My car currently has the '165 ecu and I did some logging with Craig Moates software. I attached some images of the log with the car idling, I cut the image short because the data is the same all the way through. From what I read, BLM's are what the main target is when trying to get the ideal tune (correct me if Im wrong). I've attached some pics of the log and as you can see my BLM's are 128 all the way across the board. I removed the maf "screens" so I am assuming the engine is currently running lean. What tables need to be changed to achieve the ideal tune for idle and why?

I am trying my best to learn this tuning stuff, so if at all possible, point me in the right direction with some explanation instead of throwing the answers to me.

EDIT: The logging was done in closed loop

Thanks in advance

Jeff

 

2 -

 

3 -

 

Last one -

Any suggestions?

 

Well, first of all, 128 for BLMs at idle or part throotle (driving around easy) is perfect. That is your target.

But, I am confused. You stated the you removed the MAF sensor and that you have the 165 ECU. How does the engine run with no MAF when the 165 ECU is a MAF ECU setup?

How would the ECU ever know how much air is going into the engine?

I have not been on this board for a bit, so maybe I'm missing something.

 

Your BLMs are locked at 128 because you are probably still in open loop operation(look at your AFR). The car hasn't had a chance to warm up. The closed loop flag should read 1 if closed loop is enabled and only then will you get feedback worth anything to tune by.

I too wonder how you removed the MAF from a MAF car especially since their is a MAF rate reported back!!!

 

Could it be that the removal of the MAF will keep the ECM in open loop mode and BLMs at 128?????

Yea, I had a hunch that the BLMs at 128 was too good to be true.

 

Removing the MAF forces N-Alpha mode. ECM creates an airflow term from TPS & RPM.

RBob.

 

Sorry about the mix up guys, what I meant to say was I removed the MAF "screens". I assumed that I was in closed loop in the log I posted because I had been running the car for about 8-10 minutes prior. Me thinking that I didnt run the car long enough for it to enter Closed Loop, I took the car out for a spin around noon for about ~20 mins and came back to do another log. As it turns out, I was STILL in open loop... So I went into the prom settings and looked into Closed loop data they are as follows:

* Hot O2 Closed Loop Timer = 30 seconds

* Warm O2 Closed Loop Timer = 160 seconds

* Cold O2 Closed Loop Timer = 300 seconds

* Closed Loop Fuel Enable Coolant Temp = 25.25* Cel.

Could my O2 sensor be bad? BTW, I have no idea if driving in open loop could have some effect on gas milage, but I am currently seeing about 165 - 180 miles on a full tank.

Mind you in addition to removing the MAF screens, I also removed the smog equipment and the cat. converter, also running headers with no AIR tubes.

What do you guys think?

Jeff

 

Based on the O2 voltage in the data scans the ECM is not getting a accurate signal from the O2. If you have the factory unheated O2 at the collector then there is a good chance that it is not getting warm enough to allow closed loop.

 

I suggest getting a 3 wire heated o2 sensor for a 1992 Chevy Astro Van vin code Z.

 

i find that when i go on tuning drives, i need to wait at LEAST 20 minutes, preferrably more like 25, before I start paying any serious attention to the data logs. it's only after the car is fully and thoroughly at temperature do things start becoming consistent and repeatable.

 

First off, thank you everyone for responding and your help.

Ok yesterday I decided to just go ahead and replace the o2 sensor reguardless if it being the culprite. As I was replacing the old sensor, what a suprise! it was broken in half. All this time I've been driving in Open Loop.

Anyway, with the new sensor in, I finally got the car to run in closed loop so I did some scanning and data logging of the car idling in neutral. I had BLMs of 119 and INT of 123, indicating that is was running, hrrrmmm... rich? Correct me if Im wrong.

After 5 or so chips of claibrating the MAF, it seems as though I sorta nailed the BLMs to 128. (I think its begginners luck ) Here is a link the log:

Idle in Park (Closed Loop)

Could it use more tuning or is that okay?

I am currently using Craig Moates software to do the scanning/logging, I have a question that needs to be clarified. When looking at the log, there are 3 BLM related tables next to eachother which are:

* BLM or coarse fuel corr

* INT value

* Fine fuel correction

Which of the tables are used to factor in tuning the BLMs?

Mucho Thanks in advance

Jeff