Justin96z28

Alright I know this has been beaten to death and believe me I've done my research and searched and read re-read and re-read some more.... I am needing some major help here. I have replaced my optispark 4times now, and I think I am going to be replacing it again.... So I have a AUTOZONE new unit (I KNOW SHOULD OF GOT DELCO) but I am on a budget and I will be doing a coil over in the near future. Anyway I am getting like a stumble/miss feeling from idle to 3000 then it clears up, sometimes even getting a back fire while downshifting. This opti unit has roughly 500miles on it. Prior to this unit I ran an ebay unit which was junk the bearing went to crap on startup, then got 2 different cardone reman HD unit and kept getting res. error codes. So I went and swapped and exchanged for a AZ new unit and now its not throwing any codes at all but like I said it feels as though it stumbles and misses on light throttle but at WOT it is fine. I am going nuts here now, I have replaced the coil with a new moroso unit, have a new ICM, new stock replacement wires from az (the coil wire already went bad so I put on a MSD coil wire already) new DENSO plugs, new maf, new opti, going to be replacing the O2's on monday with new DENSO units as well. If the o2's dont clear this up I am going to be putting on my MSD OVC wires that are new but wasnt going to use them because i just put new stock type wires on from AZ like I said. Oh has new injectors also 24's.. I am at my wits ends guys please please help me... Even swapped out the coolant sensor in the WP as I was reading this could also cause an issue... Please help me out guys I am going to be bald before I know it from this.. Also if anyone is in the Phila area within 50miles and could help me out with a datalog session I would really appreciate it. TY GUYS!!!

hrcslam

It is rare, but the cheap units are known to be pressed together wrong. If the rotor is slightly off it will change actual spark timing vs commanded. This is something to look for when you buy a cheap unit. Compare a known good one to the cheap one to make sure the rotor position to the drive position (the part the mates to the cam) is the same (correct) position in relation to each other. The PCM won't catch this as the electronics of it all will still work, but it'll be physically in the wrong position. But, I'm not so sure this is your problem.

Looking at your signature, you have a lot of mods that will need adjustment in the tune. Tuning over e-mail is difficult, and tuning for drivability is even harder. When you tune through the internet it's all about the numbers, but the numbers don't tell you everything. You also need to know how the engine likes the changes. No two engines will act the same, even if the build is identical and blue printed to each other, they'll still be slightly different in their tunes, and even more so for drivability.

First, you need to make sure your fuel injectors flow rate and voltage offsets are correct (see your other thread for where to find this information). Then you need to make sure the O2 sensors are calibrated (O2 delay, and correction tables) to the LT's. Basically you need to make sure the PCM is receiving the sensors information properly for their location and type. This includes the MAF.

I see you're running a ported MAF, that will need to be calibrated. Is the MAF still in the stock intake tubing, or do you have a CAI? In either case, the MAF needs calibrated too.

In my personal experience, and this isn't experienced by everyone, I noticed a big difference in drivability when I tuned my VE tables even in MAF mode. This is debatable, but just listing my experience. When in MAF mode, you don't NEED to tune the VE tables (again this is debatable), but in MAF mode the VE tables are your fail safe. If something causes the car to go SD (Speed Density; no MAF) it will fall back on the VE tables. If the VE tables are off, the car will run like crap (ask me how I know...., LOL).

Do you have $EE Hack? If so, try using that to analyze the tune and see what changes need to be made. I've tried using $EE Hack, but it keeps crashing on me (my old laptop crashed and my new one is Windows 10 and I forgot to set up the program for compatibility mode). So I've been analyzing my tunes with Scan9495. I'm going to try $EE Hack again later today to see how well it works (should be a ton easier) vs Scan9495. Once I have more experience with EE Hack, I can help you out better with that.

myltwon

iTrader: (1)

How does it run at initial startup?

Justin96z28

Runs great initial startup..... I am going to take the opti apart next week and put the AIP optical sensor in it along with the msd cap and rotor to see if there is any change...... Like I said the opti has maybe 500 miles on it... It was dyno tuned before but injectors have been changed I need to get a cable to log and learn to tune this beast..... Yes has CAI I have no idea if PCM4less calibrated the maf when they dyno tuned it but to be honest I never like the tune they did....

AdsoYo

iTrader: (1)

if you want I have a stock Mitsubishi optical sensor I'm trying to sell. I went 24x and don't need it anymore.

Justin96z28

Wat u trying to get for it? How many miles on it pm me

myltwon

iTrader: (1)

Honestly if it runs good at initial start up and wot, then that's when your car is in open loop mode. The pcm does not use information from the o2 sensors while in open loop. Because of this I would lean towards a faulty o2 sensor

Justin96z28

just waiting for the square to flat adapters and my new DENSO's go in got the 54" vette style ones I heard good things about the Bosch 13111's but honestly Bosch products besides injectors freak me out so I went with DENSO because I've had great success with all these products