First off, I have no idea what happened. Been working on a new tune w/ the new blower. I know the VE table is a little outta whack but I was working on that when I realized I no longer have STFT. I have it set to enable STFT in open loop yet shows zero in the scanner.

Just a little history, sometimes when tuning the VE table I disable DFCO and COT but leave the stft enabled in open loop but command closed loop OFF in the scanner to turn off STFT. once I get the VE dialed in pretty close w/ RTT I uncheck the closed off command and continue my drive until I can smooth and reflash the tune. I dont know if this has something to do with my problem or not. I reflashed an older tune that I know had STFT working just for a sanity check. Still no STFT. I just found this problem out while returning from New Mexico the other day. I hope it's just a stupid mistake I made like checking the wrong box somewhere. I was also planning on swapping to an 01 pcm I had to take advantage of the newer OS. Was hoping in doing that I might also fix this problem. No luck!

I scanned for codes and found P0102, P0103 which are needed to run in SD.

and P0405 which I think I forgot to turn off in the new pcm for EGR but didnt have in the 99 pcm.

and P0748 seems to be trans pressure solenoid related. Might have something to do with the vacuum modulator and resistor?

Thanks,
Alex

 

Try setting your closed loop enable temps (ect vs IAT) to something you will reach. Now at 284. Here is a stock table.

185.00000 176.00274 167.00260 158.00246 149.00232 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204 131.00204

 

Ill give it a try but I had it set at 284 to keep it in open loop. I used the stft enable in open loop to make fueling compensations. It's worked fine that way up until a few days ago.

It's just weird I don't know if I inadvertently changed something or it's not flashing the open loop stft correctly.

 

p0748, i had trouble with it last night. Mine was because of a built tranny and a Stall. The higher stall speed is supposed to throw the pcm off???

 

It was because of my vacuum modulator. I forgot to set that and the egr code to no report w/ the new pcm. but I got that part fixed now. just no stft

 

Ive had a lil more progress on the HPTuner forum so I thought I'd post the link for anyone searching in the future.

http://www.hptuners.com/forum/showth...807#post136807

 

Problem Solved! was a loose connector for the narrowband signal from the LC1.

 

Admittedly not any type of expertise in the type of engine tuning that is obvious on this forum. However, hopefully I might get some help, insight and learn something!

I have had problems passing vehicle inspection due to "not ready" monitors. My 2011 Suburban 1500 has two lingering "not readies" - the evap and O2 sensors. Using an OBD II scan app, I'm not getting any signal (in %) about the Short Term Fuel Trim on both of the downstream sensors. One has n/a% and the other no value at all. Since there are no DTCs thrown, the mechanic simply says drive it more and do drive cycles. But I've gone to Big Bend and Hallettsville ( over 3000 miles in Texas) recently and have been doing drive cycles when I can - don't think driving more is going to fix it. Note that all the O2 sensor monitors and the LTFT's seem to be within normal ranges. The engine runs like a beast as I've recently had it fully tuned with plugs, wires, coils, etc. Mileage is over 140,000. Note that I have had the transmission rebuilt (and reprogrammed) and also use a V4 disabler on the OBDII port.
Any help appreciated

 

No downstream O2 sensor data?
No short term fuel trims?

Strange. Never heard of that. I wonder how the ECU is calculating fuel then? 🤔 Is it even going into closed loop?

The downstream O2 sensors are used for catalytic converter performance. I don't know if they are used to calculate fuel trims ( I don't think so.)

The EVAP being not ready is perhaps due to some sensor reporting wrong data? You'd need a better scanner with bidirectional capabilities to commands sensor actuate and monitor voltages to see if you have a bad one. There's only like 3 sensors on the EVAP. It's pretty basic, but finding the fault is often challenging.

 

Not sure there is anything wrong with any of the O2 sensors. The only strange outputs from the scanner are that the STFTs that are identified on both of the downstream sensors are not showing any data (in %'s). One shows n/a% and the other is totally blank. The "live" graphics on both are a blank screen. All other "monitor" stuff shows a live graphic.