Thanks for the info. It's tough getting this going. I pulled the plugs this morning and I thought one looked especially poor. I hooked them up on top of the intake and cranked the motor. One's spark was barely there and I thought I had the culprit. I pulled one of my other old plugs from the shelf and put it in and headed off to Advanced Auto to get a new set of plugs. It went downhill from there. Once again, it was stumbling along on 6 cylinders (if that). I got the plugs and, of course, some damned Subby WRX sees my intercooler grinning in the front and he thinks he's going to test my traction. At every light, I can barely take it off and keep the motor alive and the Subby rushes up on my *ss waiting for me to take off. Lol... good grief. I pulled the car into the garage and I have the fan on it, cooling her down before pulling the crossover, intermediate pipe then the plugs to replace them. I'm going to go ahead and swap the injectors to some 28# that I borrowed. I need to get the car running so I can get to/from work. I'll address the higher HP stuff later.

 

I think everyone knows that I don't like speed density tunes. On turbos the boost is nonlinear to engine rpm so that makes a Maf tune even more attractive.

Yes I know the Maf will max at about 450 rwhp. When it maxes it is relatively simple to just add fuel to the PE tables. It is easy to tune AFR at WOT with either method, however its all the area under the curve that the MAF is so good at.

Also the MAF actually reads airflow. Speed Density takes an educated guess based rpm, temp, and pressure. With boost you will get alot of spikes in airflow. Speed density will not adjust the fuel flow in these situations.

Also there is something to be said for keeping your engine controls and pcm as stock as possible. I believe that those GM union guys that have been building cars for 30+ years know what they are doing. If you take a look at Bryan Herters tune you will find that there are very few changes from the stock settings. Most of the good tuners keep it simple and so do I.

 

Hang in there. You'll figure it out. There are always some gremlins when replacing so many parts at once.

 

Take a zip tie and wrap around the opti harness to main harness plug. Go from end to end and pull it tight, this makes sure the plug doesn't back off any and lose connection. I've seen this happen on at least 4 cars, and this fixed it. Just something you can try.

Bad thing about PE and turbos, if I backed off the throttle to get traction, but was still in boost, it would kick it out of PE and lean out. This is one of the main reasons why I went with the 2 bar map sensor tune.

 

How this engine can chug along on 5 is a testament to the prowess of the computer management. Jeez.. this thing is kicking my *ss. Let me state what hardware I started out with last week..

Completely new forged shortblock put together by a guy that builds several of these for race cars.

New LTCC ignition system (still uses my stock Opti which was working fine), used set of Ls1 coils

Used 60# mototrons.

New Bret Bauer Cam kit

New Comp Cams lifters

New spark plugs

New plug wires

New pushrods

Prior Ported Lt1 heads

Custom Turbo tune by Bryan Herter of PCM4less.
=============================
Here's what I've changed in an effort to pin down what is making it miss on at least two cylinders.

2 new O2 sensors - result = no improvement

2 new sets of plugs - result = no improvement

Gone from Brians tune to a stock one and back in 29 reflashes to date-Result = occasional improvement in idle. Still misses when driving

Replaced all the Ls1 coils with ones from a working LS1 - result = No improvement.

Replaced the 60# mototrons with 28# from a buds LS1 - result = No improvement.

Rechecked the valve lash on the drivers side head. - = Result No improvement.

Took all the plugs out on the drivers side and laid the plug from that cylinder, using IT's own plug wire, on the valve cover. Cranked it over, they sparked just fine.

The last time I pulled the plugs, all the passenger side looked good, which is what the scanner was showing for O2 readings. The problematic drivers side had plugs that looked like the passenger side (clean) on cylinders 3 and 7. Cylinders 1 and 5 looked fouled. Given this revelation, I went and picked up new spark plugs and put them in. As SOON as I cranked it over, it was missing the very same way it was before I swapped the plugs! Thats when I swapped injectors. Imagine my disgust when after finishing that, reloading the turbo tune with the new injector constant, firing it up, as soon as it fired up, it misses the very same way. After getting it started and idling roughly, I went out to shake the wiring harness on the LTCC and coils to see if I had a wayward connection. No luck(except bad of course, lol)

I just called a rental place to rent another farking rental for a few weeks till I get this figured out. It's just sooooo weird!!! The passenger side is fine! It's getting fuel. It's getting spark. The valves were going up and down correctly when I was adjusting the valves. I can't think of what else it could be.

