Is your MAF de-screened?

 

Yes my MAF sensor is descreened.

 

Put the screen back and see how it runs.

 

I did as mentioned earlier and only tweaked my MAF tables down low for idle and just off idle.
For WOT the PE tables are definately where you want to be messing around. But if you have descreened the MAF the MAF tables will be off sligtly from the stock settings, See if you can find a reliable person with MAF tables for a descreened peice and then adjust low again for your idle (timing as well) and then adjust your PE for WOT.

If you could find a person that has the basic same mods motor wise as you that could help with the timing maps as well, that would probably help too.

 

can you send your bin file to vincentbergeron@yahoo.com and let me take a look at it.
when you say you going 100 mph and you runnig wot or are you running about 3000 rpms just cruising around, or does it do at 100 no matter what.

from the looks of your mods your not maxing out the injectors.

send it to me so i can look at the tune.

 

Well I got back to my car. Installed some 1.6:1 roller rockers and some other misc stuff. I'll get my most recent program off my laptop here for you. Thanks for your help!!!

Unfortunately, the car is really hard to start now. I did notice one thing that was probubly effecting my performance. After getting ahold of a fuel pressure guage I noticed there was only 38 psi on the fuel rail!!! Yikes. So I bumped that up to 45 psi. About that time I tried to retune a little for idle so my car would consistantly start w/ the new rockers and unfortunately, fried my PCM. I will not be able to test the new results for a while now. New PCM is on order

 

Got the new PCM in. I played around with it a bit. Starts like a charm. Tweeked the throttle body screw and got my IAC counts down. However at start up the engine revs to 1500 rpm then slowly drops to my set idle at 1k rpm. Why is that?

Next. With the stock MAF tables the engine sputters under load at 1k - 2k rpm. Then it starts retarding the timing at around 3500 rpm +. Lastly at around 5k rpm the engine cuts out.

So what are your guys' thoughts? Again thanks much for the help!

 

i sent the new bin file to your email. bet it works now.

let me know

 

Awesome... I'm going to look it over here before I got to bed and try it out first thing in the morning. I can't tell you how much I appreciate this! Thanks much!!

 

I CAN SHOW YOU WAHT IT WAS.

open tuner cat. open the file you sent me, then go to file click compare file, the choose the file i sent you back. now look at the all the boxes at the top of tunercat, the first is a little picture of a open folder, the last box on that row is the compare box, click that and it will turn the compare feature.

now open the ve tables both the of them (there are two) and look at the 95% and 100% colum, look at the difference. at 2000 rpms yours was zeroed out which was telling the pcm to cut all fuel thats why it was getting knock, becuase it started cutting fuel and getting lean, now click the compare button to turn the compare feature off. now your looking at the file you sent me. and you can see the acctual number in the table. the lower number in that table the more fuel the pcm will pull out. now do you really want to pull that much fuel out.

if you dont know wha tthe ve tables are they are the table that tell the pcm how efficeint the moter is at what rpm and map.

some say the ve tables are not used in the obd1 pcm, but if it fixes your problem its just more proof they are used

 

There was some light tuning done on the file I sent you. I tuned a little for idle. I did however, notice looking at other stock bin files mine differed quite a bit and didn't really have any explination as to why.

Today I test drove your tune. It helped the problem a lot. It doesn't lug while driving like 20-30 mph anymore. However, it still lugs and intermititanly hesitates (hickups whatever you might call it) while lugging in overdrive in the 1k rpm range at 45-60 mph or so. What should I do to fix that?

Next, when going WOT it runs perfectly all the way through 1st gear... then when it hits 2nd gear it still cuts out at around 5k rpm or so. After this I had to let out as I was running out of highway.

There was one additional question I had. I was looking at the % change AFR fuel / RPM at WOT (or whatever) and noticed you set it to a flatline value accross the board, what is the idea there? I actually have a couple other cc306 tunes, one is on a 383 and another w/ fully ported heads, would it be ok to use their table on that for a baseline?

Oh yes and I did notice your catch using the compair feature Nice one. I had actually wondered why that was so... however, my novice thinking dismissed it as something GM conjured up which was beyond me.

I really appreciate the help!!!

 

ok go to the % change rpm table, (first colum about 2/3s down) where i have 3 all across the board put in -1. right now your a/f ratio is 12.3 to 1 at wot. i did that becuse you were runing lean, more or less just extra precaution. put -1 there and that will get at about 12.8. 2.8 to 13.0 is where you will make most your power.

with the 306, in overdrive its going to surge a little at 1k rpms, the life of a cam, you can try to about 2 degrees timing if that doesnt help go into your ve tables and add a little fuel (increas that value) at the map and rpm by about 5 to 7 % and see if that helps.

ok i just looked at your file agian. your rev limiter is set at 5850 that needs to be at about 6500 and the car needs to shift at about 6300. ( just guessing) but that cam will make power at least to 6300 your prbably hitting the rev limit be fore you reach your mph shift point in 3rd. your car will not shift into 3rd gear until you hit 126 mph under wot (that what its programm to do) see table (kickdown mode up down shift points), to see. that probably why it was shuting down at 120 or so.

if you want me to do all that for you just let me no it will only take a few minutes.

try this lower that 3rd gear shift point to about 105 and see if it dont cut out. but you do need to raise your rev limiter up to at least 6500

vincent

 

Ok. Yeah, if you don't mind helping me with that file too that would be awesome. What I want to do is create one of my own doing what you said and compair it to the file you send me.

I also did a data run on all the stuff here that I spoke about in the text. It's huge though. I'm thinking I'll go and just get a WOT throttle run file and a lug file. Before I drove around for about 20 minutes and logged it all.

Also... I had hoped to wait until my car was tuned pretty solid before I upped the rev limmiter. Will it hurt anything not having a solid tune up to 5800 rpm (current rev limmiter I think) before I up the limmiter? I was trying to keep from hammering on my engine too hard. The bottom end is bone stock, just new berrings and whatnot w/ the lighter PM rods from a 96 LT1.

Thanks soooooo much for your help!!!

Matthew

 

Well I tried to make my own file. Unfortunately, I'm still a novice with tunercat. Not sure of where to modify the timing. Are you refering to the main spark tables RPM vrs. MAP... Just add 2 degrees across the MAP range from 1-2k rpm?

Next, I don't know for sure where the rev limmiter is set. I was looking in the constants table and saw fuel cut off and resume for 1 & 2 gears. Then I am really not sure where to set the shift points at.

Next off, if I were to modify the VE table... How would I blend in those modifications?

Lastly, the speeds to you mention seem quite high... Are you refering to a different set of gears? I've got 3.23 gears I believe. My car normally shifts into 3rd at about 80-90 mph.

Oh yes and with the rev limmiter... the guys I spoke with whom had that cam and stock heads told me 6700 is a good place to rev to with it. If I'm not mistaken my buddy told me it makes peak power on his car at 6500 w/ stock heads.

Hey.... THanks a TON for the help!! Do you do any instand messaging?

 

Oh one more thing. Car is hard to start. It will not start simply by turning key. When trying that it turns over and then quickly dies. I must tap the throttle with several blips just as it turns over to get it to keep from dieing.

oh yes and I just got a copy of datamaster. Thanks again!