Are you in Closed Loop? Is it showing you in "Learn"? Something does not appear to be correct that is causing it either to not be in Closed Loop or preventing you from going into Learn Mode.

If you are using an eprom, you may not have "quite" erased it long enough (I've had that). Start by clearing the ECM's memory and redoing the eprom with a stock AUJP1615 BIN just to see if you can get BLM readings other than Cell 4.

 

Not like I claim to know what I am doing, but I do perform a "blank check" of the eprom before I write to it. I will cut an aujp unmodded bin and try that though - sounds like a good idea.

As for closed loop, yes it is in closed loop, although somtimes it wont go in and I have to shut the engine off and start it again to get it to go into closed loop. Learn Mode??? How do I tell? (Using Craig Moates' software) I dont remember that title in my logs, but I will look.

Thanks for your help...I let you know in a couple of days.

 

Ok, tried AUJP stock bin. Ran really rich (30# injectors & 50psi). After 200 seconds, it dropped into closed loop. Itegrator and BLMs dropped like crazy (expected), but no matter what RPM or MAP, still cell 4.

 

Now, just set the Injector to 30 (to get it closer) and if that doesn't work, sent the BLM Minimum and the BLM Maximum constants both the 128 so you are running only on the INT and not updating the BLM.

 

Problem solved. For any reading this thread in the future, the following is from Mike Davis via email and has some good info that I thought I'd share:

"Is the vehicle speed being seen in the ECM? How about coolant
temp? The 'learn' mode of the ECM is enabled when the car is
in closed loop, is warm enough, and is moving (driving). You
will stay in cell 4 if sitting in neutral and reving the motor,
or if the ECM doesn't see any vehicle speed or doesn't see the
car has warmed up (over 120deg is the stock setting I think?)

Vettes that I've worked with in the past have had issues with
the VSS in the trans not being hooked up correctly with the
swap ECM..

(There are rewiring changes for the ECM to correspond to switching
the Mag. pickup BIN flag...)

sounds to me like the ECM is not geting correct VSS??

mike"

Actually, the data logs show MPH and 180's for coolant temps. Car was definitely closed loop with INTs and BLMs adjusting.

I went back to the chip I have been working on because the fuel was generally close and changed my sparkplugs, some of which were fouled due to running too rich.

Magically, it starts going into other cells. I swear the only difference is the sparkplugs.

 

I have noticed that occasionally I will burn an eprom and it may stay in Cell 4 more often than it should along with erroneous BLM/INT values like the BLM "sticking" at 150-160 but the INT going very low (below 110). If you averaged the two, you get close to 128-130.

Clearing the ECM (by cutting power) and reburning the eprom has always fixed it when this has occurred. I haven't noticed this in a long time, but it has happened on the odd occasion.

 

I am noticing the same thing that BLM stay in cell 4. I am trying to tune it to idle in park so does this mean the ECM will not learn unless the vehicle is moving? I have been adjusting FP and Inj. Constant all morning and the car is just shooting to either end of the BLM range (too rich or too lean) once it goes into closed loop. Should I go ease around the block to get this thing learning or put it in gear on jackstands or something?

 

Unless cannistor purge is active, cell 4 is where it'll be. Of course when cannistor purge becomes active you can't tune anyway.

RBob.

 

So it should stay in cell 4 no matter what, idling, cruising around, open loop or closed loop, unless Canister Purge is active?

 

If I remember correctly. I don't work with the $8D code too much. I do remember this problem cropping up (here) all of the time and looked into it. That is what I found. If someone else can check the code it would be a good idea.

RBob.

 

I looked over several older posts and see the same thing about some ecm's being stuck in cell 4 and others saying they have cells that vary. There was not any definate answers one way or the other as to whether it was normal to stay in cell 4 or not.

 

Updated to include the possible fixes for this problem...

Stuck in Cell 4 - No or Bad VSS
Stuck in BLM cell 4 - CCP Minimum Duty Cycle
CCP disable = cell blk 4

Tim

 

I'm having the same problem. After I did the six-speed swap, I'm stuck in cell 4. I have a SGI-5 cal box and my speedo reads fine. Datamaster is also showing speed signal and the car is running about 170 - 180 degrees. So, it appears that the ECM see's all the signals. Any suggestions?

 

ttt

 

Don't know how helpful this is, but:

I have also done a t-56 swap. I'm running AXXD now. Using the t-56 VSS with the road speed constant and dash/speedo divisor set appropriately. Haven't touched any of the CCP code/settings.

my block learn cell changes as normal.

 

bump bump, bump it up....

I am having the same issue with my car. it's getting stuck in BLM 4. i have tried messing with BLM boundaries too, and sometimes it will work but most of the time it just stays stuck in blm 4. i'm confused?

only now all my blm's are reading 127? wth? and dancing around by two points. I had it set at an even integer of two for it's updates.

 

I think it has to be driving around... I started driving my car and datalogging and it started working again. ....

*sighs* if it's not one annoying personality trait with this car it is another... lol