 

If you change the "%TPS for WOT" to 25% it will stay in PE mode while your lifting for traction.

 

Opti? Crossed Plug Wires? Cam/Opti Installed wrong? I would buy a cheap set of LT1 specific plug wires from Autozone and bypass the LTCC altogether.

 

Opti? = Maybe. I contacted Turbo Bob (Designer of LTCC) to see if he thought some aspect of signaling could cause this. No definitive response yet.

Crossed plug wires? = With the LTCC, you can't easily cross the plug wires since it's nearly COP (Coil on plug)

Cheap plug wires? = The LTCC has you ditch the stock coil and Ignition control module so I don't have that hardware to test with. I wish I did.

Tonight:
1. I will buy a timing light, establish TDC, mark the Harmonic Balancer, put the timing light on #1, then spin the motor over seeing where it sparks. Then put the timing light on #3, try that, then on and on to see if the spark is going out of phase. If that matches up correctly then...

2. I will swap in my spare PCM and see if that makes a difference. If it doesn't, then....

3. Test the injector connectors on #1 and #5 to see if they are staying on too long or not at all, etc. (although.. the plugs are very wet when pulled)

 

Correct, but then when I'm just driving around it will dump the extra fuel in, even if I'm not in boost, which would be BAD.

 

Looks like I may have isolated it. TurboBobs LTCC has a couple of LED's inside the housing for the processor. I'd PM'd Bob last night asking if he had any idea if the LTCC could play a role in this. He asked me to pull off the cover of the box and look at the LED's.
Upon "KEY ON", they go thru a bulb test and flash once. Then, when you crank, the green LEN *should* illuminate and stay on. Mine does. The red LED is for diagnostics. Here's what the .pdf file just told me....

Red LED flashes once = Cylinder Decode sequence error.

Red LED flashes twice = Wrong number of Hi Res Pulses counted between Lo-Res Rising edges.

Red LED flashes Three times = Wrong number of Hi Res Pulses counted during a High Lo-Res pulse or a Low Lo-Res Pulse.

Red LED flashes four times = EST (Electronic Spark Control) signal from PCM = missed pulse. Check connection to white wire.

Mine is flashing 3 times.

I've sent a PM to TurboBob to see if this means its wiring or time for a new OPTI.

 

Any TPS below 25% will be 14.7. 25% and above will be 11.5 AFR. It works well for me.

 

blower vs turbo car are completely different.

For instance, if I roll into the throttle say 50%, and it dumps in enough fuel for that full boost amount, but I'm only at zero vacuum, then it will bog and go 9.9 afr or richer.

Wanna know how I know, I've experiminted with all of this last fall, and on a turbo car the PE doesn't work nearly as well as a 2 bar tune!

 

I don't know why yours didn't work but there are lots of turbo guys with MAF tunes that run just fine.

Lets use your example. At 50% throttle on a turbo you could have 0 boost or 10pds. It doesn't matter how much boost your running(or if its linear to rpm) the MAF is going read the airflow and then add lets say 15% additional for PE. 15% of 0 boost is correct and 15% of 10 pds of boost is still correct. I can't figure how yours went so rich.

 

I guess I should mention the maf would max out VERY quickly so what you mentinon above won't work perfectly. I'm not saying it didn't work on my car, because it did, although it was just a rather harsh tune IMO. Although I should mention I'm very picky about my tuning.

A blower car vs turbo car are WAY different.

 

Well.... over nighted the Opti and a new Opti Pigtail and it was here to great me when I came home from work. Tested them before installing it by just hooking up the harness to the new one, turned on the key, spun the opti. The red blinking light on the LTCC was gone and I could hear the spark plugs sparking. Cool ... So I installed it. Then swapped the injectors back to the mototrons. Reflashed the PCM with Bryans tune and fired it up.
IT RUNS THE SAME G*D DAMNED WAY AS IT HAD!!!! Running on 6 cylinders at the most.
UNbelievable! This is so sad it's funny.
I tried relashing it with the timing advanced 2 degrees across the board since it starts so weakly. Doesn't matter.
Ill get a timing light tomorrow and see it that reveals anything.
The scanner says it's got 32 degrees at 850 rpm now. It did say 30 before I added the extra timing.