2013 Turbo GMC Denali not Entering PE Mode Conistantly

[bobbybanshee_2000]

I don't have a datalog to post so please just take my word for it. The truck is running a Trick Performance Turbo System, I've have looked over everything many times and cannot see anything I may have overlooked. Figured I would post it up to get a fresh pair of eyes to glance it over to see if I'm missing something. The truck will not always enter PE mode, not sure if its a timer or something I'm not seeing. Brad Turbo Denali 9-16-15.hpt

[schpenxel]

It's a long shot.. but I saw something the other day where a guy was having problems with PE on a Tahoe I think it was. It was somehow related to the flex fuel system he thought.

Have you tried disabling flex fuel to see if that helps? It's under fuel-->open/closed loop, flex fuel enabled. Change to disabled and try it

Total guess but worth a shot IMO.

[bobbybanshee_2000]

It's a long shot.. but I saw something the other day where a guy was having problems with PE on a Tahoe I think it was. It was somehow related to the flex fuel system he thought.

Have you tried disabling flex fuel to see if that helps? It's under fuel-->open/closed loop, flex fuel enabled. Change to disabled and try it

Total guess but worth a shot IMO.

I'll give it a shot but I hate to do that because we actually use the flex fuel quite a bit. Truck runs E85 whenever its local and if he ever drives it out of town he switches to pump gas.

[Area47]

use the map trigger instead of a tps trigger.

[bobbybanshee_2000]

use the map trigger instead of a tps trigger.

I am using the map, I have the tps trigger set really low and the map I have set to a point where i want to enter PE at approximately 1-1.5 psi of boost, E85 has saved this truck's life a few times I'm sure, because about 30-40% of the time we will cruise right past the map trigger and it will not enter PE.

[cesar]

get rid of the rpm delay,and lower the map enable kpa, try maxxing out the demand tables..besides that no clue

[10_SS]

GM performance cars (ZL1) enable PE by TPS... they set low MAP enter value of like 15kpa. In my experience, TPS is WAY faster to enter PE.. MAP is delayed for whatever reason, and since TPS opens first, then MAP responds second, TPS is safer. On my 2010 Camaro the logger PID is called "PE TPS". Using MAP at 95kpa for me, at throttle tip in, I would see 150kpa and still no PE fuel or change in Commanded AFR. This is fixed using TPS. You can change it by RPM, so you could set a higher TPS for low RPM, and lower TPS for high RPM.

I know trucks have more of a delay so you may always have slower PE response... my stock GM 8.1L in a 30ft RV delays like 20-30 seconds before entering PE at WOT. Seems like once I get it in PE, it's quick to re-enter PE... almost like it calculates cylinder air temp or valve temp, and that's what it uses to decide when to enter PE fuel for cooling. Crazy.

[02Ls1]

disable the flex fuel tab on fuel open and close loop.

It happen to me and that help.

[Area47]

the last turbo truck setup i did i set the map kpa to 120. tps to zero above 1500. no hyst, or adders, delay set to 10 rpm. enrich rate to 1.0. hits pe every single time without fail or delay. last supercharged camaro i did, it was set up this exact same way and never had an issue.

I am simply offering a way to get to work when all others have failed. Tps changes with load and gear. 50% in first is not the same as 50% in 4th.

[=fast=]

Not trying to high jack this thread but I have a question related to the flex fuel.
I'm about to finish my truck 2010 5.3 with a 76mm turbo kit.m, boost cam etc..

Ok I have always tune my truck in MAF open loop, this one it's flex fuel I will be running at least 12 lbs of boost, after I finish tuning it I will turn back my LTFT and back to MAF only in close loop. If this truck its tune correctly on 93 octane can I pump e85 and I won't have problems with the airfue? I seen files where on the stoich airfuel ratio they insert 14:67 across the table, I don't think that will work with e85.

[bobbybanshee_2000]

I should get this truck back for more testing soon, I may also just convert to 2 bar for better controllability of the fuel. I'll aproach this a few different ways before I swap just to find out what will work for future reference. To =fast= if you set the stoich values to 14.67 across the board the flex fuel switch will not work. It's best to leave that stock in almost all cases. Only time I have ever changed it is when someone brought me a truck with a faulty flex fuel switch. It was trying to run like 10.2 stoich on unleaded fuel so I disabled the flex fuel switch and forced it to a set value to straighten up fuel trims on a basically stock truck.

[=fast=]

Ok Bobby so just to be sure, after I tune it on 93 octane and leave my airfuel around 11:2 at WOT, MAF on close loop I can pump e85 and I should see around 11:2 at WOT on e85?

Now can It work on MAF open loop? I just want to know because sometimes there's e85 and sometimes they don't have.

All this its with the stoich table stock.

[bobbybanshee_2000]

Ok Bobby so just to be sure, after I tune it on 93 octane and leave my airfuel around 11:2 at WOT, MAF on close loop I can pump e85 and I should see around 11:2 at WOT on e85?

Now can It work on MAF open loop? I just want to know because sometimes there's e85 and sometimes they don't have.

All this its with the stoich table stock.

Yes as long as your flex fuel switch is still enabled, and you have the stoich table set at the factory flex fuel settings, and your truck is a flex fuel compatable truck, then if you set 11.2 it should adjust stoich on its own when you switch fuels and will still be 11.2, keep in mind though that based on what I have seen it takes about 15 or so minutes of driving for afterwards for the flex fuel switch to finish the adjustment. So just be cautious before you go smash the throttle after a flex fuel fill up, also keep in mind when setting up your timing tables that you probably wont end up at e85 since the tank wasn't completely empty, so you don't need to go as aggressive on timing as you could.

[schpenxel]

Wonder if the delay is from the sensor itself? There's also a field about how long to delay changing over, something about the amount of fuel in the lines from the sensor to the engine.

Using one of the flex fuel tricker boxes from DSteck ethanol content and associated settings can be made to update nearly instantly (uses flex fuel input to manipulate ignition timing/AFR/etc.) so I think it's either the sensor itself or the fuel volume delay setting.

"Delay Volume"
and
"Transition Volume"