since the weather started clearing up recently i went to the storage and fired up the blazer. ill get started with the specs...

3.4L 660
T5
p&p'ed heads and intake with 4.3tb
crane solid flat tappet cam .493/.512 lift and 300*adv duration
hooker longtubes with 2.5" O/R h-pipe

idles really well at 800 rpm and pulls about 40-50 kpa in vacuum. before i threw it in storage last year i got the tune ok but with a few issues.*edit* occasionally it bounces off the stall saver too.

idle is pig rich, and since the O2 doesnt stay hot enough at idle i have to tune it in open loop. i need to know what to adjust to lean it out a bit. im using the "7747-minesort.ecu" (from sixshooter) mask with the MPAB bcc.

also, when im cruising at part throttle, the truck is bucking/surging. it feels like im in a rocking chair lol. at WOT it pulls just fine. im wondering if its the throttle follower. any ideas? in the mask im using there doesnt seem to be a switch for manual/auto tranny. unless there is but i dont know what im looking at. which bit do i have to check for manual? thankies!!!

 

Going to be a lot of tuning with that cam... Main VE table to reduce fuel at idle would be a start since a stock motor idles closer to 20-30 MAP

 

i have the main VE table pretty close to where it needs to be. i just need to know which parameters to adjust for OPEN loop idle.

 

Well there's usually more than one way to skin a cat, here's my way.

If you have TunerPro and using a $42 xdf? Then in Scalars there's a "Minimum Coolant Temp for Closed Loop" Rasie that all the way up, that will keep you out of closed loop till 255 degrees. Pretty safe to say it will be open loop till you overheat...

 

yes if you set temp high as stated you will lock OL. I believe 7747 $42 has a OL A/F rpm vs map table. That table used from when choke times out till engine temp hits 165fF. hen CL takes over with VE tables.

 

7747-minesort.xdf is the mask. min temp for CL is maxxed at 255. i just need to know which parameters adjust fueling in open loop. what would be causing it to surge while cruising at part throttle? almost feels like the throttle follower is active while in part throttle. WOT is perfect, no surging at all. any ideas?

 

surging is lean. check your data log for IAC movement(TF routines). IAC should not vary that much cruising. Did you find OL table?

I was 0L one season. Gas mileage was poor like 20% less. I would add a heated 02 sensor and run CL. But then again that cam may require OL. Not sure. I deally run OL idle and OL <15 MPH but $42 I dont recall supports that.
EBL does however. I run OL idle and OL <15 mph. Cured my idle issues.

also consider making all the SA cells around the cell you idle in the same SA. that was it wont affect idle if it moves within cells.

 

yes, im looking at;

O/L AFR vs. temp
and
cold AFR vs. vac KPA

*edit* idle is great, just really fat. i just want to lean it out a bit. i did have a heated O2 on there last year but blew it out when i installed the long tubes. revved the engine and backfired and the O2 was toast. i put a single wire on there and now it doesnt get hot eonough to run C/L. once it heats up enough at cruising speeds the blms and ints are 126-128. so i think the VE tables are dialed in pretty close. when it surges it almost feels like it breaks up and smooths out. iirc i was looking at the IAC steps and they were fluctuating. i have winaldl and i need to figure out how to get it into excel spreadsheet.

*edit again* i just remembered that when im at cruising speeds, the engine surges when i push in the clutch. say im at 35mph, i push in the clutch and the engine will surge from ~800 rpms to ~2000rpms until i get under 10mph then it settles in at 800rpms. not sure what to adjust here.

 

bump

 

i have not looked at a $42 foer quite a while.

This one "O/L AFR vs. temp " I believe is used when car is cold start and moved off choke A/F.

this one " cold AFR vs. vac KPA" might be a modifier based on vac? not sure"

Can you locate a tble for OL that is x and y axis RPM vs MAP where values are like 14.3/14.7 or so?

If not then I would enrichen in baby steps the "O/L AFR vs. temp" say 5% to start and see hopw car responds. If you are OL then the BPC I believe will affect the A/F. A smaaler BPC will suggest to ECU that the injectors or FP is large and vice versa for larger BPC. Increasing BPC may enrichen A/F globally as well.

 

i leaned it out (using the o/l afr vs. temp) and it seemed to help but im not completley sure if it did lean out. the garage was already smokey lol. ive calculated my BPC for the 55# injectors andf 25 psi of fuel pressure and its at 72 right now. my blms are already pretty much dead on and id hate to recalculate them if i dont have to. what would cause the engine to surge when i push the clutch in at cruising speeds? it idles good under 10mph

 

can someone tell me which flags should be set or not for manual trans? and heres the tables for fuel as well.

 

wow no ideas?

 

I didn't see any in your pictures but usually anything with TCC is of no use. Have you tried to find a manual bin file?

 

is MPAB a manual bin?

 

is there another forum out there that can help?

 

I have not used a 7747 for years but in flags there may be one for TCC lock up. In my logs of my manual trans vehicle it always shows converter as locked up.

Surging is usually lean condition.

A tip is to post those specific questions in a seperate thread. I bet you will get some better answers.

Do you have EGR? If not it needs to be disabled in tune.