luckyou03

iTrader: (8)

ok here's the history:

1st setup:
hotcam, shorty headers, catback, stock cat, stock tb
- got it tuned by pcmforless, ran great!

2nd upgrade:
still hotcam, 1.6rr, longtubes, no cats, true duals, 52mm tb
- ran the old tune(above), runs strong but pops/backfires when WOT. Drives normal except WOT.

Just got my new tune for the new mods and i can't even drive the car down the road.. It's been double checked by pcmforless, and emailed to me twice. i've loaded it 3 times with no driveable success. it dies, shutters, shakes and has no power.

I'm running the old tune right now to be able to drive the car. PCMforless said i have something mechanically wrong?

Here is a vid with the new tune: http://lt1engine.com/problem.mpg

I've replaced virtually every singe sensor with about 3-4 months run time on them. (02's,knock,water temp,pcv,new plugs,wires,opti). I am running the original tps, maf, iac, iat, map and evap.

btw i'm not throwing any engine service codes.

dhdenney

iTrader: (53)

You've added roller rockers to the mix. Do you have a way to monitor the amount of retard you're experiencing?

luckyou03

iTrader: (8)

i can hookup a laptop with pcmcomm.exe http://carputing.tripod.com/9495LT1Edit.htm . but i dont have any type of scan tool other than that.

Honda Hunter

iTrader: (8)

freescan. How can you have a mechanical problem when the car runs fine on the old tune?

blkchevyz

if you want i can take a look at both your old and your new tune.
shoot me a pm and i'll send you my email address.

luckyou03

iTrader: (8)

thats what i dont get!!!

Honda Hunter

iTrader: (8)

Are you posotive it runs fine with the old tune? Mabey he sent you the wrong file?

slowmofo

iTrader: (6)

sound like its just rich with the old tune, and the new tune is fubared

blkchevyz

what valve springs are you running?

luckyou03

iTrader: (8)

well i emailed him and he sent me an email back saying he checked it and i have some type of mechanical problem. i sent an email back saying i'm driving the car perfectly fine except for wot popping with the old tune. I haven't recieved a response.

I'm 100% sure the old tune works, because it's my daily driver and thats the tune in the car right now. I got him to email it twice, just in case he sent the wrong one, and i got the same results.

luckyou03

iTrader: (8)

lt4 springs with 1.6rr on lt4 hotcam, car starts to go on new tune, but then falls on it's face and dies, shakes.

blkchevyz

i was thinking you could be floating the valve making it pop and bang in wot.


i'll look at the tune when i get home

luckyou03

iTrader: (8)

i just figured i was popping because of the longtubes and no cats

Honda Hunter

iTrader: (8)

Couldnt hurt to rule it out.

blkchevyz

the long tubes and no cats would make it pop when you let off... but it shouldnt be popping under throttle.

luckyou03

iTrader: (8)

what causes valve float, do i need to go check my springs? yes as soon as i get it on it, it goes Bang Bang then takes off.

street demon2k3

iTrader: (3)

dont know if this matters but have you replaced your opti, or how many miles do you have on it? i had the same problem when i did the 230/236 cam and it ran fine with the tuning till it started to miss and pop when i got on it. replaced just about every ignition related component then found out my opti was shot? mine would run fine under light loads but when i would go WOT it would miss and pop but it would still keep pulling till i let off. finally after a few days it just started missing at all rpm's. dont really know if it helps but its worth a try.

luckyou03

iTrader: (8)

i installed this opti last august. if my opti is bad, i'm gonna burn it. we'll see see what blkchevyz says about to tune before i go replacing stuff.

luckyou03

iTrader: (8)

update! took the pc out in the garage ran the pcmcomm.exe scan tool. here are the results:

car off
Start up
car running 1 (open loop)
car running 2 (open loop)
car running 3 (open loop)
car running 4 (closed loop)
car off

as the car warmed up the right 02 stayed consistantly lower.

DeltaT

iTrader: (5)

Almost sounds like you are hitting an incorrectly set rev limiter... The rev limiter should be set for something like 200-300 over the point your cam really runs out of steam, which on the hot cam would be a setting like around 6300-6400.

Does it die as soon as you open the throttle all the way or do the revs have to climb to a certain point then it dies? That can be a hard point to find in a low gear - try 3rd at a moderately low speed and see if it is TPS dependent or RPM dependent.

Jim