Question : 3.4 Frankenbird Won't Start!

[tkoforpresident]

Ok, so many of you know of my tuning troubles but thats not really what i need help with atm. Right now the bird is in a very singular state. It will fire up on the first attempt for about 10 seconds but then stutters and dies. After that you cannot get it to start up again, try as you may. The battery is fully charged and there is fresh gas in the tank. At first i thought it was my tuning skills (or lack thereof) that was causing the non starting issues but i am beginning to think that something mechanically wrong might be going on. A quick scan with my actron scanner showed no codes being thrown by the new computer.

This is what i do know.

-there IS fuel pressure at the fuel rail upon start up so i'm assuming the fuel pump is OK

- there are no trouble codes being thrown by the pcm

On monday morning i plan to pull the plugs and see their condition as well as replace them with some new AC delco's. That might give us a good idea on whats going on inside the cylinders. Also, i'll be datalogging the initial start-up (assuming it starts on it's first attempt like it's been doing lately) that might give us a hint or two.

So what does this problem sound like from a mechanical stand point?

To me it seems almost as if it fires right up, then fuel floods the cylinders while it stalls out and dies, and then it doesn't want to start up again until a few days later.

any thoughts?

[SappySE107]

How about a datalog and no guessing. Its a huge waste of time to theorize all the possibilities.

[tkoforpresident]

Because I know a datalog won't tell me EVERYTHING. ( I'm still going to do it, thats not the point here) Besides, who's to say the car will even start up again? Or maybe I will datalog incorrectly?

If i must, I will try to reason things out by myself.

For starters i know the car is getting spark since it has been firing up on the first try.

The coil packs are new, ICM is new, plugs and wires are new (even though i'm going to replace them tomorrow- the plugs that is) and they were all working fine before all of this tuning madness. I think we can safely say it's getting spark.

God willing I will get the datalog tomorrow and post if up here.

[robertisaar]

this could be interesting to see....

any of the times that it has fired, have you given it any throttle to try and keep it alive?

[tkoforpresident]

this could be interesting to see....

any of the times that it has fired, have you given it any throttle to try and keep it alive?

Well not these past two times. But BEFORE that, remember when we were trying to do all of the VE changes? The car wouldn't always start up then so i'd have to give it gas, and shoot it up to about 2k rpms and then SLOWLY drop it down to idle, otherwise if i just let it go it would drop down and just stall out.

[SappySE107]

If you cannot datalog properly, this is going to go nowhere in a hurry.

[tkoforpresident]

lets hope for my sake that i've learned to datalog well enough.

If not....

It is... pardon my expression...

all aboard the fail boat!

[bob442]

this sounds EXACTLY like a security problem failing. and i'm going to bet thats what it is, do you have a chipped key? spare key?

http://americankeysupply.com/images/vats.jpg

Let me know ASAP pm me.

EDIT: wait wait, you said new computer, i'll almost garantee this is the problem, you'll prob gotta re-learn the vats system, i'll check up on how to do it.

[bszopi]

I was gonna say either a passkey/VATs issue, or a PROM issue. Have you made sure the PROM in in properly and seated properly?

[tkoforpresident]

that's an interesting thought. Can't i just disable VATS in the .bin?

And yes, the prom is in all the way. I am using an adapter with a .zif socket so it's kind of hard not to have it in properly.

Odd thing is that it was idling fine for a while with the new pcm and prom until just recently.

Should i try disabling vats and try again?

The key is chipped and i think i might have a spare.

max

[bob442]

try the spare, and i've had weird problems like that too with it working then dropping, its a worn key or cylinder, try the spare key first, if not i can tell/show you how to reprogram everything, or you could disable it if you have a tuner. Let me know, i'm curious as to if this is it. I dont have a problem with helping out. 12 volt is my deal.

[robertisaar]

security doesn't make sense... and when the PASSKEY module fails to keep a signal while it's already running, it kicks into fail-enable mode, which allows any key to start it, assuming it's cut correctly.

[bob442]

it only needs the signal for start up. and only reads it for a short time after crank. if you disabled the key lock you could pull the key out and drive around. none the less its worth a shot.

[tkoforpresident]

well i don't see how it could hurt anything. So i'll definitely disable VATS for the next go-around and double check the prom/adapter connection.

[robertisaar]

V4 datalog procedure(for max and anyone else that needs a reminder)

open TPV4
wait 10 secs or register
click the splash screen
assuming you have the ports set up correctly and the ALDL cable connected:
press F4 to bring up the ALDL screen
click select log file for recording, make a log file on the desktop(for simplicity)
ensure you have the correct ADS loaded for the mask you are using
roll the key forward so that the dash lights up.
if the ADS has a mode 8 command, be sure to select it and press send command a few times. i usually hit it ~5 times for good measure(FWIW:V5 does this automatically)
now, click connect to ECM.
when it connects, press the record button near the bottom right side of the dialog box. check to see the sample rate in the top right corner. it should be ~8-11 Hz. watch the packet error count as well. it will probably go up slowly no matter what for certain masks, but for the most part it should remain at/near 0.
click close.
crank the car, should fire up.
look back at the laptop to make sure nothing strange has happened to the laptop during cranking and that it is still recording.
drive/idle/whatever to your heart's content.
when finished, either go to the top of the screen, or press F4 and press the stop button to finish recording.
TP should ask for a session name(IIRC), then to export the log, open the F4 menu, select the applicable log, then click Export to CSV, name the file and save to desktop(simplicity again).
upload if desired.