Need help. Tune and data log inside. Issues with 2bar/3bar OS

[stealth2669]

I'll try to keep this sweet and simple w/o explaining or adding more than needed. I built a turbo setup for my 04 silverado with SD80lb injectors, no O2 sensors, I have a wideband. (no pro version for wb datalogging) I originally had issues getting it to run at all on a 3 bar map sensor and 3 bar OS. The truck would fire up and stall, fire up and stall. I have the greg banish dvds and injector info. After trying all sorts of variables, none of which worked, I put the stock map sensor in. Mind you it was still in 3 bar OS and the truck fired right up and idled. Obviously it wasn't right but it ran. So I switched to 1 bar SD os with no issues was able to rtt tune and get a feel for it. I ordered a 2 bar gm map thinking that was my issue. After installing the new map and 2bar OS it would fire up and stall again. A friend told me the pcm didn't take the tune so I falshed back to stock and tried to flash back to 2bar OS. Bam it ran good on the 2 bar OS but it was really rich at idle 11:1 then I took it for a drive and under any load it was ultra lean. When I RTT my VE inputs wouldn't do a thing, like they did with 1bar OS, so I tried flashing in VE calibrations and still nothing changed from the original base. I even went so far to write entire and still no changes. So seeing that it wasn't working I thought possibly flashing back to stock tune then back into the 2bar OS again would solve my problems. Now ON THE EXACT SAME TUNE it won't run, it'll fire up and stall fire up and stall. If I flash in the original 2 bar OS w/ stock VE table and change nothing else(ALL STOCK PARAMETERS MAF is NOT disabled) it'll fire up and run, it's uber rich 9.8:1, so I shut if off. If I change anything in the tune the truck won't run. Fire up and stall. Even to the same variables that it drove around the block on earlier... I'm at a complete loss. Any help would be appreciated. working 2 Bar OS.hpt first drive.hpl Tune and data log

[stealth2669]

Would anybody mind looking at the tune and letting me know if anything is out of the norm or a possibility for causing my issues. I just don't get it. 7 days of torture messing with this thus far.

[mecanicman]

List all the mods to the truck. Is it a 4.8 manual transmission? Do you have manifold(boost) referanced fuel pressure regulator? Which map is currently installed? ect. I can see the likely cause of your starting problem and will put a file together for you when list your mods.

[stealth2669]

100% stock long block, 5 speed manual, throttle by wire ETC, walbro 450, stock returnless 58psi fuel system, 72mm turbo, FMIC, gm 12615136 2 bar map, IAT in old purge valve location on manifold and currently no O2 sensors. I think that covers everything. I greatly appreciate the response and potential help.

[mecanicman]

Its going to be very difficult to tune with no 02 sensors and wideband not hooked into hpt. I suggest you try wire it in through ac or fuel tank pressure. I dont think you will be able to get those sd80 to idle at stoich on the 4.8, they are to big. Your o/l f/a table is all 1's, I dont know how rich it is now but may be hard to start cold like that. May want to copy stock values back up to 176 degrees, I left it how you had it. Give this a try, your file, so just write calibration.

[stealth2669]

Wow. Thanks much! I'll let you know the outcome here shortly. I was unaware you're able to log via another sensor input. I'll surely be doing that if I can find the appropriate info. I'd like to keep my a/c operational so hopefully I can use the fuel tank pressure input. Again thank you very much.

[5FDP]

I used the EGR on my 06 sierra, was very easy to setup. Wire into pin 55 and 41 on the blue connector. 55 is volts/power and 41 is the ground. Then setting up a user defined pid was needed to read it out.

[stealth2669]

^^I'm from minnesota as well, hopefully I can figure this out before snow flies, lol. My truck doesn't have egr and I know where the fuel tank pressure sensor wire is at so I think that is my best bet. Thanks for the input though. I'm incredibly intrigued by this and am currently finding what I need to do it.

[5FDP]

No trucks after like 2001 had EGR, but it's still there in the tune. All you have to do is wire it up and enable the EGR in the tune to make it work.

[5FDP]

http://www.hptuners.com/forum/showth...ight=part+deux

Read through this to give you an idea.

[stealth2669]

Thanks for the input. I got the wideband working via the fuel pressure sensor but I can't get the "scale" correct. At say 12.5afr they both show the same but at any other value they increasingly get further off from one another.

mecanicman: I also tried the modifications to the tune you made it it wouldn't idle. I messed with it a little and didn't have any luck. I made some changes to mine and can get it running but what I don't get is changes to the VE table do nothing. Also on startup its ultra lean 20:1 afr as coolant temp begins to rise it begins to richen up around 17.5:1 it'll idle on its own by the time it reaches op temp its at 11:1 afr. I don't get it at all. When I had it on 1bar OS a while back I could get it to idle great with these injectors and RTT worked. Now it seems like no matter what I do I can't get it to accept my values. I've flashed back and forth from stock to 2 bar several times with no success. I'm truely at a loss.

[mecanicman]

So as I stated you need to fix the ol table. Here is file with it done. You may have to feather throttle to keep it running. You need to have code 101, 102, or 103 set. Keep checking codes and dont clear them. Once code is set you should be good. I think this is why your adjustments are not working.

[stealth2669]

Well I have an update. To make a long story short I couldn't get the maf to fail so my buddy said well maybe it's because of the iat(seeing they're in the same connector) so I unplugged the iat and it fired right up and everything works as it should. I plugged the iat back in while it was running and it instantly stalled. With the key on ignition off, cold engine, the iat showed a 2 degree difference from the coolant temp sensor. I also quadruple checked the wires I pulled from the maf harness, they were black and tan, according to everything i've found those are the iat wires. I don't know what the deal is but my issue appears to be cured... minus not having a iat anymore. I want to say THANK YOU!! I really appreciate those that came in and wanted to help.

[stealth2669]

I know this is entirely different but now when I get into any boost I get "reduced power mode" and the truck stalls. Several people said the predicted airflow needs to be changed but I can't find a table for predicted airflow... any ideas?

[mecanicman]

Calculated air mass vs tps vs rpm 1514 error table in engine diagnostics under general

Nothing wrong with your iat in logs, your just to lean and unplugging the iat makes it show -32 and super rich. Did you try the last file I posted?

[stealth2669]

I agree mecanicman that's why I never suspected the iat. Yes I did try your tune and the truck wouldn't start it also wouldn't start on my other tunes that it previously ran on. As soon as I unplug it, it runs instantly if I plug it in while running instant stall. I'm just as surprised as you. And I have my afr dialed to a perfect 14.7:1 now with no issues. I thought reading -32 would skew the tune as well but it certainly doesn't appear to be doing that. It began to down pour shortly after my test drive so I didn't get much driving in. I'm going to take it to work today and do some more data logging. I also got my afr pid calibrated really close. Under 12:1 afr it reads .1 lean compared to my gauge but everywhere else it appears to be nuts on. Thanks again for the help.

[Mudweizer]

Isn't a 1 bar map sensor wired different then a 3 bar map sensor?

[stealth2669]

Not really. If you match wires abc from the 3 bar to abc on the stocker they're not. I also double checked that. Regardless the gm 2 bar I have plugs directly into the stock location with the stock pig tail.