cold start only thing left

[Black00Z28]

hey guys new to the forum, i understand this topic has been beaten to death over and over and i have done a ton of searching but i feel i am very close to having this car 100% and just need some insight on where i should go from here. i have a 2000 z28 it currently has a 6.0 lq4 block bored .30 over with speed pro flat tops ls2 rods and stock ls2 crank. cam is a 235/242 111ls with +2 advance, no power adders all n/a. the car is dialed in for when it is warmed up and drives amazing but the issue i have right now is cold start, a buddy of mine who is a little more fluent with hp tuners has been guiding me but we are having quite of a time getting this thing dialed in for cold start. when i go to start it, it will start up and idle at 1200 rpm where its supposed to be for maybe 2 seconds then all of a sudden stalls right out, doesn't sputter or surge just completely shuts off. then the only way to get it started again is to pedal it until its about 1/4 of the way warmed up and i can begin to let off slowly until it wants to idle on its own. if i let off to quickly it shuts right off. we tried adding more RAF but its still doing the same thing, i even tried adjusting the friction airflow delay because it was sitting at 4 cam rev so i upped it to 100 but it still needed me to pedal it just a little bit but caught itself better than before, but when i went to put it in gear it shut right off so i set it back to 4. can someone please take a look at my tune and see where we can start? 4-5-20_freshread_after_frumusa_14_Startup_air.hpt

[Black00Z28]

Anyone?

[Black00Z28]

Can anyone offer any advice?

[Po'Boy]

Do you have a log?

[Black00Z28]

Unfortunately I don’t at the moment I’m going to try to get one in the morning, I figured I could post the tune in the mean time to see if there was anything that stood out

[anniversaryss]

Unfortunately I don?t at the moment I?m going to try to get one in the morning, I figured I could post the tune in the mean time to see if there was anything that stood out

Where are you from. Frumusa is a shop semi local to me. Im assuming that's the name of the shop the car was tuned?

[Black00Z28]

I live in Brockport ny and Yes I had it to mike recently to try and get the cold start and wot done, the only thing that really got done was wot he said he couldn’t figure out the cold start issue. Car drives decent when warmed up but the cold start is horrible

[anniversaryss]

Im frkm buffalo, my buddy from brockport was there the other day getting his car done.

I can't view your tune without updating which i don't wanna do lol.

My car has similar cold start issues. It starts it hits a certain rpm and holds then i comes down and shuts off
If i hold the throttle and keep the rpms up for like 30 seconds it will come down to idle.

[Black00Z28]

hey guys sorry for the delay, i am uploading two logs the first log is from a cold start which actually the car was able to start up on its own without me pedaling the throttle which doesnt happen very often. I let it idle and get up to temp and that's where the second log comes in. When i go to put it in gear the car dies everytime, when I restart the car it surges and almost stalls but ends up catching itself. towards the end of second log i put it in gear and pedal it to see if it will idle on its own but still stalls out.

[Black00Z28]

Anyone have any ideas?

[kingtal0n]

I see it leaning out and dying. It needs tuning if the wideband is correct.

It could also be the maf sensor placement or leaking air. An air leak would lean out the engine and kill it under those same situations.

how bout just disable the maf and tune the ve table?

[kevin87turbot]

Anyone have any ideas?

Your IAC is way out of adjustment. It should be in the 40-60 range once warmed up. Yours is in the 150-160 range!
Give it at least 1.5 turns of the minimum idle screw to start with. Be careful not to go above 0.82V max on your TPS...that'll kick it out of the idle routine.

[Black00Z28]

We ended up lowering the idle rpm from 1050 to 950 and that for whatever reason brought the iac counts down to 100 which is what I have always heard is where you want it fully warmed up, also the tps voltage sits right around .63 at idle

[Po'Boy]

Did this take care of your cold start/run issue?

[Black00Z28]

I’m going to log another cold start in the morning to see what it does, we tackled getting the iac counts down and addressing the dieing once in gear, we added a couple grams of air to the airflow in gear which now it doesn’t die but you can hear the iac shoot open once you put in gear and it tries taking air back out, but we end up taking air out and that’s when it dies in gear again.

[kevin87turbot]

We ended up lowering the idle rpm from 1050 to 950 and that for whatever reason brought the iac counts down to 100 which is what I have always heard is where you want it fully warmed up, also the tps voltage sits right around .63 at idle

100 is still too high for the IAC count, but it's better than 150. If you'll open the throttle just a bit more, I'll bet the cold idle issue will be drastically improved.

Here's a link to a good write up...

http://www.gmtuners.com/tech/TPS_IAC.htm

[Black00Z28]

my question is if i open it more, wont that invite the " cruise control" effect when driving? i had that issue with the old crappy speed engineering throttle body before i put this nick williams 92 on it

[kevin87turbot]

my question is if i open it more, wont that invite the " cruise control" effect when driving? i had that issue with the old crappy speed engineering throttle body before i put this nick williams 92 on it

No it won't...as long as you disable the Throttle Cracker table.

[Black00Z28]

I’ll give the idle screw a shot and report back, if I start opening the blade with idle screw I’ll have to remove some of the base idle airflow correct?

[Midnite Magic]

hey guys new to the forum, i understand this topic has been beaten to death over and over and i have done a ton of searching but i feel i am very close to having this car 100% and just need some insight on where i should go from here. i have a 2000 z28 it currently has a 6.0 lq4 block bored .30 over with speed pro flat tops ls2 rods and stock ls2 crank. cam is a 235/242 111ls with +2 advance, no power adders all n/a. the car is dialed in for when it is warmed up and drives amazing but the issue i have right now is cold start, a buddy of mine who is a little more fluent with hp tuners has been guiding me but we are having quite of a time getting this thing dialed in for cold start. when i go to start it, it will start up and idle at 1200 rpm where its supposed to be for maybe 2 seconds then all of a sudden stalls right out, doesn't sputter or surge just completely shuts off. then the only way to get it started again is to pedal it until its about 1/4 of the way warmed up and i can begin to let off slowly until it wants to idle on its own. if i let off to quickly it shuts right off. we tried adding more RAF but its still doing the same thing, i even tried adjusting the friction airflow delay because it was sitting at 4 cam rev so i upped it to 100 but it still needed me to pedal it just a little bit but caught itself better than before, but when i went to put it in gear it shut right off so i set it back to 4. can someone please take a look at my tune and see where we can start? 4-5-20_freshread_after_frumusa_14_Startup_air.hpt

Mike Frumusa strikes again. That tune is trash MAF curve & VE table is a sad joke. Find a better tuner not someone who only does 3-4 wot pulls and is too busy boasting about tuning in the middle east