Post rebuild issues

[swathdiver]

2011 Denali XL with Flex Fuel

Thank you, you're fuel trims look ok as does your fuel pressure. While idling, does the fuel pressure vary much from 42-43 psi? How about while driving or if you floor it?

To see the alcohol content, you have to create a custom PID unless you have it in your master list. Those Evap cycles take some time to pass without trouble codes popping up.

If you live in Florida, stop by the house and my daughters will put our Tech-2 on it for you!

 

[tkdgirl]

Okay... I'm gonna be "that guy"... PLEASE don't use the term "turn over" here, especially in this context. It's really confusing and contradicting. It slows down the helping process when we have to ask for clarification and wait for a response before we can proceed. In a thread discussing if the key is being turned, or if the starter turning, or if the engine's crankshaft turning, etc., just say if it cranks (as it should when you turn the key) and if it starts ("fires" up and runs on its own). If anything, it's half the words to type. I don't mean to sound cranky (or is it turn overy?). Just wanna help get this figured out as accurately and efficiently as possible.

So, when you hold the pedal to the floor and crank the engine, it's not supposed to start. This is a factory function called "Clear Flood Mode". It stops the injectors and spark plugs from firing. It's to pump excess fuel from the cylinders should they become flooded for whatever reason. The idea was to test if you had a faulty injector(s) leaking down and flooding a cylinder(s) when it was parked. In addition to the wet fuel dousing the spark, this would also cause the fuel system to not be pressurized upon startup, causing a hard start (extended cranking) condition. As Fless mentioned, the EVAP purge system is another source for excess fueling to occur.

I assume the problem is pretty consistent, especially after it sits parked over night. Tomorrow morning, before you turn that key (leave yourself a note if you have to!), hold the pedal to the floor and crank it for ten seconds again, release the key, release the pedal, then crank it to start as normal. Hopefully it'll start and run normally. There may be a slight stutter, but it should still be a definite difference. Trying to get consistent test results here to narrow down the possible causes.

Did everything you outlined. It started but very slow and once it did start, the idle was very rough and the car shook a bit.

 

[tkdgirl]

Thank you, you're fuel trims look ok as does your fuel pressure. While idling, does the fuel pressure vary much from 42-43 psi? How about while driving or if you floor it?

To see the alcohol content, you have to create a custom PID unless you have it in your master list. Those Evap cycles take some time to pass without trouble codes popping up.

If you live in Florida, stop by the house and my daughters will put our Tech-2 on it for you!

Thank you for the offer! I'm way up here in Michigan.

 

[tkdgirl]

And this just happened..WTF is going on. Is it time to get rid of the tune?

 

[Fless]

If the engine coolant temp (ECT) sensor is not reporting properly, or there's something wrong with the circuit, that could very well be the cause of your hard start.

Eric O posted one recently and shows the diag:

 

[tkdgirl]

If the engine coolant temp (ECT) sensor is not reporting properly, or there's something wrong with the circuit, that could very well be the cause of your hard start.

Eric O posted one recently and shows the diag:

I suspect you're right. Now that the ECT is off, it starts just fine. Where is this located on the 2011 denali? Think I might be able to replace it.

 

[Fless]

You may want to look at live data first to see what it's reporting, cold and hot.

IIRC it's on the driver's side of the head or block, very near the front. Maybe someone else has a pic.

 

[Rocket Man]

kinda.. but there's ON as well. that sometime needs to be explained as well.

to me, turning the ignition ON, is just the first key click. dash lights up. but some people call ON the engine actually running. these are usually new to understanding cars and think of the ignition switch on a car like a light switch in their house. I turned my light switch on but my light didn't come on. they think of cars the same way. not the extra steps that a car needs to start an engine. and then these new electric cars which you do just hit the on button complicated even more. whole they go thru a while sub routine to check for high voltage isolation and stuff. plus those you hit the start button to turn them on, but you can hold the start button without hitting the brakes to put them in the accessory On mode.


anyways.
step 1. key on, one click, eng off.

then key turned to start, starter engages, spinning the engine over, can also be called cranking over the engine.(throw back to hand cranked cars I guess)

engine starts is when you can release the ignition switch from the start position, spring returns it to ON and the engine stays running.

There’s 3 positions (besides off) - it’s super simple, no need to make it so hard. Accessories on, ignition on, and starter engage ( where the spring is involved so you the starter can’t be engaged unless you hold it). The older vehicles it was more obvious because you used to have to turn the ignition counter clockwise to accessory.

 

[iamdub]

There’s 3 positions (besides off) - it’s super simple, no need to make it so hard. Accessories on, ignition on, and starter engage ( where the spring is involved so you the starter can’t be engaged unless you hold it). The older vehicles it was more obvious because you used to have to turn the ignition counter clockwise to accessory.

Lemme make sure I'm tracking here:

When you turn the key over to that first position, the accessories turn over. When you turn it over to the next position, the ignition is then turned over. If you turn it over to the third position, the starter is turned. Does the starter then turn over if it spins when electrified? If the engine can turn, then the starter can turn the engine while it's turned over. If the fuel and ignition systems are in normal turned-over condition, then the engine should, in turn, turn over. What if you you want to turn off the engine that is turned over? You turn the key back one position, right? Does this turn the engine back over? How many sides does the engine have to turn from? I'm thinking that, if it turned over to turn, then it either un-turns or is turned back over to its state where it's no longer turning, indicating it is two-sided: turned and turning (turned over) and not turned (turned back over or never turned in the first place).

What if we're discussing a lawnmower or weed trimmer? Is yanking that starter rope turning it or turning it over? Or is that cranking it, which involves turning the crankshaft in the attempt to make it turn around quickly enough to to make the engine turn over?







Could this be an apple started?

 

[Rocket Man]

Lemme make sure I'm tracking here:

When you turn the key over to that first position, the accessories turn over. When you turn it over to the next position, the ignition is then turned over. If you turn it over to the third position, the starter is turned. Does the starter then turn over if it spins when electrified? If the engine can turn, then the starter can turn the engine while it's turned over. If the fuel and ignition systems are in normal turned-over condition, then the engine should, in turn, turn over. What if you you want to turn off the engine that is turned over? You turn the key back one position, right? Does this turn the engine back over? How many sides does the engine have to turn from? I'm thinking that, if it turned over to turn, then it either un-turns or is turned back over to its state where it's no longer turning, indicating it is two-sided: turned and turning (turned over) and not turned (turned back over or never turned in the first place).

What if we're discussing a lawnmower or weed trimmer? Is yanking that starter rope turning it or turning it over? Or is that cranking it, which involves turning the crankshaft in the attempt to make it turn around quickly enough to to make the engine turn over?


View attachment 407732




Could this be an apple started?

View attachment 407735

‘xactly.