I don't know what the hell the deal is.

The combo is...

6.0 block
ARE ported heads
232/238 cam
Ported LS6 intake
28lb injectors (for now)
And it thinks its a 2004 GTO (with the engine size parameters adjusted in the program)


It's cranking great... so starter is okay.

HP Tuners links up and can communicate and scan so the PCM is okay.

I can see inputs from the sensors changing on the data logger... so sensors seem to be okay.

It's got 60 psi fuel pressure and the pump keeps running.

I can see injector constants so I assume the injectors are working.

I can see spark.

I can feel heat in the exhaust (and smell a bit of fuel, too.)

But it will not run. It just does the 1 second struggle and die trick...


I really need some ideas, guys. I've been at it for 6 hours today and got nothing

 

Vats?

 

It's disabled

Thats a good call, though! Maybe this will help another guy down the line. A list of probable causes

 

If it fires up for only a second and then shuts down, the VATS isn't turned off (even if the program says it is.)! Could be a glitch in the S/W.

 

That would really suck...

Just as a test, I burned the PCM with all three options for VATS (none, serial, pwm) and they all reacted the same. No progress

While I was at it I also verfied the voltage on the TB as well as the Cam sensor and crank sensor. They all give data that is in line with what is expected.

John, I really hope you're not right on that VATS thing... but I get a sinking feeling that you probably are.

 

I'm voting for VATS as well. When I first fired up my motor, I had the VATS box wrong and it did exactly as you describe. It would fire and run for a second or two then die. I think there is some trick to truly disabling it in the serial data cars. More than just turning it off in the program. What are you using to tune the PCM?

Could you run an F-body PCM? Those don't use the serial data VATS and are easily overridden.

You might try a search for VATS and see what comes up.

 

I've got a 2004 GTO PCM and a harness wired for it. The idea was that it would save the cost of a new HP Tuners application since I already owned that app....

I don't even know what a VATS box is

 

From my GM online tech manual...

The GTO has a vehicle theft deterrent system which is unique to this vehicle. In diagnosing this system, we have found that there are common symptoms which will shorten the time spent attempting to resolve a concern with this system. Below is what we have learned about the system to date.

VTD diagnostic:

The vehicle will momentarily start and stall even if wrong security code is received. This is a result of it taking a full second for the information from the Key FOB to travel from the ignition contacts to the PCM and back. The security light will give you a clue as to where the breakdown in communication may have occurred if the vehicle will not stay running. After having attempted to start the vehicle and the engine has started and stalled, these symptoms maybe helpful in diagnosis.

If the security light is flashing fast with the key in the on position, the concern is between the FOB and the BCM. If the security light is not on with the key in the on position, the concern is between the BCM and the PIM. If the engine starts and stalls after waiting one second or longer in the on/run position, the concern is between the PIM and the PCM.


What do you guys think?

 

In the F=bodies and C5's, the BCM sends a 5V 50Hz signal to the PCM. You can build a box "VATS box" that creates this signal and sends it to the PCM. That's what I did, and it is removable.

On the trucks, GTO and C6 the BCM and PCM are connected with a serial data line and the signal is sent through that. You cannot replicate it so you must disable VATS (VTD) in the PCM.

I would suggest at this point giving John at Speartech a call and see if he can give you some guidance. You also might want to give HPT a call and see if you are doing something wrong when disabling it. Once disabled, you should have no problems getting it to run.

 

From the HPT forum...

"VATS/BCM Relink: On vehicles that use serial VATS system, the PCM and BCM must be linked, otherwise the engine will not start. This feature allows the PCM to relink (or autolearn) to the BCM. This feature is an absolute must for mail order tuners."

 

does it die even if you give it gas?

 

Ditto

 

I spoke to John at Speartech and he says he can program it out for sure. The package is on its way this AM.

So far these guys have bailed me out a couple of times. Can't go wrong with them in my opinion!

 

I agree. John's a good guy and very helpful.

 

Things are looking up. I just got off the phone with John at Speartech. He hasn't opened it up yet but he'll get it done today.

Should go back out FEDEX overnight tonight... hopefully back in the car tomorrow by lunch time.

Speartech and FEDEX save lives We won't even start on their sanity saving merits!

 

Hopefully its fires right up this time.

 

Im thinking its a sensor perhaps.

I burnt my Crank Position Sensor wires on a cat, and my car would not fire for the life of it...

I would check all of your cam, crank, maf, etc readings to make sure they are all active.

 

All the sensors were indeed active. Allen Nelson makes a very nice wireharness that runs really snug on the engine. Not a single wire was at risk of damage. The only thing I had to do wast cut and extetend my MAF section because I'm running the MAF in the corvette position and that requires and additional 12-14 inches to get there. Had I known I needed the extra length at the time I could have asked for it and he would have made that a perfect fit, too

As for the VATS issue... Speartech resolved it and shipped my PCM out today to me. Thats about as great as service can get - I call on Monday morning, ship it out that afternoon overnight. Call on tuesday morning and its already there. Call again at the end of the workday to hear that its fixed and tested and on its way back to me via overnight. By Wednesday lunchtime I should have a running corvette again!

Good call, JohnB!

 

Speartech is the man!

 

So....? We are in edge of our seats!

Pat