ok, still haven't run it but it's suppossed to stop raining in a couple days, so it will be soon. I did burn a new tune and noticed I was wrong about LT1 Edit not having the AFR table, it is called "Open Loop Temp vs Load". If closed loop is disabled I wonder which would supercede which for fueling, the MAF or this AFR table? (probably the MAF)

Anyway, I noticed a couple things in my version of LT1 Edit that may allow me to run closed loop by keeping learning out of the surge range. There is a "minimum MAP for BLM update" and I raised it to 50 (MAP is basically KPA right?) to get learning out of the <50 KPA areas. There is also a "WOT BLM = 128, yes or no" that I have selected as "yes" .....I assume this is basically a BLM locker. I did not see anything that says anything about locking max and min to 128 in order to limit the integration to 5% ....nothing about locking max and min period.

When I cruise around the Scanmaster displays "MAP" readings of about 8 - 15 ...this is obviously not the same "MAP" as the BLM control MAP where it says "minimum MAP for BLM update" ......so .....just what is that "MAP" on the Scanmaster ...just a signal of some kind? ...it couldn't be KPA. I think the MAP values in the BLM control area are actually KPA, do I have this right?

My goal is to have a BLM matrix that doesn't allow learning at idle or really low load, but does allow learning at loads over 50 KPA, has anyone else done this by raising the "minumum MAP for BLM update"? Then I will lean down the MAF in the AFGS where you normally see at loads below 50 KPA until some surge comes back, then add a small increment of fuel to knock it out.

In spite of this, I still want to test open loop PE vs RPM, I will do that just to answer the question of this thread.

 

When you say "min and max blm to 128" are you talking about min and max temperature to enable? That's the only min and max I see related to the BLM's.

....I wish it would stop raining ....good Lord!

 

The reading you want is labeled MAP in freescan and in Datamaster I believe... it will read as a decimal. For example, 54kPa would read as 0.54 100 kPa would read as 1.00 and so on...

I figured that out when trying to get my decel fuel cutoff perfect... and it is.

That thing you mentioned about disabling learning under 50 kPa sounds promising. I am going to tinker with my car this weekend and see what I can find out... My car runs a lot smoother in open loop. I'm beginning to think that the MAF is a royal piece of ****, more trouble than it's worth for a race car especially.

 

If you've been messing with the MAF just remember that very small adjusments make big changes, that's been my experience anyway. I haven't even messed with decel fuel cutoff, what have you done to your advantage?

 

Finally got to drive the car and the verdict is in! It appears the PE vs RPM is being used during open loop based on this criteria: I added about 50% to the PE vs RPM table and leaned into the throttle about 2/3 or so and saw .988 mv's on the Scanmaster, haven't seen anything like that before ....it usually runs about .940 - .960

Also, this induced knock retard, I believe this may be "rich knock" which probably threw the O2 voltage lower than actual (probably 1000+).

Everyone think it's now safe to assume the PE vs RPM table is being used?

I played around with closed loop some too and found the following: I raised the minimum MAP for BLM update to 55 and adjusted the BLM matrix upward accordingly. This does in fact keep the long term BLM's at 128 anywhere lower than 55 MAP, however, the short term integrator was still able to trim fuel by about 7% ....which still induced surge. I did not lock the max and min temperature to values that would disable BLM's though....perhaps this will stop the integrator (doubtful).

Based on these findings I plan to run open loop and lean my MAF out in small increments until I see surge come back, then add fuel back until it goes away. I will still try to find a way to run closed loop without surge but it looks doubtful that it will work (much like Bunker and these other guys trying to run PE idle ....same thing happened to them, short term integrator kept kicking in anyway).

 

As of last Wednesday, I've run my car at 20 psi boost and 143 mph in the quarter in Open loop.

 

What makes you think this means open loop will provide adequate fuel for my setup? ....that must be pretty killer.

 

wow guys,
I have learned so much from reading just this one post about LT1 edit.

Please forgive me for reiterating but Im learning.

To tune for cruising, only the MAF table is altered? From what I read, the slope has to be as smooth as possible for a smooth ride all around. Also small changes in numbers still has big affects. Does increasing the numbers put in fuel? What do those large numbers mean in the MAF calibrate above the cells where inputs can done?

I believe Im running richer from my new mods of 1.6's and headers due to worse gas mileage.

Thanks for any help and sorry if im dragging you guys down.
Daniel
BTW, I thought open loop aka WOT ignores the 02's and just dumps fuel and for this one would adjust PE vs RPM and Temp...(temp I still dont understand).??

 

Dansean1 lol I wouldn't try to learn much from this thread in particular. I have stumbled my way through some tuning issues in this thread and there is a lot of disparity in the information presented. Adjust the MAF up for more fuel and down for less, there is only the one row of #'s you can change. You probably don't want to fool with that though, seriously. The only reason I'm tweaking it is that I have disabled closed loop to beat surge. This makes it run richer than I really need to so I'm leaning it down in small increments until I see surge come back and then I'll add fuel back to knock it out. I made a full point difference in the Open Loop AFR vs Coolant table and it made no difference at all.

Anyway, your minor mods shouldn't justify a need for tuning changes. The drop in MPG may be due to an exhaust leak before the O2's. I would say the main things you may want to change in the tuning is leaner fuel in the PE vs RPM table since the stock tuning is pig rich at WOT regardless. To give you an idea of how rich it really is, my supercharger tuning is actually much leaner than stock up until the really high revs. The stock tuning is especially overly rich from ~4,000 - 5,500 to protect the warranty. If you're leaking exhaust before your O2's they are reading leaner than you're really running, and adding fuel to compensate for a lean condition that doesn't really exist. I highly suspect that since you've recently installed headers.

At WOT the PCM does ignore the O2's but unless you have the BLM at WOT locked at 128 it can add extra fuel if the last calculation before going into WOT was lean. This is just another fuel safety net from the factory to guard against low octane users/abusers, it can't subtact fuel at WOT, it can either add it or leave it alone depending on the last calculation before entering PE mode.

 

Charlie, the DFCO is crucial and I can't believe it never got adjusted before. What you need to do is log the car and see what range of kPa values you get on decel in say third gear. Bring the car up to 4000 rpm and let it decel all the way to 1400 (stock turnoff point). The lowest kPa value (close to 1400 rpm) will be you DFCO cutoff and the highest kPa value (right when you start decelling, ie the most vacuum) will be the DFCO turnon point. Enter those numbers and take it for a ride and adjust further if necessary. With a loud exhaust system you can identify the exact moment that the fuel cutoff turns on. You can also adjust the delay but I find that one second after closed throttle (stock) works fine. You will find those in the constants menu. There are DFCO tables but I have left them alone.

I still haven't tried the PE vs. RPM in open loop on my car. I will try this weekend. I found out something very interesting... I think that a couple of loose electrical connections may have been causing my spark/surging issues. You should try beefing up the block to chassis ground, the battery to chassis ground, and the alternator to battery + cable. Who knows maybe you have something similar going on that I did.

 

Sorry but I'm not with you. What is "crucial" about messing with the DFCO? What am I trying to accomplish by playing with it? ....lost on this one lol ..

 

This thread has really enlightened me quite a bit.

What I dont understand is the BLM's and 128 numbers people refer to??? I dont think I have an exhaust leak...I suspect a slight miss, actually...sometimes a surge at idle at a red light, when I let off the gas slightly. Its not all the time though.

Those MAF #'s in the MAF calibrate table look really odd. They are decimals, so if one were to tune that, to adjust fuel would one adjust whole numbers or decimals? If I remember right, the numbers going in to the thousandths; Are adjusts suppose to be really small?

I heard maybe one could verify for me...are LT1's only tuned at WOT, hence PE vs Temp or RPM, no real cruise tables?

Hypothetically...if i were to rent dyno time...how does one know whether they should to adjust PE vs Temp or RPM?

Anyone mess the A4 trans tables such as torque converter lockup and line pressure per shift and rpm?

Sorry for all the questions but you guys are knowledgeable and being nice about sharing knowledge.

Daniel

 

I turned my DFCO off. I didn't like it kicking in and dropping my rpms between shifts and on low speed decels. I tweeked it for my cam but still didn't like it. Gone now.

I don't see why you guys are messing with your MAF Table's to lean or richen things in open loop. It is much easier for me to adjust it using the "Open Loop AFR vs Coolant Temp vs MAP table." I use tunercat for OBD2 though.

 

The stock DFCO min. MPH is 30, that's not that low... The car decels MUCH smoother with the fuel cutoff on. The DFCO does not kick in between shifts, the MAP range is not the same as the decel range.

 

Mine was set to come on above 1700 rpm and below 43 KPA which when you let off the throttle to shift would cause DFCO to kick in. I couldn't change the delay with tunercat.

Either way it is definitely not "crucial" because I have not used it for months and I get 25 mpg highway. I like the way my cam cruises when I let off the throttle at cruise speeds.

I am subscribing to this thread to find out how your open loop tunes turn out. Let us know how your driveability and gas mileage change. Thanks